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Sample records for alaska volcano observatory

  1. Alaska Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Murray, Tom; Read, Cyrus

    2008-01-01

    Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

  2. Alaska Volcano Observatory Monitoring Station

    An Alaska Volcano Observatory Monitoring station with Peulik Volcano behind. This is the main repeater for the Peulik monitoring network located on Whale Mountain, Beecharaof National Wildlife Refuge....

  3. Alaska Volcano Observatory at 20

    NASA Astrophysics Data System (ADS)

    Eichelberger, J. C.

    2008-12-01

    The Alaska Volcano Observatory (AVO) was established in 1988 in the wake of the 1986 Augustine eruption through a congressional earmark. Even within the volcanological community, there was skepticism about AVO. Populations directly at risk in Alaska were small compared to Cascadia, and the logistical costs of installing and maintaining monitoring equipment were much higher. Questions were raised concerning the technical feasibility of keeping seismic stations operating through the long, dark, stormy Alaska winters. Some argued that AVO should simply cover Augustine with instruments and wait for the next eruption there, expected in the mid 90s (but delayed until 2006), rather than stretching to instrument as many volcanoes as possible. No sooner was AVO in place than Redoubt erupted and a fully loaded passenger 747 strayed into the eruption cloud between Anchorage and Fairbanks, causing a powerless glide to within a minute of impact before the pilot could restart two engines and limp into Anchorage. This event forcefully made the case that volcano hazard mitigation is not just about people and infrastructure on the ground, and is particularly important in the heavily traveled North Pacific where options for flight diversion are few. In 1996, new funding became available through an FAA earmark to aggressively extend volcano monitoring far into the Aleutian Islands with both ground-based networks and round-the-clock satellite monitoring. Beyond the Aleutians, AVO developed a monitoring partnership with Russians volcanologists at the Institute of Volcanology and Seismology in Petropavlovsk-Kamchatsky. The need to work together internationally on subduction phenomena that span borders led to formation of the Japan-Kamchatka-Alaska Subduction Processes (JKASP) consortium. JKASP meets approximately biennially in Sapporo, Petropavlovsk, and Fairbanks. In turn, these meetings and support from NSF and the Russian Academy of Sciences led to new international education and research opportunities for Russian and American students. AVO was a three-way partnership of the federal and state geological surveys and the state university from the start. This was not a flowering of ecumenism but was rather at the insistence of the Alaska congressional delegation. Such shared enterprises are not managerially convenient, but they do bring a diversity of roles, thinking, and expertise that would not otherwise be possible. Through AVO, the USGS performs its federally mandated role in natural hazard mitigation and draws on expertise available from its network of volcano observatories. The Alaska Division of Geological and Geophysical Surveys performs a similar role at the state level and, in the tradition of state surveys, provides important public communications, state data base, and mapping functions. The University of Alaska Fairbanks brought seismological, remote sensing, geodetic, petrological, and physical volcanological expertise, and uniquely within US academia was able to engage students directly in volcano observatory activities. Although this "model" cannot be adopted in total elsewhere, it has served to point the USGS Volcano Hazards Program in a direction of greater openness and inclusiveness.

  4. 2011 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Maharrey, J. Zebulon; Neal, Christina A.

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near three separate volcanic centers in Alaska during 2011. The year was highlighted by the unrest and eruption of Cleveland Volcano in the central Aleutian Islands. AVO annual summaries no longer report on activity at Russian volcanoes.

  5. Twenty years of Alaska Volcano Observatory's contributions to seismology

    NASA Astrophysics Data System (ADS)

    Dixon, J. P.; McNutt, S. R.; Power, J. A.; West, M.

    2008-12-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute at the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys observed its 20th anniversary in 2008. The AVO seismic network, inherited from AVO partners in 1988, consisted of three small-aperture subnetworks on Mount Spurr, Redoubt Volcano and Augustine Volcano and regional stations for a total of 23 short-period instruments (two with three-components). Twenty years later, the AVO network has expanded to 192 stations (23 three-component short-period, and 15 broadband) on 33 volcanoes spanning 2500 km across the Aleutian arc in one of the most remote and challenging environments in the world. The AVO seismic network provides for a unique data set. Within the seismically active Aleutian Arc, there are instrumented volcanoes which exhibit a variety of chemical compositions and eruptive styles. With each individual volcanic center similarly instrumented and all data analyzed in a consistent manner AVO has produced a data set suitable for making seismic comparisons across a wide suite of volcanoes. In twenty years, the AVO has captured data sets for eruptions at Augustine, Kasatochi, Okmok, Pavlof, Redoubt, Shishaldin, Spurr, and Venianinof. AVO data set also includes several volcanic-tectonic swarms, most notably at Akutan, Iliamna, Mageik, Martin, Shishaldin, and Tanaga. This broad approach to volcano seismology has led to a better understanding of precursory earthquake swarms, variations in background rates, triggered seismicity, the structure of volcanoes, volcanic tremor and deep long period earthquakes, among numerous other topics. The AVO also incorporates data from seismic stations operated by both the Alaska Earthquake Information Center and West Coast and Alaska Tsunami Warning Center to help locate some of the 70,000 earthquakes in the AVO catalog. In exchange AVO provides dense seismic data from the Aleutians which are routinely used to locate earthquakes throughout the north Pacific. In addition to seismic data, AVO also collects data from campaign and continuous GPS, web cameras, and pressure sensors.

  6. 1994 Volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Doukas, Michael P.; McGimsey, Robert G.

    1995-01-01

    During 1994, the Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, or false alarms at nine volcanic centers-- Mount Sanford, Iliamna, the Katmai group, Kupreanof, Mount Veniaminof, Shishaldin, Makushin, Mount Cleveland and Kanaga (table 1). Of these volcanoes, AVO has a real time, continuously recording seismic network only at Iliamna, which is located in the Cook Inlet area of south-central Alaska (fig. 1). AVO has dial-up access to seismic data from a 5-station network in the general region of the Katmai group of volcanoes. The remaining unmonitored volcanoes are located in sparsely populated areas of the Wrangell Mountains, the Alaska Peninsula, and the Aleutian Islands (fig. 1). For these volcanoes, the AVO monitoring program relies chiefly on receipt of pilot reports, observations of local residents and analysis of satellite imagery.

  7. 2013 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Dixon, James P.; Cameron, Cheryl; McGimsey, Robert G.; Neal, Christina A.; Waythomas, Chris

    2015-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, volcanic unrest or suspected unrest, and seismic events at 18 volcanic centers in Alaska during 2013. Beginning with the 2013 AVO Summary of Events, the annual description of the AVO seismograph network and activity, once a stand-alone publication, is now part of this report. Because of this change, the annual summary now contains an expanded description of seismic activity at Alaskan volcanoes. Eruptions occurred at three volcanic centers in 2013: Pavlof Volcano in May and June, Mount Veniaminof Volcano in June through December, and Cleveland Volcano throughout the year. None of these three eruptive events resulted in 24-hour staffing at AVO facilities in Anchorage or Fairbanks.

  8. 2012 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Herrick, Julie A.; Neal, Christina A.; Cameron, Cheryl E.; Dixon, James P.; McGimsey, Robert G.

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, or suspected unrest at 11 volcanic centers in Alaska during 2012. Of the two verified eruptions, one (Cleveland) was clearly magmatic and the other (Kanaga) was most likely a single phreatic explosion. Two other volcanoes had notable seismic swarms that probably were caused by magmatic intrusions (Iliamna and Little Sitkin). For each period of clear volcanic unrest, AVO staff increased monitoring vigilance as needed, reviewed eruptive histories of the volcanoes in question to help evaluate likely outcomes, and shared observations and interpretations with the public. 2012 also was the 100th anniversary of Alaska’s Katmai-Novarupta eruption of 1912, the largest eruption on Earth in the 20th century and one of the most important volcanic eruptions in modern times. AVO marked this occasion with several public events.

  9. Development of Alaska Volcano Observatory Seismic Networks, 1988-2008

    NASA Astrophysics Data System (ADS)

    Tytgat, G.; Paskievitch, J. F.; McNutt, S. R.; Power, J. A.

    2008-12-01

    The number and quality of seismic stations and networks on Alaskan volcanoes have increased dramatically in the 20 years from 1988 to 2008. Starting with 28 stations on six volcanoes in 1988, the Alaska Volcano Observatory (AVO) now operates 194 stations in networks on 33 volcanoes spanning the 2000 km Aleutian Arc. All data are telemetered in real time to laboratory facilities in Fairbanks and Anchorage and recorded on digital acquisition systems. Data are used for both monitoring and research. The basic and standard network designs are driven by practical considerations including geography and terrain, access to commercial telecommunications services, and environmental vulnerability. Typical networks consist of 6 to 8 analog stations, whose data can be telemetered to fit on a single analog telephone circuit terminated ultimately in either Fairbanks or Anchorage. Towns provide access to commercial telecommunications and signals are often consolidated for telemetry by remote computer systems. Most AVO stations consist of custom made fiberglass huts that house the batteries, electronics, and antennae. Solar panels are bolted to the south facing side of the huts and the seismometers are buried nearby. The huts are rugged and have allowed for good station survivability and performance reliability. However, damage has occurred from wind, wind-blown pumice, volcanic ejecta, lightning, icing, and bears. Power is provided by multiple isolated banks of storage batteries charged by solar panels. Primary cells are used to provide backup power should the rechargable system fail or fall short of meeting the requirement. In the worst cases, snow loading blocks the solar panels for 7 months, so sufficient power storage must provide power for at least this long. Although primarily seismic stations, the huts and overall design allow additional instruments to be added, such as infrasound sensors, webcams, electric field meters, etc. Yearly maintenance visits are desirable, but some stations have operated for more than 10 years with no site visits. In the last five years AVO began upgrading select analog networks by adding telemetered broadband digital seismometers and GPS instruments.

  10. 2010 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Herrick, Julie; Girina, O.A.; Chibisova, Marina; Rybin, Alexander; McGimsey, Robert G.; Dixon, Jim

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest or suspected unrest at 12 volcanic centers in Alaska during 2010. The most notable volcanic activity consisted of intermittent ash emissions from long-active Cleveland volcano in the Aleutian Islands. AVO staff also participated in hazard communication regarding eruptions or unrest at seven volcanoes in Russia as part of an ongoing collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  11. 2009 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Girina, Olga A.; Chibisova, Marina; Rybin, Alexander

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, and reports of unusual activity at or near eight separate volcanic centers in Alaska during 2009. The year was highlighted by the eruption of Redoubt Volcano, one of three active volcanoes on the western side of Cook Inlet and near south-central Alaska's population and commerce centers, which comprise about 62 percent of the State's population of 710,213 (2010 census). AVO staff also participated in hazard communication and monitoring of multiple eruptions at ten volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  12. 1996 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.

    1997-01-01

    During 1996, the Alaska Volcano Observatory (AVO) responded to eruptive activity, anomalous seismicity, or suspected volcanic activity at 10 of the approximately 40 active volcanic centers in the state of Alaska. As part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also disseminated information about eruptions and other volcanic unrest at six volcanic centers on the Kamchatka Peninsula and in the Kurile Islands, Russia.

  13. 2008 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Cameron, Cheryl E.; Nuzhdaev, Anton A.; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest or suspected unrest at seven separate volcanic centers in Alaska during 2008. Significant explosive eruptions at Okmok and Kasatochi Volcanoes in July and August dominated Observatory operations in the summer and autumn. AVO maintained 24-hour staffing at the Anchorage facility from July 12 through August 28. Minor eruptive activity continued at Veniaminof and Cleveland Volcanoes. Observed volcanic unrest at Cook Inlet's Redoubt Volcano presaged a significant eruption in the spring of 2009. AVO staff also participated in hazard communication regarding eruptions or unrest at nine volcanoes in Russia as part of a collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  14. 2007 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Dixon, James P.; Malik, Nataliya; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2007. The year was highlighted by the eruption of Pavlof, one of Alaska's most frequently active volcanoes. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the autumn of 2006 and continued to emit copious amounts of steam and volcanic gas into 2007. Redoubt Volcano showed the first signs of the unrest that would unfold in 2008-09. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  15. 2006 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Manevich, Alexander; Rybin, Alexander

    2008-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2006. A significant explosive eruption at Augustine Volcano in Cook Inlet marked the first eruption within several hundred kilometers of principal population centers in Alaska since 1992. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the fall of 2006 and continued to emit copious amounts of volcanic gas into 2007. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  16. Hazard communication by the Alaska Volcano Observatory Concerning the 2008 Eruptions of Okmok and Kasatochi Volcanoes, Aleutian Islands, Alaska

    NASA Astrophysics Data System (ADS)

    Adleman, J. N.; Cameron, C. E.; Neal, T. A.; Shipman, J. S.

    2008-12-01

    The significant explosive eruptions of Okmok and Kasatochi volcanoes in 2008 tested the hazard communication systems at the Alaska Volcano Observatory (AVO) including a rigorous test of the new format for written notices of volcanic activity. AVO's Anchorage-based Operations facility (Ops) at the USGS Alaska Science Center serves as the hub of AVO's eruption response. From July 12 through August 28, 2008 Ops was staffed around the clock (24/7). Among other duties, Ops staff engaged in communicating with the public, media, and other responding federal and state agencies and issued Volcanic Activity Notices (VAN) and Volcano Observatory Notifications for Aviation (VONA), recently established and standardized products to announce eruptions, significant activity, and alert level and color code changes. In addition to routine phone communications with local, national and international media, on July 22, AVO held a local press conference in Ops to share observations and distribute video footage collected by AVO staff on board a U.S. Coast Guard flight over Okmok. On July 27, AVO staff gave a public presentation on the Okmok eruption in Unalaska, AK, 65 miles northeast of Okmok volcano and also spoke with local public safety and industry officials, observers and volunteer ash collectors. AVO's activity statements, photographs, and selected data streams were posted in near real time on the AVO public website. Over the six-week 24/7 period, AVO staff logged and answered approximately 300 phone calls in Ops and approximately 120 emails to the webmaster. Roughly half the logged calls were received from interagency cooperators including NOAA National Weather Service's Alaska Aviation Weather Unit and the Center Weather Service Unit, both in Anchorage. A significant number of the public contacts were from mariners reporting near real-time observations and photos of both eruptions, as well as the eruption of nearby Cleveland Volcano on July 21. As during the 2006 eruption of Augustine volcano in Cook Inlet, Alaska, the number of calls to Ops, emails to the webmaster, and the amount of data served via the AVO website greatly increased during elevated volcanic activity designated by the USGS aviation color code and volcano alert level. Lessons learned include, Ops staffing requirements during periods of high call volume, the need for ash fall hazard information in multiple languages, and the value of real-time observations of remote Aleutian eruptions made by local mariners. An important theme of public inquiries concerned the amount and potential climate impacts of the significant sulfur dioxide gas and ash plumes emitted by Okmok and Kasatochi, including specific questions on the amount of sulfur dioxide discharged during each eruption. The significant plumes produced at the onset of the Okmok and Kasatochi eruptions also had lengthy national and international aviation impacts and yet-to-be resolved hemispherical or possible global, climactic effects.

  17. Response of the Alaska Volcano Observatory to Public Inquiry Concerning the 2006 Eruption of Augustine Volcano, Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Adleman, J. N.

    2006-12-01

    The 2006 eruption of Augustine Volcano provided the Alaska Volcano Observatory (AVO) with an opportunity to test its newly renovated Operations Center (Ops) at the Alaska Science Center in Anchorage. Because of the demand for interagency operations and public communication, Ops became the hub of Augustine monitoring activity, twenty-four hours a day, seven days a week, from January 10 through May 19, 2006. During this time, Ops was staffed by 17 USGS AVO staff, and over two dozen Fairbanks-based AVO staff from the Alaska Department of Geological and Geophysical Surveys and the University of Alaska Fairbanks Geophysical Institute and USGS Volcano Hazards Program staff from outside Alaska. This group engaged in communicating with the public, media, and other responding agencies throughout the eruption. Before and during the eruption, reference sheets - ;including daily talking - were created, vetted, and distributed to prepare staff for questions about the volcano. These resources were compiled into a binder stationed at each Ops phone and available through the AVO computer network. In this way, AVO was able to provide a comprehensive, uniform, and timely response to callers and emails at all three of its cooperative organizations statewide. AVO was proactive in scheduling an Information Scientist for interviews on-site with Anchorage television stations and newspapers several times a week. Scientists available, willing, and able to speak clearly about the current activity were crucial to AVO's response. On January 19, 2006, two public meetings were held in Homer, 120 kilometers northeast of Augustine Volcano. AVO, the West Coast Alaska Tsunami Warning Center, and the Kenai Peninsula Borough Office of Emergency Management gave brief presentations explaining their roles in eruption response. Representatives from several local, state, and federal agencies were also available. In addition to communicating with the public by daily media interviews and phone calls to Ops, all activity reports, images, and selected data streams were posted in near real time on the AVO public website. Hundreds of emails were answered. The AVO website quickly became highly organized and the most up-to-date and comprehensive place for anyone with internet access to learn about the eruption and AVO's response. This was the first such organized response of AVO and may be the outgrowth of increased expectations of AVO by the public. From November 28, 2005, through May 16, 2006, staff logged and answered approximately 400 phone calls and 1000 emails about Augustine. AVO's interagency response plan and relationships with other key agencies helped in responding to requests from the media and the public for a wide variety of information. However, the most frequent questions from callers were about ash fall advisories and what to do in the event of an ash fall. This highlighted the need to produce coordinated, co-agency reporting of ash fall potential and recommended preparation.

  18. 1995 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.

    1996-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity (SVA) at 6 volcanic centers in 1995: Mount Martin (Katmai Group), Mount Veniaminof, Shishaldin, Makushin, Kliuchef/Korovin, and Kanaga. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) on the 1995 eruptions of 2 Russian volcanoes: Bezymianny and Karymsky. This report summarizes volcanic activity in Alaska during 1995 and the AVO response, as well as information on the 2 Kamchatkan eruptions. Only those reports or inquiries that resulted in a "significant" investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of phone calls throughout the year reporting steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1995 response record.

  19. 1997 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Wallace, Kristi L.

    1999-01-01

    The Alaska Volcano Observatory (AVO) monitors over 40 historically active volcanoes along the Aleutian Arc. Twenty are seismically monitored and for the rest, the AVO monitoring program relies mainly on pilot reports, observations of local residents and ship crews, and daily analysis of satellite images. In 1997, AVO responded to eruptive activity or suspect volcanic activity at 11 volcanic centers: Wrangell, Sanford, Shrub mud volcano, Iliamna, the Katmai group (Martin, Mageik, Snowy, and Kukak volcanoes), Chiginagak, Pavlof, Shishaldin, Okmok, Cleveland, and Amukta. Of these, AVO has real-time, continuously recording seismic networks at Iliamna, the Katmai group, and Pavlof. The phrase “suspect volcanic activity” (SVA), used to characterize several responses, is an eruption report or report of unusual activity that is subsequently determined to be normal or enhanced fumarolic activity, weather-related phenomena, or a non-volcanic event. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) about the 1997 activity of 5 Russian volcanoes--Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Alaid (SVA). This report summarizes volcanic activity and SVA in Alaska during 1997 and the AVO response, as well as information on the reported activity at the Russian volcanoes. Only those reports or inquiries that resulted in a “significant” investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of reports throughout the year of steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1997 response record.

  20. 2005 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, R.G.; Neal, C.A.; Dixon, J.P.; Ushakov, Sergey

    2008-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity at or near 16 volcanoes in Alaska during 2005, including the high profile precursory activity associated with the 2005?06 eruption of Augustine Volcano. AVO continues to participate in distributing information about eruptive activity on the Kamchatka Peninsula, Russia, and in the Kurile Islands of the Russian Far East, in conjunction with the Kamchatkan Volcanic Eruption Response Team (KVERT) and the Sakhalin Volcanic Eruption Response Team (SVERT), respectively. In 2005, AVO helped broadcast alerts about activity at 8 Russian volcanoes. The most serious hazard posed from volcanic eruptions in Alaska, Kamchatka, or the Kurile Islands is the placement of ash into the atmosphere at altitudes traversed by jet aircraft along the North Pacific and Russian Trans East air routes. AVO, KVERT, and SVERT work collaboratively with the National Weather Service, Federal Aviation Administration, and the Volcanic Ash Advisory Centers to provide timely warnings of volcanic eruptions and the production and movement of ash clouds.

  1. The Alaska Volcano Observatory Website a Tool for Information Management and Dissemination

    NASA Astrophysics Data System (ADS)

    Snedigar, S. F.; Cameron, C. E.; Nye, C. J.

    2006-12-01

    The Alaska Volcano Observatory's (AVO's) website served as a primary information management tool during the 2006 eruption of Augustine Volcano. The AVO website is dynamically generated from a database back- end. This system enabled AVO to quickly and easily update the website, and provide content based on user- queries to the database. During the Augustine eruption, the new AVO website was heavily used by members of the public (up to 19 million hits per day), and this was largely because the AVO public pages were an excellent source of up-to-date information. There are two different, yet fully integrated parts of the website. An external, public site (www.avo.alaska.edu) allows the general public to track eruptive activity by viewing the latest photographs, webcam images, webicorder graphs, and official information releases about activity at the volcano, as well as maps, previous eruption information, bibliographies, and rich information about other Alaska volcanoes. The internal half of the website hosts diverse geophysical and geological data (as browse images) in a format equally accessible by AVO staff in different locations. In addition, an observation log allows users to enter information about anything from satellite passes to seismic activity to ash fall reports into a searchable database. The individual(s) on duty at the watch office use forms on the internal website to post a summary of the latest activity directly to the public website, ensuring that the public website is always up to date. The internal website also serves as a starting point for monitoring Alaska's volcanoes. AVO's extensive image database allows AVO personnel to upload many photos, diagrams, and videos which are then available to be browsed by anyone in the AVO community. Selected images are viewable from the public page. The primary webserver is housed at the University of Alaska Fairbanks, and holds a MySQL database with over 200 tables and several thousand lines of php code gluing the database and website together. The database currently holds 95 GB of data. Webcam images and webicorder graphs are pulled from servers in Anchorage every few minutes. Other servers in Fairbanks generate earthquake location plots and spectrograms.

  2. Implementation of Simple and Functional Web Applications at the Alaska Volcano Observatory Remote Sensing Group

    NASA Astrophysics Data System (ADS)

    Skoog, R. A.

    2007-12-01

    Web pages are ubiquitous and accessible, but when compared to stand-alone applications they are limited in capability. The Alaska Volcano Observatory (AVO) Remote Sensing Group has implemented web pages and supporting server software that provide relatively advanced features to any user able to meet basic requirements. Anyone in the world with access to a modern web browser (such as Mozilla Firefox 1.5 or Internet Explorer 6) and reasonable internet connection can fully use the tools, with no software installation or configuration. This allows faculty, staff and students at AVO to perform many aspects of volcano monitoring from home or the road as easily as from the office. Additionally, AVO collaborators such as the National Weather Service and the Anchorage Volcanic Ash Advisory Center are able to use these web tools to quickly assess volcanic events. Capabilities of this web software include (1) ability to obtain accurate measured remote sensing data values on an semi- quantitative compressed image of a large area, (2) to view any data from a wide time range of data swaths, (3) to view many different satellite remote sensing spectral bands and combinations, to adjust color range thresholds, (4) and to export to KML files which are viewable virtual globes such as Google Earth. The technologies behind this implementation are primarily Javascript, PHP, and MySQL which are free to use and well documented, in addition to Terascan, a commercial software package used to extract data from level-0 data files. These technologies will be presented in conjunction with the techniques used to combine them into the final product used by AVO and its collaborators for operational volcanic monitoring.

  3. Use of new and old technologies and methods by the Alaska Volcano Observatory during the 2006 eruption of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Murray, T. L.; Nye, C. J.; Eichelberger, J. C.

    2006-12-01

    The recent eruption of Augustine Volcano was the first significant volcanic event in Cook Inlet, Alaska since 1992. In contrast to eruptions at remote Alaskan volcanoes that mainly affect aviation, ash from previous eruptions of Augustine has affected communities surrounding Cook Inlet, home to over half of Alaska's population. The 2006 eruption validated much of AVO's advance preparation, underscored the need to quickly react when a problem or opportunity developed, and once again demonstrated that while technology provides us with wonderful tools, professional relationships, especially during times of crisis, are still important. Long-term multi-parametric instrumental monitoring and background geological and geophysical studies represent the most fundamental aspect of preparing for any eruption. Once significant unrest was detected, AVO augmented the existing real-time network with additional instrumentation including web cameras. GPS and broadband seismometers that recorded data on site were also quickly installed as their data would be crucial for post-eruption research. Prior to 2006, most of most of AVO's eruption response plans and protocols had focused on the threat to aviation rather than ground-based hazards. However, the relationships and protocols developed for the aviation threat were sufficient to be adapted to the ash fall hazard, though it is apparent that more work, both scientific and with response procedures, is needed. Similarly, protocols were quickly developed for warning of a flank- collapse induced tsunami. Information flow within the observatory was greatly facilitated by an internal web site that had been developed and refined specifically for eruption response. Because AVO is a partnership of 3 agencies (U.S. Geological Survey, University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys) with offices in both Fairbanks and Anchorage, web and internet-facing data servers provided reliable and rapid access to much of the information to each office. Information flow between the observatory and the public and emergency responders was accomplished through the AVO public web site, e-mail, faxes, public meetings, and frequent phone calls. AVO's newly renovated Operations Center in Anchorage provided a central 24/7 site to both receive and disseminate information and conduct media interviews. With selected real time data sets and hourly updates provided on the AVO public web site, many emergency responders and even private citizens tracked the eruption in near real time themselves.

  4. USGS Hawaiian Volcano Observatory

    The USGS Hawaiian Volcano Observatory is perched on the rim of Kilauea Volcano's summit caldera (next to the Thomas A. Jaggar Museum in Hawai'i Volcanoes National Park), providing a spectacular view of the active vent in Halema‘uma‘u Crater....

  5. Cascades Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Driedger, Carolyn; Pallister, John

    2008-01-01

    Washington's Mount St. Helens volcano reawakens explosively on October 1, 2004, after 18 years of quiescence. Scientists at the U.S. Geological Survey's Cascades Volcano Observatory (CVO) study and observe Mount St. Helens and other volcanoes of the Cascade Range in Washington, Oregon, and northern California that hold potential for future eruptions. CVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Mount St. Helens and CVO at http://vulcan.wr.usgs.gov/.

  6. Renewed Unrest at Mount Spurr Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Power, John

    2004-10-01

    The Alaska Volcano Observatory (AVO), a Cooperative Program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys, has detected unrest at Mount Spurr volcano, located about 125 km west of Anchorage, Alaska, at the northeast end of the Aleutian volcanic arc. This activity consists of increased seismicity, melting of the summit ice cap, and substantial rates of CO2 and H2S emission. The current unrest is centered beneath the volcano's 3374-m-high summit, whose last known eruption was 5000-6000 years ago. Since then, Crater Peak, 2309 m in elevation and 4 km to the south, has been the active vent. Recent eruptions occurred in 1953 and 1992.

  7. Monitoring and analyses of volcanic activity using remote sensing data at the Alaska Volcano Observatory: Case study for Kamchatka, Russia, December 1997

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Dean, K., G.; Dehn, J.; Miller, T., P.; Kirianov, V. Yu.

    There are about 100 potentially active volcanoes in the North Pacific Ocean region that includes Alaska, the Kamchatka Peninsula, and the Kurile Islands, but fewer than 25% are monitored seismically. The region averages about five volcanic eruptions per year, and more than 20,000 passengers and millions of dollars of cargo fly the air routes in this region each day. One of the primary public safety objectives of the Alaska Volcano Observatory (AVO) is to mitigate the hazard posed by volcanic ash clouds drifting into these busy air traffic routes. The AVO uses real-time remote sensing data (AVHRR, GOES, and GMS) in conjunction with other methods (primarily seismic) to monitor and analyze volcanic activity in the region. Remote sensing data can be used to detect volcanic thermal anomalies and to provide unique information on the location, movement, and composition of volcanic eruption clouds. Satellite images are routinely analyzed twice each day at AVO and many times per day during crisis situations. As part of its formal working relationship with the Kamchatka Volcanic Eruption Response Team (KVERT), the AVO provides satellite observations of volcanic activity in Kamchatka and distributes notices of volcanic eruptions from KVERT to non-Russian users in the international aviation community. This paper outlines the current remote sensing capabilities and operations of the AVO and describes the responsibilities and procedures of federal agencies and international aviation organizations for volcanic eruptions in the North Pacific region. A case study of the December 4, 1997, eruption of Bezymianny volcano, Russia, is used to illustrate how real-time remote sensing and hazard communication are used to mitigate the threat of volcanic ash to aircraft.

  8. Eruption of Alaska volcano breaks historic pattern

    USGS Publications Warehouse

    Larsen, Jessica; Neal, Christina A.; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick L.

    2009-01-01

    In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (~2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud "thunder," lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

  9. Alaska volcanoes guidebook for teachers

    USGS Publications Warehouse

    Adleman, Jennifer N.

    2011-01-01

    Alaska’s volcanoes, like its abundant glaciers, charismatic wildlife, and wild expanses inspire and ignite scientific curiosity and generate an ever-growing source of questions for students in Alaska and throughout the world. Alaska is home to more than 140 volcanoes, which have been active over the last 2 million years. About 90 of these volcanoes have been active within the last 10,000 years and more than 50 of these have been active since about 1700. The volcanoes in Alaska make up well over three-quarters of volcanoes in the United States that have erupted in the last 200 years. In fact, Alaska’s volcanoes erupt so frequently that it is almost guaranteed that an Alaskan will experience a volcanic eruption in his or her lifetime, and it is likely they will experience more than one. It is hard to imagine a better place for students to explore active volcanism and to understand volcanic hazards, phenomena, and global impacts. Previously developed teachers’ guidebooks with an emphasis on the volcanoes in Hawaii Volcanoes National Park (Mattox, 1994) and Mount Rainier National Park in the Cascade Range (Driedger and others, 2005) provide place-based resources and activities for use in other volcanic regions in the United States. Along the lines of this tradition, this guidebook serves to provide locally relevant and useful resources and activities for the exploration of numerous and truly unique volcanic landscapes in Alaska. This guidebook provides supplemental teaching materials to be used by Alaskan students who will be inspired to become educated and prepared for inevitable future volcanic activity in Alaska. The lessons and activities in this guidebook are meant to supplement and enhance existing science content already being taught in grade levels 6–12. Correlations with Alaska State Science Standards and Grade Level Expectations adopted by the Alaska State Department of Education and Early Development (2006) for grades six through eleven are listed at the beginning of each activity. A complete explanation, including the format of the Alaska State Science Standards and Grade Level Expectations, is available at the beginning of each grade link at http://www.eed.state.ak.us/tls/assessment/GLEHome.html.

  10. The USGS Hawaiian Volcano Observatory Monitors Kilauea's Summit Eruption

    The USGS Hawaiian Volcano Observatory (foreground) is located on the caldera rim of Kilauea Volcano, Hawai'i?the most active volcano in the world. The observatory's location provides an excellent view of summit eruptive activity, which began in 2008....

  11. Use of SAR data to study active volcanoes in Alaska

    USGS Publications Warehouse

    Dean, K.G.; Engle, K.; Lu, Zhiming; Eichelberger, J.; Near, T.; Doukas, M.

    1996-01-01

    Synthetic Aperture Radar (SAR) data of the Westdahl, Veniaminof, and Novarupta volcanoes in the Aleutian Arc of Alaska were analysed to investigate recent surface volcanic processes. These studies support ongoing monitoring and research by the Alaska Volcano Observatory (AVO) in the North Pacific Ocean Region. Landforms and possible crustal deformation before, during, or after eruptions were detected and analysed using data from the European Remote Sensing Satellites (ERS), the Japanese Earth Resources Satellite (JERS) and the US Seasat platforms. Field observations collected by scientists from the AVO were used to verify the results from the analysis of SAR data.

  12. Use of SAR data to study active volcanoes in Alaska

    USGS Publications Warehouse

    Dean, K.G.; Engle, K.; Lu, Zhiming; Eichelberger, J.; Neal, T.; Doukas, M.

    1996-01-01

    Synthetic Aperture Radar (SAR) data of Westdahl, Veniaminof, and Novarupta volcanoes in the Aleutian Arc of Alaska were analyzed to investigate recent surface volcanic processes. These studies support ongoing monitoring and research by the Alaska Volcano Observatory (AVO) in the North Pacific Ocean Region. Landforms and possible crustal deformation before, during, or after eruptions were detected and analyzed using data from the European Remote Sensing Satellites (ERS), Japanese Earth Resources Satellite (JERS) and the U. S. Seasat platforms. Field observations collected by scientists from the AVO were used to verify the results from the analysis of SAR data.

  13. The eruption of Redoubt Volcano, Alaska, December 14,1989-August 31, 1990

    SciTech Connect

    Brantley, S.R.

    1990-12-01

    This paper reports on explosive volcanic activity at Redoubt Volcano, 177 km southwest of Anchorage, Alaska, which generated numerous tephra plumes that disrupted air traffic above southern Alaska, damaged aircraft, and caused locally heavy tephra fall. Pyroclastic flows triggered debris flows that inundated part of an oil-tanker facility, temporarily suspending oil production in Cook Inlet. The newly established Alaska Volcano Observatory increased its monitoring effort and disseminated volcanic hazard information to government agencies, industry, and the public.

  14. The origin of the Hawaiian Volcano Observatory

    SciTech Connect

    Dvorak, John

    2011-05-15

    I first stepped through the doorway of the Hawaiian Volcano Observatory in 1976, and I was impressed by what I saw: A dozen people working out of a stone-and-metal building perched at the edge of a high cliff with a spectacular view of a vast volcanic plain. Their primary purpose was to monitor the island's two active volcanoes, Kilauea and Mauna Loa. I joined them, working for six weeks as a volunteer and then, years later, as a staff scientist. That gave me several chances to ask how the observatory had started.

  15. Don Swanson at Ash Outcrop Near Volcano Observatory

    Don Swanson (USGS Hawaiian Volcano Observatory) shows scientists in the CSAV International class how layers of ash outside of HVO indicate past explosive eruptions of Kilauea. Hawaiian Volcano Observatory, Hawaii Island, Hawaii...

  16. 2. PARKING LOT AT JAGGAR MUSEUM, VOLCANO OBSERVATORY. VIEW OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. PARKING LOT AT JAGGAR MUSEUM, VOLCANO OBSERVATORY. VIEW OF MEDIAN. NOTE VOLCANIC STONE CURBING (EDGING) TYPICAL OF MOST PARKING AREAS; TRIANGLING AT END NOT TYPICAL. MAUNA LOA VOLCANO IN BACK. - Crater Rim Drive, Volcano, Hawaii County, HI

  17. Thomas A. Jaggar, Hawaiian Volcano Observatory

    Thomas A. Jaggar founded the Hawaiian Volcano Observatory in 1912 and served as its Director until 1940.  Shown here in 1925, Jaggar is at work in HVO's first building, which, at the time, was located on the northeast rim of Kīlauea Volcano’s summit caldera, near the present-day Volc...

  18. 4D seismic structure beneath Spurr volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Jakovlev, Andrey; Koulakov, Ivan; West, Michael

    2013-04-01

    Mount Spurr is a large volcano located 125 km west of Anchorage, Alaska. This dominantly andesitic stratovolcano with summit elevation of 3374 m is the highest volcano of the Aleutian Arc. Two historical eruptions of Spurr volcano have occurred in 1953 and 1992. Moreover, from July 2004 to February 2006 continuous non-eruptive activity was observed. Since 1988 the Alaska Volcano Observatory (AVO) collects information about Alaska seismicity. In this work we present evolution of the seismic structure beneath Spurr volcano obtained from 4D seismic tomography. In total 222605 rays (129387 P and 93218 S rays) coming from 17068 earthquakes and registered by 26 station of AVO seismic network were used for the tomographic inversion. After analysis of the seismic and volcano activity, 5 time periods were chosen. Variations of P and S wave velocity anomalies and Vp/Vs ratio in this 5 time periods were obtained after simultaneous iterative inversion of one combined matrix. Smoothness of the velocity anomalies variation in space and time are controlled by two additional matrix block. Results reveal clear correlation of the seismic structure and volcanic activity. In the first (October 1989 - July 1996) and fourth (January 2004 - January 2007) time periods, characterized by high activity, a prominent vertical channel directly beneath volcano is observed on the vertical sections. This channel is characterized by very high values of Vp/Vs ratio (increased P wave and decreased S wave velocities). During the three other periods with no volcanic activity, when the relaxation of the media took place, seismic structure becomes more homogeneous without strong velocity anomalies. Special attention is paid to estimation of the model resolution in different time periods and analysis of possible artifacts due to different ray coverage in different periods. Therefore a lot synthetic and real data tests were performed.

  19. The Earthscope Plate Boundary Observatory Akutan Alaskan Volcano Network Installation

    NASA Astrophysics Data System (ADS)

    Pauk, B.; Jackson, M.; Mencin, D.; Power, J.; Gallaher, W.; Basset, A.; Kore, K.; Hargraves, Z.; Peterson, T.

    2005-12-01

    During June and July of 2005, the Plate Boundary Observatory (PBO) installed eight permanent GPS stations on Akutan Volcano, in the central Aleutian Islands of Alaska. PBO worked closely with the Alaska Volcano Observatory and the Magmatic Systems Site Selection working group to install stations with a spatial distribution to monitor and detect both short and long term volcanic deformation in response to magmatic intrusions at depth and magma migration through the volcano's conduit system. All eight of the GPS stations were installed by PBO field crews with helicopter support provided by Evergreen Helicopters and logistical support from the Trident Seafood Corporation, the City of Akutan, and the Akutan Corporation. Lack of roads and drivable trails on the remote volcanic island required that all equipment be transported to each site from the village of Akutan by slinging gear beneath the helicopter and internal loads. Each station installed on the volcano consists of a standard short braced GPS monument, two solar panels mounted to an inclined structure, and a six foot high Plaschem enclosure with two solar panels mounted to one of the inclined sides. Each Plaschem houses 24 6 volt batteries that power a Trimble NetRS GPS receiver and one or two Intuicom radios. Data from each GPS receiver is telemetered directly or through a repeater radio to a base station located in the village of Akutan that transmits the data over the internet to the UNAVCO data archive at ftp://data-out.unavco.or/pub/PBO_rinex where it is made freely available to the public.

  20. The USGS Hawaiian Volcano Observatory Monitors Kilauea's Summit Eruption

    The USGS Hawaiian Volcano Observatory (foreground) is located on the caldera rim of Kilauea Volcano, Hawai'i—the most active volcano in the world.  The observatory's location provides an excellent view of summit eruptive activity, which began in 2008....

  1. Decision Analysis Tools for Volcano Observatories

    NASA Astrophysics Data System (ADS)

    Hincks, T. H.; Aspinall, W.; Woo, G.

    2005-12-01

    Staff at volcano observatories are predominantly engaged in scientific activities related to volcano monitoring and instrumentation, data acquisition and analysis. Accordingly, the academic education and professional training of observatory staff tend to focus on these scientific functions. From time to time, however, staff may be called upon to provide decision support to government officials responsible for civil protection. Recognizing that Earth scientists may have limited technical familiarity with formal decision analysis methods, specialist software tools that assist decision support in a crisis should be welcome. A review is given of two software tools that have been under development recently. The first is for probabilistic risk assessment of human and economic loss from volcanic eruptions, and is of practical use in short and medium-term risk-informed planning of exclusion zones, post-disaster response, etc. A multiple branch event-tree architecture for the software, together with a formalism for ascribing probabilities to branches, have been developed within the context of the European Community EXPLORIS project. The second software tool utilizes the principles of the Bayesian Belief Network (BBN) for evidence-based assessment of volcanic state and probabilistic threat evaluation. This is of practical application in short-term volcano hazard forecasting and real-time crisis management, including the difficult challenge of deciding when an eruption is over. An open-source BBN library is the software foundation for this tool, which is capable of combining synoptically different strands of observational data from diverse monitoring sources. A conceptual vision is presented of the practical deployment of these decision analysis tools in a future volcano observatory environment. Summary retrospective analyses are given of previous volcanic crises to illustrate the hazard and risk insights gained from use of these tools.

  2. Satellite monitoring of remote volcanoes improves study efforts in Alaska

    NASA Astrophysics Data System (ADS)

    Dean, K.; Servilla, M.; Roach, A.; Foster, B.; Engle, K.

    Satellite monitoring of remote volcanoes is greatly benefitting the Alaska Volcano Observatory (AVO), and last year's eruption of the Okmok Volcano in the Aleutian Islands is a good case in point. The facility was able to issue and refine warnings of the eruption and related activity quickly, something that could not have been done using conventional seismic surveillance techniques, since seismometers have not been installed at these locations.AVO monitors about 100 active volcanoes in the North Pacific (NOPAC) region, but only a handful are observed by costly and logistically complex conventional means. The region is remote and vast, about 5000 × 2500 km, extending from Alaska west to the Kamchatka Peninsula in Russia (Figure 1). Warnings are transmitted to local communities and airlines that might be endangered by eruptions. More than 70,000 passenger and cargo flights fly over the region annually, and airborne volcanic ash is a threat to them. Many remote eruptions have been detected shortly after the initial magmatic activity using satellite data, and eruption clouds have been tracked across air traffic routes. Within minutes after eruptions are detected, information is relayed to government agencies, private companies, and the general public using telephone, fax, and e-mail. Monitoring of volcanoes using satellite image data involves direct reception, real-time monitoring, and data analysis. Two satellite data receiving stations, located at the Geophysical Institute, University of Alaska Fairbanks (UAF), are capable of receiving data from the advanced very high resolution radiometer (AVHRR) on National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites and from synthetic aperture radar (SAR) equipped satellites.

  3. Hawaiian Volcano Observatory 1956 Quarterly Administrative Reports

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. This report consists of four parts.

  4. Alaska - Russian Far East connection in volcano research and monitoring

    NASA Astrophysics Data System (ADS)

    Izbekov, P. E.; Eichelberger, J. C.; Gordeev, E.; Neal, C. A.; Chebrov, V. N.; Girina, O. A.; Demyanchuk, Y. V.; Rybin, A. V.

    2012-12-01

    The Kurile-Kamchatka-Alaska portion of the Pacific Rim of Fire spans for nearly 5400 km. It includes more than 80 active volcanoes and averages 4-6 eruptions per year. Resulting ash clouds travel for hundreds to thousands of kilometers defying political borders. To mitigate volcano hazard to aviation and local communities, the Alaska Volcano Observatory (AVO) and the Institute of Volcanology and Seismology (IVS), in partnership with the Kamchatkan Branch of the Geophysical Survey of the Russian Academy of Sciences (KBGS), have established a collaborative program with three integrated components: (1) volcano monitoring with rapid information exchange, (2) cooperation in research projects at active volcanoes, and (3) volcanological field schools for students and young scientists. Cooperation in volcano monitoring includes dissemination of daily information on the state of volcanic activity in neighboring regions, satellite and visual data exchange, as well as sharing expertise and technologies between AVO and the Kamchatkan Volcanic Eruption Response Team (KVERT) and Sakhalin Volcanic Eruption Response Team (SVERT). Collaboration in scientific research is best illustrated by involvement of AVO, IVS, and KBGS faculty and graduate students in mutual international studies. One of the most recent examples is the NSF-funded Partnerships for International Research and Education (PIRE)-Kamchatka project focusing on multi-disciplinary study of Bezymianny volcano in Kamchatka. This international project is one of many that have been initiated as a direct result of a bi-annual series of meetings known as Japan-Kamchatka-Alaska Subduction Processes (JKASP) workshops that we organize together with colleagues from Hokkaido University, Japan. The most recent JKASP meeting was held in August 2011 in Petropavlovsk-Kamchatsky and brought together more than 130 scientists and students from Russia, Japan, and the United States. The key educational component of our collaborative program is the continuous series of international volcanological field schools organized in partnership with the Kamchatka State University. Each year more than 40 students and young scientists participate in our annual field trips to Katmai, Alaska and Mutnovsky, Kamchatka.

  5. Interferometric Synthetic Aperture radar studies of Alaska volcanoes

    USGS Publications Warehouse

    Lu, Zhong; Wicks, Charles W., Jr.; Dzurisin, Daniel; Power, John A.; Thatcher, Wayne R.; Masterlark, Timothy

    2003-01-01

    In this article, we summarize our recent InSAR studies of 13 Alaska volcanoes, including New Trident, Okmok, Akutan, Kiska, Augustine, Westdahl, Peulik, Makushin, Seguam, Shishaldin, Pavlof, Cleveland, and Korovin volcanoes.

  6. Monitoring and imaging Alaska volcanoes using seismic noise

    NASA Astrophysics Data System (ADS)

    Haney, M. M.

    2007-12-01

    The utility of ambient seismic noise for monitoring and imaging the subsurface has implications for the understanding of volcanic systems and processes. Recent studies have demonstrated that the cross-correlation of continuous seismic noise recordings at two stations yields portions of the impulse response, or Green's function. The impulse response is the data which would have been recorded had a controlled seismic source been activated at one of the stations and the resulting seismic waves measured at the other station. The idea of cross-correlating seismic noise can be traced back to the spatial auto-correlation (SPAC) method first introduced by Keiiti Aki in 1957. In contrast to the SPAC method, contemporary studies have popularized the use of temporal cross-correlations between pairs of seismic stations. We have conducted an initial study into the use of seismic noise for imaging at Mount Spurr volcano, located 100 km west of Anchorage, Alaska. In part because of its proximity to Anchorage, Mount Spurr is one of the most densely instrumented volcanoes in the network run by the Alaska Volcano Observatory, with three permanent broadband and thirteen short period stations. In addition, data from eight broadband stations exist from a temporary deployment during three months in the summer of 2005. The complete data set, including permanent/temporary and broadband/short period stations, provides good station coverage and makes surface wave tomography using cross-correlated seismic noise recordings feasible at Mount Spurr. Preliminary surface wave tomograms at 2 s period give indications of an aseismic fault to the east of Mount Spurr. We have also applied the cross-correlation technique at other Alaska volcanoes, including Augustine, Iliamna, and the currently erupting Pavlof, as well as a subset of short period data from the network in and around the East Rift Zone operated by the Hawaiian Volcano Observatory. Results at Iliamna demonstrate the variability in the direction of ocean-generated noise over time due to storms in the Gulf of Alaska and the Chukchi Sea. These different data sets give indications of how the cross-correlation method performs in varied noise conditions and geologic settings.

  7. Hawaiian Volcano Observatory 1976 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  8. Hawaiian Volcano Observatory 1977 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  9. Hawaiian Volcano Observatory 1979 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  10. Hawaiian Volcano Observatory 1980 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  11. Hawaiian Volcano Observatory 1970 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  12. Hawaiian Volcano Observatory 1961 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  13. Hawaiian Volcano Observatory 1969 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  14. Hawaiian Volcano Observatory 1975 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  15. Hawaiian Volcano Observatory 1985 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  16. Hawaiian Volcano Observatory 1957 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  17. Hawaiian Volcano Observatory 1972 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  18. Hawaiian Volcano Observatory 1963 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  19. Hawaiian Volcano Observatory 1971 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  20. Hawaiian Volcano Observatory 1983 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  1. Hawaiian Volcano Observatory 1978 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  2. Hawaiian Volcano Observatory 1968 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  3. Hawaiian Volcano Observatory 1965 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  4. Hawaiian Volcano Observatory 1966 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  5. Hawaiian Volcano Observatory 1973 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  6. Hawaiian Volcano Observatory 1974 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  7. Hawaiian Volcano Observatory 1962 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  8. Hawaiian Volcano Observatory 1981 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  9. Hawaiian Volcano Observatory 1967 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  10. Hawaiian Volcano Observatory 1964 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  11. Hawaiian Volcano Observatory 1984 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  12. Hawaiian Volcano Observatory 1960 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  13. Hawaiian Volcano Observatory 1959 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  14. Hawaiian Volcano Observatory 1958 Quarterly Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  15. Hawaiian Volcano Observatory 1982 Annual Administrative Report

    USGS Publications Warehouse

    Nakata, Jennifer S., (compiler)

    2007-01-01

    INTRODUCTORY NOTE The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to the present are now available as .pdf files at http://www.usgs.gov/pubprod. The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are published separately, due to differing schedules of data reduction. There are eight quarters - from the fourth quarter of 1959 to the third quarter of 1961 - that were never published. Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton (HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

  16. Three Short Videos by the Yellowstone Volcano Observatory

    USGS Publications Warehouse

    Wessells, Stephen; Lowenstern, Jake; Venezky, Dina

    2009-01-01

    This is a collection of videos of unscripted interviews with Jake Lowenstern, who is the Scientist in Charge of the Yellowstone Volcano Observatory (YVO). YVO was created as a partnership among the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety. These video presentations give insights about many topics of interest about this area. Title: Yes! Yellowstone is a Volcano An unscripted interview, January 2009, 7:00 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions to explain volcanic features at Yellowstone: 'How do we know Yellowstone is a volcano?', 'What is a Supervolcano?', 'What is a Caldera?','Why are there geysers at Yellowstone?', and 'What are the other geologic hazards in Yellowstone?' Title: Yellowstone Volcano Observatory An unscripted interview, January 2009, 7:15 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions about the Yellowstone Volcano Observatory: 'What is YVO?', 'How do you monitor volcanic activity at Yellowstone?', 'How are satellites used to study deformation?', 'Do you monitor geysers or any other aspect of the Park?', 'Are earthquakes and ground deformation common at Yellowstone?', 'Why is YVO a relatively small group?', and 'Where can I get more information?' Title: Yellowstone Eruptions An unscripted interview, January 2009, 6.45 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions to explain volcanic eruptions at Yellowstone: When was the last supereruption at Yellowstone?', 'Have any eruptions occurred since the last supereruption?', 'Is Yellowstone overdue for an eruption?', 'What does the magma below indicate about a possible eruption?', 'What else is possible?', and 'Why didn't you think the Yellowstone Lake earthquake swarm would lead to an eruption?'

  17. Augustine Volcano, Cook Inlet, Alaska (January 31, 2006)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Since last spring, the U.S. Geological Survey's Alaska Volcano Observatory (AVO) has detected increasing volcanic unrest at Augustine Volcano in Cook Inlet, Alaska near Anchorage. Based on all available monitoring data, AVO regards that an eruption similar to 1976 and 1986 is the most probable outcome. During January, activity has been episodic, and characterized by emission of steam and ash plumes, rising to altitudes in excess of 9,000 m (30,000 ft), and posing hazards to aircraft in the vicinity. In the last week, volcanic flows have been seen on the volcano's flanks. An ASTER thermal image was acquired at night at 22:50 AST on January 31, 2006, during an eruptive phase of Augustine. The image shows three volcanic flows down the north flank of Augustine as white (hot) areas. The eruption plume spreads out to the east in a cone shape: it appears dark blue over the summit because it is cold and water ice dominates the composition; further downwind a change to orange color indicates that the plume is thinning and the signal is dominated by the presence of ash.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 54 by 51.9 km (33.5 by 32.1 miles) Location: 59.3 deg. North latitude, 153.4 deg. West longitude Orientation: north to top Resolution: 90 m ASTER Date Acquired: January 31, 2006

  18. Chasing lava: a geologist's adventures at the Hawaiian Volcano Observatory

    USGS Publications Warehouse

    Duffield, Wendell A.

    2003-01-01

    A lively account of the three years (1969-1972) spent by geologist Wendell Duffield working at the Hawaiian Volcano Observatory at Kilauea, one of the world's more active volcanoes. Abundantly illustrated in b&w and color, with line drawings and maps, as well. Volcanologists and general readers alike will enjoy author Wendell Duffield's report from Kilauea--home of Pele, the goddess of fire and volcanoes. Duffield's narrative encompasses everything from the scientific (his discovery that the movements of cooled lava on a lava lake mimic the movements of the earth's crust, providing an accessible model for understanding plate tectonics) to the humorous (his dog's discovery of a snake on the supposedly snake-free island) to the life-threatening (a colleague's plunge into molten lava). This charming account of living and working at Kilauea, one of the world's most active volcanoes, is sure to be a delight.

  19. Satellite Observations of Volcanic Clouds from the Eruption of Redoubt Volcano, Alaska, 2009

    NASA Astrophysics Data System (ADS)

    Dean, K. G.; Ekstrand, A. L.; Webley, P.; Dehn, J.

    2009-12-01

    Redoubt Volcano began erupting on 23 March 2009 (UTC) and consisted of 19 events over a 14 day period. The volcano is located on the Alaska Peninsula, 175 km southwest of Anchorage, Alaska. The previous eruption was in 1989/1990 and seriously disrupted air traffic in the region, including the near catastrophic engine failure of a passenger airliner. Plumes and ash clouds from the recent eruption were observed on a variety of satellite data (AVHRR, MODIS and GOES). The eruption produced volcanic clouds up to 19 km which are some of the highest detected in recent times in the North Pacific region. The ash clouds primarily drifted north and east of the volcano, had a weak ash signal in the split window data and resulted in light ash falls in the Cook Inlet basin and northward into Alaskas Interior. Volcanic cloud heights were measured using ground-based radar, and plume temperature and wind shear methods but each of the techniques resulted in significant variations in the estimates. Even though radar showed the greatest heights, satellite data and wind shears suggest that the largest concentrations of ash may be at lower altitudes in some cases. Sulfur dioxide clouds were also observed on satellite data (OMI, AIRS and Calipso) and they primarily drifted to the east and were detected at several locations across North America, thousands of kilometers from the volcano. Here, we show time series data collected by the Alaska Volcano Observatory, illustrating the different eruptive events and ash clouds that developed over the subsequent days.

  20. Repeating coupled earthquakes at Shishaldin Volcano, Alaska

    USGS Publications Warehouse

    Caplan-Auerbach, J.; Petersen, T.

    2005-01-01

    Since it last erupted in 1999, Shishaldin Volcano, Aleutian Islands, Alaska, has produced hundreds to thousands of long-period (1-2 Hz; LP) earthquakes every day with no other sign of volcanic unrest. In 2002, the earthquakes also exhibited a short-period (4-7 Hz; SP) signal occurring between 3 and 15 s before the LP phase. Although the SP phase contains higher frequencies than the LP phase, its spectral content is still well below that expected of brittle failure events. The SP phase was never observed without the LP phase, although LP events continued to occur in the absence of the precursory signal. The two-phased events are termed "coupled events", reflecting a triggered relationship between two discrete event types. Both phases are highly repetitive in time series, suggestive of stable, non-destructive sources. Waveform cross-correlation and spectral coherence are used to extract waveforms from the continuous record and determine precise P-wave arrivals for the SP phase. Although depths are poorly constrained, the SP phase is believed to lie at shallow (<4 km) depths just west of Shishaldin's summit. The variable timing between the SP and LP arrivals indicates that the trigger mechanism between the phases itself moves at variable speeds. A model is proposed in which the SP phase results from fluid moving within the conduit, possibly around an obstruction and the LP phase results from the coalescence of a shallow gas bubble. The variable timing is attributed to changes in gas content within the conduit. The destruction of the conduit obstacle on November 21, 2002 resulted in the abrupt disappearance of the SP phase.

  1. The final year of GPS Installations in the Alaska Region of the Plate Boundary Observatory

    NASA Astrophysics Data System (ADS)

    Coyle, B.; Pauk, B.; Enders, M.; Bierma, R.; Gasparich, S.; Marzulla, A.; Feaux, K.

    2008-12-01

    The Plate Boundary Observatory (PBO) is the geodetic component of the National Science Foundation funded Earthscope Project. The final PBO GPS network will comprise 1100 continuously operating GPS stations installed throughout the Western US and Alaska. The Alaska region is an important area of study because of the major crustal deformation and high volcanic activity associated with the subduction of the Pacific Plate beneath the North American Plate. The PBO network will provide data to help better understand these earth processes. In the fifth and final year of the PBO installation phase, we built 31 GPS Stations and installed 8 tilt meters in Alaska. These installs completed the PBO network in Alaska which comprises 135 GPS stations and 12 tilt meters. We also completed maintenance visits to GPS stations installed during earlier years of the five year project. In the 2008 field season we faced some of our most difficult logistical challenges with installations in remote areas, islands and volcanoes. Highlights include boat-based helicopter supported installs in the Shumagin Islands on Chernabura, Nagai and Popof; and 13 GPS stations and 8 tiltmeters installed on Unimak Island to monitor Westdahl and Shishaldin volcanoes. The Unimak installations were completed in a four week period and were carried out in cooperation with scientists from the Alaska Volcano Observatory. We also installed the remaining stations monitoring the Denali fault and integrated the Denali earthquake response stations built by University of Alaska Fairbanks into the PBO network. Now that the installations are completed, the PBO network will be operated and maintained by UNAVCO engineers for the next 10 years. Data from all of the PBO stations are available from the UNAVCO archive.

  2. Seismicity and structure of Akutan and Makushin Volcanoes, Alaska, using joint body and surface wave tomography

    DOE PAGESBeta

    Syracuse, E. M.; Maceira, M.; Zhang, H.; Thurber, C. H.

    2015-02-18

    Joint inversions of seismic data recover models that simultaneously fit multiple constraints while playing upon the strengths of each data type. Here, we jointly invert 14 years of local earthquake body wave arrival times from the Alaska Volcano Observatory catalog and Rayleigh wave dispersion curves based upon ambient noise measurements for local Vp, Vs, and hypocentral locations at Akutan and Makushin Volcanoes using a new joint inversion algorithm.The velocity structure and relocated seismicity of both volcanoes are significantly more complex than many other volcanoes studied using similar techniques. Seismicity is distributed among several areas beneath or beyond the flanks ofmore » both volcanoes, illuminating a variety of volcanic and tectonic features. The velocity structures of the two volcanoes are exemplified by the presence of narrow high-Vp features in the near surface, indicating likely current or remnant pathways of magma to the surface. A single broad low-Vp region beneath each volcano is slightly offset from each summit and centered at approximately 7 km depth, indicating a potential magma chamber, where magma is stored over longer time periods. Differing recovery capabilities of the Vp and Vs datasets indicate that the results of these types of joint inversions must be interpreted carefully.« less

  3. Seismicity and structure of Akutan and Makushin Volcanoes, Alaska, using joint body and surface wave tomography

    SciTech Connect

    Syracuse, E. M.; Maceira, M.; Zhang, H.; Thurber, C. H.

    2015-02-18

    Joint inversions of seismic data recover models that simultaneously fit multiple constraints while playing upon the strengths of each data type. Here, we jointly invert 14 years of local earthquake body wave arrival times from the Alaska Volcano Observatory catalog and Rayleigh wave dispersion curves based upon ambient noise measurements for local Vp, Vs, and hypocentral locations at Akutan and Makushin Volcanoes using a new joint inversion algorithm.The velocity structure and relocated seismicity of both volcanoes are significantly more complex than many other volcanoes studied using similar techniques. Seismicity is distributed among several areas beneath or beyond the flanks of both volcanoes, illuminating a variety of volcanic and tectonic features. The velocity structures of the two volcanoes are exemplified by the presence of narrow high-Vp features in the near surface, indicating likely current or remnant pathways of magma to the surface. A single broad low-Vp region beneath each volcano is slightly offset from each summit and centered at approximately 7 km depth, indicating a potential magma chamber, where magma is stored over longer time periods. Differing recovery capabilities of the Vp and Vs datasets indicate that the results of these types of joint inversions must be interpreted carefully.

  4. The 2013 Eruptions of Pavlof and Mount Veniaminof Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Waythomas, C. F.; Wallace, K.; Haney, M. M.; Fee, D.; Pavolonis, M. J.; Read, C.

    2013-12-01

    Pavlof Volcano and Mount Veniaminof on the Alaska Peninsula erupted during the summer of 2013 and were monitored by the Alaska Volcano Observatory (AVO) using seismic data, satellite and web camera images, a regional infrasound array and observer reports. An overview of the work of the entire AVO staff is presented here. The 2013 eruption of Pavlof Volcano began on May 13 after a brief and subtle period of precursory seismicity. Two volcano-tectonic (VT) earthquakes at depths of 6-8 km on April 24 preceded the onset of the eruption by 3 weeks. Given the low background seismicity at Pavlof, the VTs were likely linked to the ascent of magma. The onset of the eruption was marked by subtle pulsating tremor that coincided with elevated surface temperatures in satellite images. Activity during May and June was characterized by lava fountaining and effusion from a vent near the summit. Seismicity consisted of fluctuating tremor and numerous explosions that were detected on an infrasound array (450 km NE) and as ground-coupled airwaves at local and distant seismic stations (up to 650 km). Emissions of ash and sulfur dioxide were observed in satellite data extending as far as 300 km downwind at altitudes of 5-7 km above sea level. Ash collected in Sand Point (90 km E) were well sorted, 60-150 micron diameter juvenile glass shards, many of which had fluidal forms. Automated objective ash cloud detection and cloud height retrievals from the NOAA volcanic cloud alerting system were used to evaluate the hazard to aviation. A brief reconnaissance of Pavlof in July found that lava flows on the NW flank consist of rubbly, clast rich, 'a'a flows composed of angular blocks of agglutinate and rheomorphic lava. There are at least three overlapping flows, the longest of which extends about 5 km from the vent. Eruptive activity continued through early July, and has since paused or stopped. Historical eruptions of Mount Veniaminof volcano have been from an intracaldera cone within a 10-km summit caldera. Subtle pulsating tremor also signaled unrest at Veniaminof on June 7, a week prior to satellite observations of elevated surface temperatures within the caldera that indicated the presence of lava at the surface. Eruptive activity consisted of lava fountaining and effusion, and numerous explosive events that produced small ash clouds that typically reached only several hundred meters above the vent, and rarely were observed extending beyond the summit caldera. Seismicity was characterized by energetic tremor, and accompanied at times by numerous explosions that were heard by local residents at distances of 20-50 km, and detected as ground coupled airwaves at distant seismic stations (up to 200 km) and by an infrasound array (350 km distance). Because infrasound can propagate over great distances with little signal degradation or distortion, it was possible to correlate the ground-coupled airwaves between seismometers separated by 100's of km and thus identify their source. A helicopter fly over in July found that lava flows erupted from the intracaldera cone consist of 3-5 small lobes of rubbly spatter-rich lava up to 800 m in length on the southwest flank of the cone. The distal ends of the flows melted snow and ice adjacent to the cone to produce a water-rich plume, but there was no evidence for outflow of water from the caldera. Volcanic unrest has continued through early August, 2013.

  5. Preliminary Geology of Gareloi Volcano, Western Aleutian Islands (Alaska)

    NASA Astrophysics Data System (ADS)

    Browne, B. L.; Coombs, M.; Larsen, J.

    2004-12-01

    Gareloi Island consists of Gareloi volcano (1573 m elevation), and is located nearly 2000 km west of Anchorage and 120 km west of Adak in the western Aleutian (Andreanof) Islands. A geologic mapping operation was combined with the installation of a seismic monitoring network in September of 2003 by the Alaska Volcano Observatory. This work provided the first direct observations of Gareloi volcano since Robert Coats' four-day visit in 1945. Gareloi volcano is a stratovolcano 10 km by 8 km in diameter at its base with two summit craters separated by a narrow saddle. The southern crater is a 300-m-wide amphitheater formed by the partial collapse of its southern crater wall, and contains several active fumaroles. The northern crater is enclosed, although the intra-crater eruptive stratigraphy is abruptly interrupted by near-vertical local unconformities on the northwest wall, suggesting the occurrence of a sector collapse sometime in the past. Gareloi volcano is principally composed of intercalated trachytic lava flows, ranging from 0.5 m to more than 10 m in thickness. Two prominent valleys composed of thick lava flow packages on the SW flank are clearly U-shaped, suggesting that the oldest sequence of lava flows is of at least late Pleistocene age. Lavas erupted during the Pleistocene and Holocene range from basaltic trachyandesite to basaltic andesite in composition and contain plagioclase and clinopyroxene, with minor olivine, and rare hornblende. An explosive eruption in 1929 formed a SSE trending fissure of thirteen aligned craters, ranging from 80 to 1600 m in diameter. These craters extend from sea level up to the amphitheater of the southern crater (1160 m). Fall deposits from the 1929 eruption are interbedded with thin, laterally discontinuous pyroclastic flow deposits that are mainly limited to the island's southeastern flanks. Despite an abrupt change in color from light beige pumice clasts at the base of the 1929 fall deposit to black scoria at the top, the unit is homogeneous trachyandesite. Following the explosive phase of the eruption, 4 blocky trachyandesite lava flows emerged from craters below 600 m asl. All 1929 eruptive products contain plagioclase and clinopyroxene with scarce olivine. An effusive eruption during the 1980's from the center of the south crater amphitheater produced an elaborate blocky lava flow that extends 800 m in elevation down the SE flank. This lava flow is basaltic trachyandesite, and contains abundant coarsely sieved plagioclase phenocrysts with minor clinopyroxene and olivine. The majority of Gareloi lavas contain anomalously high concentrations of K, Na, and Rb and low concentrations of Mg compared to reported findings from other Aleutian lavas, including those of the western portion of the arc. This suggests that Gareloi magmas may be unique with respect to their source region and possibly storage conditions compared to other Aleutian volcanoes.

  6. Augustine Volcano, Cook Inlet, Alaska (January 12, 2006)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Since last spring, the U.S. Geological Survey's Alaska Volcano Observatory (AVO) has detected increasing volcanic unrest at Augustine Volcano in Cook Inlet, Alaska near Anchorage. Based on all available monitoring data, AVO regards that an eruption similar to 1976 and 1986 is the most probable outcome. During January, activity has been episodic, and characterized by emission of steam and ash plumes, rising to altitudes in excess of 9,000 m (30,000 ft), and posing hazards to aircraft in the vicinity. An ASTER image was acquired at 12:42 AST on January 12, 2006, during an eruptive phase of Augustine. The perspective rendition shows the eruption plume derived from the ASTER image data. ASTER's stereo viewing capability was used to calculate the 3-dimensional topography of the eruption cloud as it was blown to the south by prevailing winds. From a maximum height of 3060 m (9950 ft), the plume cooled and its top descended to 1900 m (6175 ft). The perspective view shows the ASTER data draped over the plume top topography, combined with a base image acquired in 2000 by the Landsat satellite, that is itself draped over ground elevation data from the Shuttle Radar Topography Mission. The topographic relief has been increased 1.5 times for this illustration. Comparison of the ASTER plume topography data with ash dispersal models and weather radar data will allow the National Weather Service to validate and improve such models. These models are used to forecast volcanic ash plume trajectories and provide hazard alerts and warnings to aircraft in the Alaska region.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: Roughly 25 km (15 miles) across; scale varies in this perspective view Location: 59.3 deg. North latitude, 153.4 deg. West longitude Orientation: View from southwest towards the northeast Vertical Exaggeration: 2 Eruption plume and Elevation: 30 m ASTER, (1-arcsecond) Image Data: Landsat bands 7, 4 and 2 Ground Topography Data: SRTM 90 m data, acquired January 2000 Date Acquired: ASTER: January 12, 2006; Landsat: September 17, 2000

  7. Examining 2008 Eruption of Okmok Volcano in Alaska

    Professor Michael Ort (Northern Arizona University) and graduate student Joel Unema examine deposits from the 2008 eruption of Okmok volcano in Alaska as part of their research to reconstruct the complex history of the eruption.  Dr. Ort has an ARRA-funded cooperative agreement with the USGS th...

  8. Chasing Lava: A Geologist's Adventures at the Hawaiian Volcano Observatory

    NASA Astrophysics Data System (ADS)

    Varekamp, Johan C.

    2004-01-01

    Many popular volcano books have appeared over the last few years; for example, Vulcan's Fury by A. Scarth, Melting the Earth by H. Sigurdsson, and Volcanoes in Human History by J.Z. deBoer and D.T. Sanders. All of these books have their own qualities. Duffield's Chasing Lava-A Geologist's Adventures at the Hawaiian Volcano Observatory stands apart from that crowded field and is comparable to Out of the Crater by R.V. Fisher. The book presents a very personal view of volcanology, erupting volcanoes, and what it means to be part of a team that investigates them. The author mixes scientific observations with accounts of the grandeur of Hawaii, musings about his own personal life 30 years ago, and the pleasure that one derives from working in an organization like the Hawaiian Volcano Observatory (HVO) on a gorgeous tropical island. The book starts out with the history of the HVO and the accomplishments of T.A. Jaggar as scientist-in-charge. The author then gives accounts of his own work on Hawaii and introduces the reader to, among other topics, tilt measurements and laser reflector instruments. He discusses the search for fresh water on the island, and notes that the need for clean water ultimately may become one of the most pressing issues of this island world. He alternates between descriptions of geological features with great photographic close-ups of flowing lavas, and narrow escapes; and casually introduces fundamental geological perspectives in the process. Most geologists are familiar with Duffield's ideas about the shifting plates on the surface of Mauna Ulu lava lake as an analog of global plate movements. I was not aware of his experiments with bastnaesite-doping of the magma to add a La-rich tracer to the magma to track its lateral flow, but in this book readers learn about both.

  9. Bibliography for Hayes, Spurr, Crater Peak, Redoubt, Iliamna, Augustine, Douglas, and Aniakchak volcanoes, Alaska

    USGS Publications Warehouse

    Lemke, K.J.; May, B.A.; Vanderpool, A.M.

    1995-01-01

    Alaska has more than 40 active volcanoes, many of which are close to the major population centers of south-central Alaska. This bibliography was compiled to assist in the preparation of volcano hazard evaluations at Cook Inlet volcanoes. It lists articles, reports, and maps about the geology and hydrology of Hayes, Spurr, Redoubt, Iliamna, Augustine, and Douglas volcanoes in the Cook Inlet region as well as Aniakchak Volcano on the Alaska Peninsula. References on the biology and archaeology of areas surrounding each volcano also are included because they may provide useful background information.

  10. New Coastal Tsunami Gauges: Application at Augustine Volcano, Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Burgy, M.; Bolton, D. K.

    2006-12-01

    Recent eruptive activity at Augustine Volcano and its associated tsunami threat to lower Cook Inlet pointed out the need for a quickly deployable tsunami detector which could be installed on Augustine Island's coast. The detector's purpose would be to verify tsunami generation by direct observation of the wave at the source to support tsunami warning decisions along populated coastlines. To fill this need the Tsunami Mobile Alert Real-Time (TSMART) system was developed at NOAA's West Coast/Alaska Tsunami Warning Center with support from the University of Alaska Tsunami Warning and Environmental Observatory for Alaska program (TWEAK) and the Alaska Volcano Observatory (AVO). The TSMART system consists of a pressure sensor installed as near as possible to the low tide line. The sensor is enclosed in a water-tight hypalon bag filled with propylene-glycol to prevent silt damage to the sensor and freezing. The bag is enclosed in a perforated, strong plastic pipe about 16 inches long and 8 inches in diameter enclosed at both ends for protection. The sensor is cabled to a data logger/radio/power station up to 300 feet distant. Data are transmitted to a base station and made available to the warning center in real-time through the internet. This data telemetry system can be incorporated within existing AVO and Plate Boundary Observatory networks which makes it ideal for volcano-tsunami monitoring. A TSMART network can be utilized anywhere in the world within 120 miles of an internet connection. At Augustine, two test stations were installed on the east side of the island in August 2006. The sensors were located very near the low tide limit and covered with rock, and the cable was buried to the data logger station which was located well above high tide mark. Data logger, radio, battery and other electronics are housed in an enclosure mounted to a pole which also supports an antenna and solar panel. Radio signal is transmitted to a repeater station higher up on the island which then transmits the data to a base station in Homer, Alaska. Sea level data values are transmitted every 15 seconds and displayed at the tsunami warning center in Palmer, Alaska.

  11. Geodetic evidence for lower crustal magma withdrawal during the 2009 eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Cervelli, P. F.; Grapenthin, R.; Freymueller, J. T.

    2009-12-01

    Redoubt volcano, on the western side of Cook Inlet about 100 miles WSW of Anchorage, Alaska began erupting in March 2009. The eruption continued for nearly 3 months, and slow dome growth may still persist. No continuously recording GPS instrumentation existed with 25 km of Redoubt at the beginning of major precursory unrest in January 2009. The closest CPGS instrument at that time was the Plate Boundary Observatory (PBO) backbone station AC17, about 27 km northeast of the volcano's summit. A small GPS campaign network, consisting of about 15 benchmarks, had been established at Redoubt in 2001 and had been partially reoccupied in 2008. In response to the precursory unrest, the Alaska Volcano Observatory deployed continuously recording GPS instruments at five of the campaign benchmarks, though only one of these was telemetered. Several distinct signals appear in the GPS time series, suggesting an interplay of at least two sources ranging in depth from the lower crust to within the volcanic edifice. The most remarkable of these signals, measured more than 25 km from Redoubt at AC17, shows a movement down and toward the volcano coincident in time with the initial onset of extrusion in late March, but ending well before the emplacement of the large, 70 million cubic meter lava dome through mid-April to mid-May that culminated the eruption. Closer stations show an exponentially decaying pattern of deflation that seems to follow the temporal pattern of dome growth. These contrasting styles and scales of deformation almost certainly indicate multiple sources operating over a range of depths. The rapid augmentation of the Redoubt geophysical network with CGPS proved quite useful, not just from the standpoint of engendering scientific research, but also from the perspective of providing short-term forecasts of volcanic hazard. As demonstrated during the recent eruption of Redoubt, as well as at other volcanoes in Alaska and elsewhere, we argue that routine use of CGPS on stratovolcanoes is an investment well worth making. The initial outlay of funding, logistics, and general effort involved with building CGPS instrumentation and telemetry infrastructure has now paid off handsomely at three volcanoes in the last five years: Augustine in 2006, Okmok in 2008, and now Redoubt in 2009. Of course, experience has shown that deploying CGPS instrumentation before unrest, as at Augustine and Okmok, is vastly preferable to a hasty after-the-fact deployment, which is inevitably more dangerous to install, subject to much more inflexible logistical constraints, and is likely to image only a fraction of the total deformation signal in evidence over the entirety of an eruption.

  12. Database for volcanic processes and geology of Augustine Volcano, Alaska

    USGS Publications Warehouse

    McIntire, Jacqueline; Ramsey, David W.; Thoms, Evan; Waitt, Richard B.; Beget, James E.

    2012-01-01

    This digital release contains information used to produce the geologic map published as Plate 1 in U.S. Geological Survey Professional Paper 1762 (Waitt and Begét, 2009). The main component of this digital release is a geologic map database prepared using geographic information systems (GIS) applications. This release also contains links to files to view or print the map plate, accompanying measured sections, and main report text from Professional Paper 1762. It should be noted that Augustine Volcano erupted in 2006, after the completion of the geologic mapping shown in Professional Paper 1762 and presented in this database. Information on the 2006 eruption can be found in U.S. Geological Survey Professional Paper 1769. For the most up to date information on the status of Alaska volcanoes, please refer to the U.S. Geological Survey Volcano Hazards Program website.

  13. NGEE Arctic Webcam Photographs, Barrow Environmental Observatory, Barrow, Alaska

    DOE Data Explorer

    Bob Busey; Larry Hinzman

    2012-04-01

    The NGEE Arctic Webcam (PTZ Camera) captures two views of seasonal transitions from its generally south-facing position on a tower located at the Barrow Environmental Observatory near Barrow, Alaska. Images are captured every 30 minutes. Historical images are available for download. The camera is operated by the U.S. DOE sponsored Next Generation Ecosystem Experiments - Arctic (NGEE Arctic) project.

  14. Preliminary volcano-hazard assessment for Akutan Volcano east-central Aleutian Islands, Alaska

    USGS Publications Warehouse

    Waythomas, Christopher F.; Power, John A.; Richter, Donlad H.; McGimsey, Robert G.

    1998-01-01

    Akutan Volcano is a 1100-meter-high stratovolcano on Akutan Island in the east-central Aleutian Islands of southwestern Alaska. The volcano is located about 1238 kilometers southwest of Anchorage and about 56 kilometers east of Dutch Harbor/Unalaska. Eruptive activity has occurred at least 27 times since historical observations were recorded beginning in the late 1700?s. Recent eruptions produced only small amounts of fine volcanic ash that fell primarily on the upper flanks of the volcano. Small amounts of ash fell on the Akutan Harbor area during eruptions in 1911, 1948, 1987, and 1989. Plumes of volcanic ash are the primary hazard associated with eruptions of Akutan Volcano and are a major hazard to all aircraft using the airfield at Dutch Harbor or approaching Akutan Island. Eruptions similar to historical Akutan eruptions should be anticipated in the future. Although unlikely, eruptions larger than those of historical time could generate significant amounts of volcanic ash, fallout, pyroclastic flows, and lahars that would be hazardous to life and property on all sectors of the volcano and other parts of the island, but especially in the major valleys that head on the volcano flanks. During a large eruption an ash cloud could be produced that may be hazardous to aircraft using the airfield at Cold Bay and the airspace downwind from the volcano. In the event of a large eruption, volcanic ash fallout could be relatively thick over parts of Akutan Island and volcanic bombs could strike areas more than 10 kilometers from the volcano.

  15. Hawaiian Volcano Observatory seismic data, January to December 2005

    USGS Publications Warehouse

    Nakata, Jennifer S.

    2006-01-01

    The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year. The seismic summary is offered without interpretation as a source of preliminary data. It is complete in the sense that most data for events of M-1.5 routinely gathered by the Observatory are included. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data dictated an annual publication beginning with Summary 74 for the year 1974. Summary 86 (the introduction of CUSP at HVO) includes a description of the seismic instrumentation, calibration, and processing used in recent years. Beginning with 2004, summaries will simply be identified by the year, rather than Summary number. The present summary includes background information on the seismic network and processing to allow use of the data and to provide an understanding of how they were gathered. A report by Klein and Koyanagi (1980) tabulates instrumentation, calibration, and recording history of each seismic station in the network. It is designed as a reference for users of seismograms and phase data and includes and augments the information in the station table in this summary.

  16. Hawaiian Volcano Observatory Seismic Data, January to December 2006

    USGS Publications Warehouse

    Nakata, Jennifer

    2007-01-01

    Introduction The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year. The seismic summary is offered without interpretation as a source of preliminary data. It is complete in the sense that most data for events of M>1.5 routinely gathered by the Observatory are included. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data dictated an annual publication beginning with Summary 74 for the year 1974. Summary 86 (the introduction of CUSP at HVO) includes a description of the seismic instrumentation, calibration, and processing used in recent years. Beginning with 2004, summaries are simply identified by the year, rather than Summary number. The present summary includes background information on the seismic network and processing to allow use of the data and to provide an understanding of how they were gathered. A report by Klein and Koyanagi (1980) tabulates instrumentation, calibration, and recording history of each seismic station in the network. It is designed as a reference for users of seismograms and phase data and includes and augments the information in the station table in this summary.

  17. Volcano and Earthquake Monitoring Plan for the Yellowstone Volcano Observatory, 2006-2015

    USGS Publications Warehouse

    Yellowstone Volcano Observatory

    2006-01-01

    To provide Yellowstone National Park (YNP) and its surrounding communities with a modern, comprehensive system for volcano and earthquake monitoring, the Yellowstone Volcano Observatory (YVO) has developed a monitoring plan for the period 2006-2015. Such a plan is needed so that YVO can provide timely information during seismic, volcanic, and hydrothermal crises and can anticipate hazardous events before they occur. The monitoring network will also provide high-quality data for scientific study and interpretation of one of the largest active volcanic systems in the world. Among the needs of the observatory are to upgrade its seismograph network to modern standards and to add five new seismograph stations in areas of the park that currently lack adequate station density. In cooperation with the National Science Foundation (NSF) and its Plate Boundary Observatory Program (PBO), YVO seeks to install five borehole strainmeters and two tiltmeters to measure crustal movements. The boreholes would be located in developed areas close to existing infrastructure and away from sensitive geothermal features. In conjunction with the park's geothermal monitoring program, installation of new stream gages, and gas-measuring instruments will allow YVO to compare geophysical phenomena, such as earthquakes and ground motions, to hydrothermal events, such as anomalous water and gas discharge. In addition, YVO seeks to characterize the behavior of geyser basins, both to detect any precursors to hydrothermal explosions and to monitor earthquakes related to fluid movements that are difficult to detect with the current monitoring system. Finally, a monitoring network consists not solely of instruments, but requires also a secure system for real-time transmission of data. The current telemetry system is vulnerable to failures that could jeopardize data transmission out of Yellowstone. Future advances in monitoring technologies must be accompanied by improvements in the infrastructure for data transmission. Overall, our strategy is to (1) maximize our ability to provide rapid assessments of changing conditions to ensure public safety, (2) minimize environmental and visual impact, and (3) install instrumentation in developed areas.

  18. The EarthScope Plate Boundary Observatory Akutan Alaskan Volcano Tiltmeter Installation

    NASA Astrophysics Data System (ADS)

    Pauk, B. A.; Gallaher, W.; Dittmann, T.; Smith, S.

    2007-12-01

    During August of 2007, the Plate Boundary Observatory (PBO) successfully installed four Applied Geomechanics Lily Self Leveling Borehole Tiltmeters on Akutan Volcano, in the central Aleutian islands of Alaska. All four stations were collocated with existing PBO Global Positioning Systems (GPS) stations installed on the volcano in 2005. The tiltmeters will aid researchers in detecting and measuring flank deformation associated with future magmatic intrusions of the volcano. All four of the tiltmeters were installed by PBO field crews with helicopter support provided by JL Aviation and logistical support from the Trident Seafood Corporation, the City of Akutan, and the Akutan Corporation. Lack of roads and drivable trails on the remote volcanic island required that all drilling equipment be transported to each site from the village of Akutan by slinging gear beneath the helicopter and with internal loads. Each tiltmeter hole was drilled to a depth of approximately 30 feet with a portable hydraulic/pneumatic drill rig. The hole was then cased with splined 2.75 inch PVC. The PVC casing was cemented in place with grout and the tiltmeters were installed and packed with fine grain sand to stabilize the tiltmeters inside the casing. The existing PBO NetRS GPS receivers were configured to collect the tiltmeter data through a spare receiver serial port at one sample per minute and 1 hour files. Data from the GPS receivers and tiltmeters is telemetered directly or through a repeater radio to a base station located in the village of Akutan that transmits the data using satellite based communications to connect to the internet and to the UNAVCO Facility data archive where it is made freely available to the public.

  19. Preliminary Volcano-Hazard Assessment for Gareloi Volcano, Gareloi Island, Alaska

    USGS Publications Warehouse

    Coombs, Michelle L.; McGimsey, Robert G.; Browne, Brandon L.

    2008-01-01

    Gareloi Volcano (178.794 degrees W and 51.790 degrees N) is located on Gareloi Island in the Delarof Islands group of the Aleutian Islands, about 2,000 kilometers west-southwest of Anchorage and about 150 kilometers west of Adak, the westernmost community in Alaska. This small (about 8x10 kilometer) volcano has been one of the most active in the Aleutians since its discovery by the Bering expedition in the 1740s, though because of its remote location, observations have been scant and many smaller eruptions may have gone unrecorded. Eruptions of Gareloi commonly produce ash clouds and lava flows. Scars on the flanks of the volcano and debris-avalanche deposits on the adjacent seafloor indicate that the volcano has produced large landslides in the past, possibly causing tsunamis. Such events are infrequent, occurring at most every few thousand years. The primary hazard from Gareloi is airborne clouds of ash that could affect aircraft. In this report, we summarize and describe the major volcanic hazards associated with Gareloi.

  20. Glacial cycles and the growth and destruction of Alaska volcanoes

    NASA Astrophysics Data System (ADS)

    Coombs, M. L.; Calvert, A. T.; Bacon, C. R.

    2014-12-01

    Glaciers have affected profoundly the growth, collapse, preservation, and possibly, eruptive behavior of Quaternary stratovolcanoes in Alaska. Holocene alpine glaciers have acted as effective agents of erosion on volcanoes north of ~55 °N and especially north of 60 °N. Cook Inlet volcanoes are particularly vulnerable as they sit atop rugged intrusive basement as high as 3000 m asl. Holocene glaciers have swept away or covered most of the deposits and dome lavas of frequently active Redoubt (60.5 °N); carved through the flanks of Spurr's active vent, Crater Peak (61.3 °N); and all but obscured the edifice of Hayes (61.6 °N), whose Holocene eruptive history is known almost exclusively though far-traveled tephra and flowage deposits. Relationships between Pleistocene eruptive histories, determined by high-precision Ar-Ar dating of lava flows, and marine oxygen isotope stages (MIS) 2-8 (Bassinot et al., 1994, EPSL, v. 126, p. 91­-108) vary with a volcano's latitude, size, and elevation. At Spurr, 26 ages cluster in interglacial periods. At Redoubt, 28 ages show a more continual eruptive pattern from the end of MIS 8 to the present, with a slight apparent increase in output following MIS 6, and almost no preservation before 220 ka. Veniaminof (56.2 °N) and Emmons (55.5°N), large, broad volcanoes with bases near sea level, had voluminous eruptive episodes during the profound deglaciations after MIS 8 and MIS 6. At Akutan (54.1 °N), many late Pleistocene lavas show evidence for ice contact; ongoing dating will be able to pinpoint ice thicknesses. Furthest south and west, away from thick Pleistocene ice on the Alaska Peninsula and mainland, the Tanaga volcanic cluster (51.9 °N) has a relatively continuous eruptive record for the last 200 k.y. that shows no clear-cut correlation with glacial cycles, except a possible hiatus during MIS 6. Finally, significant edifice collapse features have been temporally linked with deglaciations. A ~10-km3 debris-avalanche deposit from Spurr directly overlies bedrock, suggesting that edifice collapse closely followed MIS 2. The geologic history of Veniaminof suggests possible massive edifice collapse following MIS 6. A stack of westward-dipping lavas and breccias on the east flank of Redoubt Volcano erupted during MIS 6, and may have also failed during the major deglaciation of MIS 5.5.

  1. The story of the Hawaiian Volcano Observatory -- A remarkable first 100 years of tracking eruptions and earthquakes

    USGS Publications Warehouse

    Babb, Janet L.; Kauahikaua, James P.; Tilling, Robert I.

    2011-01-01

    The year 2012 marks the centennial of the Hawaiian Volcano Observatory (HVO). With the support and cooperation of visionaries, financiers, scientists, and other individuals and organizations, HVO has successfully achieved 100 years of continuous monitoring of Hawaiian volcanoes. As we celebrate this milestone anniversary, we express our sincere mahalo—thanks—to the people who have contributed to and participated in HVO’s mission during this past century. First and foremost, we owe a debt of gratitude to the late Thomas A. Jaggar, Jr., the geologist whose vision and efforts led to the founding of HVO. We also acknowledge the pioneering contributions of the late Frank A. Perret, who began the continuous monitoring of Kīlauea in 1911, setting the stage for Jaggar, who took over the work in 1912. Initial support for HVO was provided by the Massachusetts Institute of Technology (MIT) and the Carnegie Geophysical Laboratory, which financed the initial cache of volcano monitoring instruments and Perret’s work in 1911. The Hawaiian Volcano Research Association, a group of Honolulu businessmen organized by Lorrin A. Thurston, also provided essential funding for HVO’s daily operations starting in mid-1912 and continuing for several decades. Since HVO’s beginning, the University of Hawaiʻi (UH), called the College of Hawaii until 1920, has been an advocate of HVO’s scientific studies. We have benefited from collaborations with UH scientists at both the Hilo and Mänoa campuses and look forward to future cooperative efforts to better understand how Hawaiian volcanoes work. The U.S. Geological Survey (USGS) has operated HVO continuously since 1947. Before then, HVO was under the administration of various Federal agencies—the U.S. Weather Bureau, at the time part of the Department of Agriculture, from 1919 to 1924; the USGS, which first managed HVO from 1924 to 1935; and the National Park Service from 1935 to 1947. For 76 of its first 100 years, HVO has been part of the USGS, the Nation’s premier Earth science agency. It currently operates under the direction of the USGS Volcano Science Center, which now supports five volcano observatories covering six U.S. areas—Hawaiʻi (HVO), Alaska and the Northern Mariana Islands (Alaska Volcano Observatory), Washington and Oregon (Cascades Volcano Observatory), California (California Volcano Observatory), and the Yellowstone region (Yellowstone Volcano Observatory). Although the National Park Service (NPS) managed HVO for only 12 years, HVO has enjoyed a close working relationship with Hawaiʻi Volcanoes National Park (named Hawaii National Park until 1961) since the park’s founding in 1916. Today, as in past years, the USGS and NPS work together to ensure the safety and education of park visitors. We are grateful to all park employees, particularly Superintendent Cindy Orlando and Chief Ranger Talmadge Magno and their predecessors, for their continuing support of HVO’s mission. HVO also works closely with the Hawaiʻi County Civil Defense. During volcanic and earthquake crises, we have appreciated the support of civil defense staff, especially that of Harry Kim and Quince Mento, who administered the agency during highly stressful episodes of Kīlauea's ongoing eruption. Our work in remote areas on Hawaiʻi’s active volcanoes is possible only with the able assistance of Hawaiʻi County and private pilots who have safely flown HVO staff to eruption sites through the decades. A special mahalo goes to David Okita, who has been HVO’s principal helicopter pilot for more than two decades. Many commercial and Civil Air Patrol pilots have also assisted HVO by reporting their observations during various eruptive events. Hawaiʻi’s news media—print, television, radio, and online sources—do an excellent job of distributing volcano and earthquake information to the public. Their assistance is invaluable to HVO, especially during times of crisis. HVO’s efforts to provide timely and accurate scientific information about Hawaiian volcanoes and earthquakes succeed only because of you, our receptive and keenly aware public. By following the activity of Hawaiʻi’s active volcanoes through our daily eruption updates posted on the HVO website, viewing HVO webcam images, reading our weekly “Volcano Watch” articles, and attending our public lectures, you help us to ensure that you can live safely with Hawaiʻi’s dynamic volcanoes. To everyone who has shared in HVO’s reaching this milestone—100 years of continuous volcano monitoring—we extend our deepest gratitude. Mahalo nui loa!

  2. Evidence for dike emplacement beneath Iliamna Volcano, Alaska in 1996

    USGS Publications Warehouse

    Roman, D.C.; Power, J.A.; Moran, S.C.; Cashman, K.V.; Doukas, M.P.; Neal, C.A.; Gerlach, T.M.

    2004-01-01

    Two earthquake swarms, comprising 88 and 2833 locatable events, occurred beneath Iliamna Volcano, Alaska, in May and August of 1996. Swarm earthquakes ranged in magnitude from -0.9 to 3.3. Increases in SO2 and CO2 emissions detected during the fall of 1996 were coincident with the second swarm. No other physical changes were observed in or around the volcano during this time period. No eruption occurred, and seismicity and measured gas emissions have remained at background levels since mid-1997. Earthquake hypocenters recorded during the swarms form a cluster in a previously aseismic volume of crust located to the south of Iliamna's summit at a depth of -1 to 4 km below sea level. This cluster is elongated to the NNW-SSE, parallel to the trend of the summit and southern vents at Iliamna and to the regional axis of maximum compressive stress determined through inversion of fault-plane solutions for regional earthquakes. Fault-plane solutions calculated for 24 swarm earthquakes located at the top of the new cluster suggest a heterogeneous stress field acting during the second swarm, characterized by normal faulting and strike-slip faulting with p-axes parallel to the axis of regional maximum compressive stress. The increase in earthquake rates, the appearance of a new seismic volume, and the elevated gas emissions at Iliamna Volcano indicate that new magma intruded beneath the volcano in 1996. The elongation of the 1996-1997 earthquake cluster parallel to the direction of regional maximum compressive stress and the accelerated occurrence of both normal and strike-slip faulting in a small volume of crust at the top of the new seismic volume may be explained by the emplacement and inflation of a subvertical planar dike beneath the summit of Iliamna and its southern satellite vents. ?? 2003 Elsevier B.V. All rights reserved.

  3. Hawaiian Volcano Observatory Seismic Data, January to December 2007

    USGS Publications Warehouse

    Nakata, Jennifer S.; Okubo, Paul G.

    2008-01-01

    The U.S. Geological Survey (USGS), Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year. The seismic summary is offered without interpretation as a source of preliminary data and is complete in that most data for events of M=1.5 are included. All latitude and longitude references in this report are stated in Old Hawaiian Datum. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data necessitated an annual publication, beginning with Summary 74 for the year 1974. Beginning in 2004, summaries are simply identified by the year, rather than by summary number. Summaries originally issued as administrative reports were republished in 2007 as Open-File Reports. All the summaries since 1956 are listed at http://geopubs.wr.usgs.gov/ (last accessed September 30, 2008). In January 1986, HVO adopted CUSP (California Institute of Technology USGS Seismic Processing). Summary 86 includes a description of the seismic instrumentation, calibration, and processing used in recent years. The present summary includes background information about the seismic network to provide the end user an understanding of the processing parameters and how the data were gathered. A report by Klein and Koyanagi (1980) tabulates instrumentation, calibration, and recording history of each seismic station in the network. It is designed as a reference for users of seismograms and phase data and includes and augments the information in the station table in this summary.

  4. Renewed Seismic Unrest at Mount Spurr Volcano, Alaska in 2004: Evidence for a Magmatic Intrusion

    NASA Astrophysics Data System (ADS)

    Power, J. A.; Stihler, S. D.; Dixon, J. P.; Moran, S. C.; Caplan-Auerbach, J.; Prejean, S. G.; McGee, K.; Doukas, M. P.; Roman, D. C.

    2004-12-01

    In early July 2004 the Alaska Volcano Observatory (AVO) detected a pronounced increase in seismic activity beneath the summit of Mount Spurr volcano that continues at present. From 1 July through 31 August 2004, AVO located 1094 Volcano-Tectonic (VT) earthquakes and 177 Long-Period (LP) events within 12 km of the volcano's summit, although many events classified as VT contained mixed frequencies. The largest event has a magnitude of 1.6 and hypocentral depths generally range from 0 to 5 km below sea-level. The cumulative seismic moment for July - August 2004 is 5x10**13 Nm. Focal mechanisms of located events in July and August 2004 are dominated by normal faulting, which is consistent with what has been observed beneath the summit since 1984. This seismicity rate is the highest observed at Mount Spurr since the conclusion of the 1992 eruption sequence. Seismicity in 2004 differs markedly from that observed prior to the eruptions in 1992 in that almost all hypocenters are concentrated beneath the volcano's summit vent and not the historically active Crater Peak vent, site of eruptions in 1953 and 1992. Analysis of AVO earthquake catalogs suggests anomalous seismicity may have begun as early as 20 October 2002 with a prominent swarm of 60 VT earthquakes (Mmax = 2.4) located roughly 2 km west of the volcano's summit. Smaller increases in the shallow seismicity rates were also noted between July and November 2003 and beginning in February 2004. These events ranged in depth between 0 and 4 km below sea-level. A subtle increase of deep LP events was also detected beginning in July 2003 and peaking in June 2004, immediately prior to the onset of strong shallow seismicity. These events concentrate about 4 km to the southeast of Crater Peak, generally range in depth from 20 to 35 km and occur at a rate of 2 to 4 located events per month. Associated with the 2004 seismic activity AVO has also observed anomalous melting and disruption of the summit ice cap that began in late May or early June 2004. On 7 August 2004 an emission rate of 600 metric tons per day of CO2 was measured and H2S was also detected (more than 1 ton per day). The increase in earthquake rates, initiation of both deep and shallow LP events, the melting of the summit ice cap, and the degassing of both CO2 and H2S suggest that new magma intruded beneath the volcano possibly as early as October 2002.

  5. Hawaiian Volcano Observatory Seismic Data, January to December 2008

    USGS Publications Warehouse

    Nakata, Jennifer S.; Okubo, Paul G.

    2009-01-01

    The U.S. Geological Survey (USGS), Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year. The seismic summary is offered without interpretation as a source of preliminary data and is complete in that most data for events of M greater than 1.5 are included. All latitude and longitude references in this report are stated in Old Hawaiian Datum. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data necessitated an annual publication, beginning with Summary 74 for the year 1974. Beginning in 2004, summaries are simply identified by the year, rather than by summary number. Summaries originally issued as administrative reports were republished in 2007 as Open-File Reports. All the summaries since 1956 are listed at http://geopubs.wr.usgs.gov/ (last accessed 09/21/2009). In January 1986, HVO adopted CUSP (California Institute of Technology USGS Seismic Processing). Summary 86 includes a description of the seismic instrumentation, calibration, and processing used in recent years. The present summary includes background information about the seismic network to provide the end user an understanding of the processing parameters and how the data were gathered. A report by Klein and Koyanagi (1980) tabulates instrumentation, calibration, and recording history of each seismic station in the network. It is designed as a reference for users of seismograms and phase data and includes and augments the information in the station table in this summary. Figures 11-14 are maps showing computer-located hypocenters. The maps were generated using the Generic Mapping Tools (GMT http://gmt.soest.hawaii.edu/, last accessed 09/21/2009) in place of traditional Qplot maps.

  6. An improved proximal tephrochronology for Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Schiff, Caleb J.; Kaufman, Darrell S.; Wallace, Kristi L.; Ketterer, Michael E.

    2010-06-01

    Sediment cores from lakes in volcanically active regions can be used to reconstruct the frequency of tephra-fall events. We studied sediment cores from two lakes within 25 km of the summit of Redoubt Volcano, western Cook Inlet, to develop a robust age model for the Holocene tephrochronology, and to assess the extent to which the tephrostratigraphies were correlative between the two nearby lakes. Visually distinct tephra layers were correlated among cores from Bear and Cub lakes, located within 17 km of each other, to construct a composite age model, which incorporates two Pu-activity profiles and 27 radiocarbon ages, and extends the record back to 11,540 cal a BP. The age model was used to interpolate the ages and quantify the uncertainties of ages for all tephras at least 1 mm thick. Between - 55 and 3850 a BP, 31 tephras were deposited in Bear Lake and 41 tephras in Cub Lake. Bear Lake contains an additional 38 tephras deposited between 11,540 and 3850 a BP. During the period of overlap, (- 55 to 3850 a BP), 24 tephras are of significantly different ages, including nine from Bear Lake and 17 from Cub Lake. The presence of these unique tephras indicates that ejecta plumes erupted from Redoubt Volcano can be highly directional, and that sediment cores from more than one lake are needed for a comprehensive reconstruction of tephra-fall events. Unlike distal lakes in south Alaska, where geomorphic and limnological factors dominate the quality of the tephrostratigraphic record, the variability in tephra-fall trajectory near a Redoubt Volcano appears to be a major control on the number of tephras contained in the sediment of proximal lakes.

  7. Landforms Produced by Permafrost-Volcano Interactions, Arctic Alaska

    NASA Astrophysics Data System (ADS)

    Beget, J.; Kargel, J.; Wessels, R.

    2005-12-01

    Three different types of distinctive landforms are recognized at sites in Arctic Alaska where volcanic eruptions occurred through permafrost. On the Seward Peninsula at ca. 66° N, a series of giant explosion craters known as the Espenberg Maars are as much as 8 km in diameter. These craters were produced by numerous explosions caused by cryo-magmatic interactions. The giant maars formed during eruptions at 21kyr, 62 ± 10 kyr, and 160 ± 8 kyr., and so are correlative with times of extremely cold climate and thick ground ice during marine isotope stages 2, 4, and 6. At Imuruk Lake at ca. 65° N the Lost Jim lava flow was erupted only a few thousand years ago. The basaltic lava flow advanced over permafrost, and are bounded by unusually steep flow fronts and levees as much as 20 m high, covered with lava flow surfaces sloping as much as 60°. These `super-inflated' flow margins terminate in zones of complex thermokarst collapse features recording melting of ground ice under the lava. We speculate that as the lava flow advanced it melted ground ice and produced steam that quenched the lava and produced extremely steep and inflated flow margins. At the Ingakslugwat Hills at ca. 61.5° N., unusual composite volcanoes as much as 7 km long and 400 m high are made largely of pyroclastic ejecta. These features are significantly higher than the regional water table, and yet are capped with maars and numerous intersecting arms of explosion craters of various. We call these distinctive landforms Ingakslugwat volcanoes. We suggest that since the water table is hundreds of meters lower, the water source for continued explosive volcanism in Ingakslugwat Volcanoes is the melting of ground ice in permafrost. We hypothesize the permafrost table rises in the new ejecta following each successive eruption, resulting in multiple cycles of cryo-magmatic explosive volcanism and the creation of thick complexes of volcaniclastic debris.

  8. Intermediate-Term Declines in Seismicity at Two Volcanoes in Alaska Following the Mw7.9 Denali Fault Earthquake

    NASA Astrophysics Data System (ADS)

    McNutt, S. R.; Sanchez, J. J.; Moran, S. C.; Power, J. A.

    2002-12-01

    The Mw7.9 Denali Fault earthquake provided an opportunity to look for intermediate-term (days to weeks) responses of Alaskan volcanoes to shaking from a large regional earthquake. The Alaska Volcano Observatory monitors 24 volcanoes with seismic networks. We examined one station for each volcano, generally the closest (typically 5 km from the vent) unless noise, site response, or other factors made the data unusable. Data were digitally bandpass filtered between 0.8 and 5 Hz to reduce noise from microseisms and wind. Data for the period three days before to three days after the Mw7.9 earthquake were then plotted at a standard scale used for AVO routine monitoring. Shishaldin volcano, which has a background rate of several hundred seismic events per day on station SSLS, showed no change from before to after the earthquake. Veniaminof volcano, which has had recent mild eruptions and a rate of several dozen seismic events per day on station VNNF, suffered a drop in seismicity at the time of the earthquake by a factor of 2.5; this lasted for 15 days. We tested this result using a different station, VNSS, and a different method of counting (non-filtered data on helicorder records) and found the same result. We infer that Veniaminof's activity was modified by the Mw7.9 earthquake. Wrangell, the closest volcano, had a background rate of about 10 events per day. Data from station WANC could not be measured for 8 days after the Mw7.9 earthquake because the large number of aftershocks precluded identification of local seismicity. For the following eight days, however, its seismicity rate was 30 percent lower than before. While subtle, we infer that this may be related to the earthquake. It is known that Wrangell increased its heat output after the Mw9.2 Alaska earthquake of 1964 and again after the Ms7.1 St. Elias earthquake of 1979. The other 21 volcanoes showed no changes in seismicity from 3 days before to 3 days after the Mw7.9 event. We conclude that intermediate-term seismicity decreases occurred at two Alaskan volcanoes, in strong contrast to cases of triggered seismicity increases observed at volcanic systems such as Katmai, Mount Rainier, Mammoth Mountain, and Yellowstone. This suggests that fundamentally different mechanisms may be acting to modify or trigger seismicity at volcanoes.

  9. Airborne Gas Surveillance of Volcanoes in Western USA and Alaska

    NASA Astrophysics Data System (ADS)

    Gerlach, T. M.; McGee, K. A.; Doukas, M. P.

    2002-05-01

    Volcanoes of the western USA and Alaska pose challenges to gas surveillance of volcano unrest. Locations are remote, and ground access is generally difficult. Wet climates and melt from glaciers and thick winter snowpack foster hydrothermal and ground waters that can scrub acid gases (SO2, HCl, HF) before they reach the surface, thereby masking their degassing from shallow vapor-saturated subvolcanic magma. These gases may not exhibit significant increases in emission rates until dry pathways or magma itself reaches the surface. Background or low emissions of the acid gases may thus give a false sense of security. CO2 is more likely to give early indication of subvolcanic magma degassing. It is the second most abundant magmatic volatile; it is among the least soluble magmatic volatiles; and it is far less susceptible to scrubbing than SO2, HCl, or HF. Rising H2S emissions are also a plausible early warning, since unlike SO2, HCl and HF, H2S is strongly volatilized from boiling water. Unfortunately, remote sensing of early increases in volcanic CO2 and H2S emissions is usually problematic, owing to high atmospheric CO2 levels, water vapor interference, and poor H2S infrared absorbance. We have therefore developed an aircraft-mounted system that directly measures these gases by extraction sampling of plumes. The system includes an infrared spectrometer for CO2 and an electrochemical sensor for H2S, in addition to a COSPEC and high-precision barometer, temperature probe, and GPS receiver. Measurements are made at different elevations along traverses orthogonal to plume direction or along orbits around a volcano if plume is not visible. Data for all gases are recorded in a data logger at 1-s intervals and tagged with clock time, latitude, longitude, altitude, temperature, and pressure. In-flight wind data are also acquired. Plume cross-sections are constructed with mapping software and used to calculate emission rates. Several campaigns to date show that emission rates of <200 metric tons/day (t/d) CO2 and <10 t/d H2S are easily detected and suggest that scrubbing is widespread in Cascade and Aleutian arc volcanoes.

  10. NOAA Atmospheric Baseline Observatories in the Arctic: Alaska & Greenland

    NASA Astrophysics Data System (ADS)

    Vasel, B. A.; Butler, J. H.; Schnell, R. C.; Crain, R.; Haggerty, P.; Greenland, S.

    2013-12-01

    The National Oceanic and Atmospheric Administration (NOAA) operates two year-round, long-term climate research facilities, known as Atmospheric Baseline Observatories (ABOs), in the Arctic Region. The Arctic ABOs are part of a core network to support the NOAA Global Monitoring Division's mission to acquire, evaluate, and make available accurate, long-term records of atmospheric gases, aerosol particles, and solar radiation in a manner that allows the causes of change to be understood. The observatory at Barrow, Alaska (BRW) was established in 1973 and is now host to over 200 daily measurements. Located a few kilometers to the east of the village of Barrow at 71.3° N it is also the northernmost point in the United States. Measurement records from Barrow are critical to our understanding of the Polar Regions including exchange among tundra, atmosphere, and ocean. Multiple data sets are available for carbon cycle gases, halogenated gases, solar radiation, aerosol properties, ozone, meteorology, and numerous others. The surface, in situ carbon dioxide record alone consists of over 339,000 measurements since the system was installed in July 1973. The observatory at Summit, Greenland (SUM) has been a partnership with the National Science Foundation (NSF) Division of Polar Programs since 2004, similar to that for South Pole. Observatory data records began in 1997 from this facility located at the top of the Greenland ice sheet at 72.58° N. Summit is unique as the only high-altitude (3200m), mid-troposphere, inland, Arctic observatory, largely free from outside local influences such as thawing tundra or warming surface waters. The measurement records from Summit help us understand long-range transport across the Arctic region, as well as interactions between air and snow. Near-real-time data are available for carbon cycle gases, halogenated gases, solar radiation, aerosol properties, meteorology, ozone, and numerous others. This poster will highlight the two facilities, key partners at each, available data sets, and cooperative research opportunities.

  11. Observing active deformation of volcanoes in North America: Geodetic data from the Plate Boundary Observatory and associated networks

    NASA Astrophysics Data System (ADS)

    Puskas, C. M.; Phillips, D. A.; Mattioli, G. S.; Meertens, C. M.; Hodgkinson, K. M.; Crosby, C. J.; Enders, M.; Feaux, K.; Mencin, D.; Baker, S.; Lisowski, M.; Smith, R. B.

    2013-12-01

    The EarthScope Plate Boundary Observatory (PBO), operated by UNAVCO, records deformation of the geologically diverse North America western plate boundary, with subnetworks of instruments concentrated at selected active and potentially active volcanoes. These sensors record deformation and earthquakes and allow monitoring agencies and researchers to analyze changes in ground motion and seismicity. The intraplate volcanoes at Yellowstone and Long Valley are characterized by uplift/subsidence cycles, high seismicity, and hydrothermal activity but there have been no historic eruptions at either volcano. PBO maintains dense GPS networks of 20-25 stations at each of these volcanoes, with an additional 5 boreholes at Yellowstone containing tensor strainmeters, short-period seismometers, and borehole tiltmeters. Subduction zone volcanoes in the Aleutian Arc have had multiple historic eruptions, and PBO maintains equipment at Augustine (8 GPS), Akutan (8 GPS, 4 tiltmeters), and Unimak Island (14 GPS, 8 tiltmeters). The Unimak stations are at the active Westdahl and Shishaldin edifices and the nearby, inactive Isanotski volcano. In the Cascade Arc, PBO maintains networks at Mount St. Helens (15 GPS, 4 borehole strainmeters and seismometers, 8 borehole tiltmeters), Shasta (7 GPS, 1 borehole strainmeter and seismometer), and Lassen Peak (8 GPS). Data from many of these stations in the Pacific Northwest and California are also provided as realtime streams of raw and processed data. Real-time GPS data, along with high-rate GPS data, will be an important new resource for detecting and studying future rapid volcanic deformation events and earthquakes. UNAVCO works closely with the USGS Volcano Hazards Program, archiving data from USGS GPS stations in Alaska, Cascadia, and Long Valley. The PBO and USGS networks combined provide more comprehensive coverage than PBO alone, particularly of the Cascade Arc, where the USGS maintains a multiple instruments near each volcano. Ground-based instruments are supplemented by remote sensing data sets. UNAVCO supports the acquisition of InSAR and LiDAR imaging data, with archiving and distribution of these data provided by UNAVCO and partner institutions. We provide descriptions and access information for geodetic data from the PBO volcano subnetworks and their applications to monitoring for scientific and public safety objectives. We also present notable examples of activity recorded by these instruments, including the 2004-2010 accelerated uplift episode at the Yellowstone caldera and the 2006 Augustine eruption.

  12. Determination and uncertainty of moment tensors for microearthquakes at Okmok Volcano, Alaska

    USGS Publications Warehouse

    Pesicek, J.D.; Sileny, J.; Prejean, S.G.; Thurber, C.H.

    2012-01-01

    Efforts to determine general moment tensors (MTs) for microearthquakes in volcanic areas are often hampered by small seismic networks, which can lead to poorly constrained hypocentres and inadequate modelling of seismic velocity heterogeneity. In addition, noisy seismic signals can make it difficult to identify phase arrivals correctly for small magnitude events. However, small volcanic earthquakes can have source mechanisms that deviate from brittle double-couple shear failure due to magmatic and/or hydrothermal processes. Thus, determining reliable MTs in such conditions is a challenging but potentially rewarding pursuit. We pursued such a goal at Okmok Volcano, Alaska, which erupted recently in 1997 and in 2008. The Alaska Volcano Observatory operates a seismic network of 12 stations at Okmok and routinely catalogues recorded seismicity. Using these data, we have determined general MTs for seven microearthquakes recorded between 2004 and 2007 by inverting peak amplitude measurements of P and S phases. We computed Green's functions using precisely relocated hypocentres and a 3-D velocity model. We thoroughly assessed the quality of the solutions by computing formal uncertainty estimates, conducting a variety of synthetic and sensitivity tests, and by comparing the MTs to solutions obtained using alternative methods. The results show that MTs are sensitive to station distribution and errors in the data, velocity model and hypocentral parameters. Although each of the seven MTs contains a significant non-shear component, we judge several of the solutions to be unreliable. However, several reliable MTs are obtained for a group of previously identified repeating events, and are interpreted as compensated linear-vector dipole events.

  13. Constructing a reference tephrochronology for Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Wallace, K.; Coombs, M. L.

    2013-12-01

    Augustine Volcano is the most historically active volcano in Alaska's populous Cook Inlet region. Past on-island work on pre-historic tephra deposits mainly focused on using tephra layers as markers to help distinguish among prevalent debris-avalanche deposits on the island (Waitt and Beget, 2009, USGS Prof Paper 1762), or as source material for petrogenetic studies. No comprehensive reference study of tephra fall from Augustine Volcano previously existed. Numerous workers have identified Holocene-age tephra layers in the region surrounding Augustine Island, but without well-characterized reference deposits, correlation back to the source volcano is difficult. The purpose of this detailed tephra study is to provide a record of eruption frequency and magnitude, as well as to elucidate physical and chemical characteristics for use as reference standards for comparison with regionally distributed Augustine tephra layers. Whole rock major- and trace-element geochemistry, deposit componentry, and field context are used to correlate tephra units on the island where deposits are coarse grained. Major-element glass geochemistry was collected for use in correlating to unknown regional tephra. Due to the small size of the volcanic island (9 by 11 km in diameter) and frequent eruptive activity, on-island exposures of tephra deposits older than a couple thousand years are sparse, and the lettered Tephras B, M, C, H, I, and G of Waitt and Beget (2009) range in age from 370-2200 yrs B.P. There are, however, a few exposures on the south side of the volcano, within about 2 km of the vent, where stratigraphic sections that extend back to the late Pleistocene glaciation include coarse pumice-fall deposits. We have linked the letter-named tephras from the coast to these higher exposures on the south side using physical and chemical characteristics of the deposits. In addition, these exposures preserve at least 5 older major post-glacial eruptions of Augustine. These ultra-proximal sites, along with an off-island section 20 km to the west, provide the first continuous tephrochronology for Augustine that extends from the earliest to latest Holocene. Because examined pumice-fall exposures are limited to a narrow azimuth on the south side of the volcano, the on-island record is likely an incomplete catalog of major eruptions. It is possible however, that the coarse-grained near vent exposures (within 2 km) represent large eruptions that blanketed the entire island in tephra and are representative of the entire Holocene record. The major Holocene tephra units exposed on-island are composed of coarse-grained (cm-scale) pumice ranging in color from white to cream (variably oxidized), and light to medium gray as well as banded varieties. Accidental lithic assembles are highly variable and often unique for individual eruptions. Pumices range from 60-66 wt % SiO2 in whole-rock composition and are distinguishable using trace and minor element abundances and field context. Glass geochemistry is often distinguishable between tephras, but more overlap exists among deposits and presents challenges for correlating to regional tephras.

  14. Constructing a reference tephrochronology for Augustine Volcano, Alaska

    USGS Publications Warehouse

    Wallace, Kristi; Coombs, Michelle L.

    2013-01-01

    Augustine Volcano is the most historically active volcano in Alaska's populous Cook Inlet region. Past on-island work on pre-historic tephra deposits mainly focused on using tephra layers as markers to help distinguish among prevalent debris-avalanche deposits on the island (Waitt and Beget, 2009, USGS Prof Paper 1762), or as source material for petrogenetic studies. No comprehensive reference study of tephra fall from Augustine Volcano previously existed. Numerous workers have identified Holocene-age tephra layers in the region surrounding Augustine Island, but without well-characterized reference deposits, correlation back to the source volcano is difficult. The purpose of this detailed tephra study is to provide a record of eruption frequency and magnitude, as well as to elucidate physical and chemical characteristics for use as reference standards for comparison with regionally distributed Augustine tephra layers. Whole rock major- and trace-element geochemistry, deposit componentry, and field context are used to correlate tephra units on the island where deposits are coarse grained. Major-element glass geochemistry was collected for use in correlating to unknown regional tephra. Due to the small size of the volcanic island (9 by 11 km in diameter) and frequent eruptive activity, on-island exposures of tephra deposits older than a couple thousand years are sparse, and the lettered Tephras B, M, C, H, I, and G of Waitt and Beget (2009) range in age from 370-2200 yrs B.P. There are, however, a few exposures on the south side of the volcano, within about 2 km of the vent, where stratigraphic sections that extend back to the late Pleistocene glaciation include coarse pumice-fall deposits. We have linked the letter-named tephras from the coast to these higher exposures on the south side using physical and chemical characteristics of the deposits. In addition, these exposures preserve at least 5 older major post-glacial eruptions of Augustine. These ultra-proximal sites, along with an off-island section 20 km to the west, provide the first continuous tephrochronology for Augustine that extends from the earliest to latest Holocene. Because examined pumice-fall exposures are limited to a narrow azimuth on the south side of the volcano, the on-island record is likely an incomplete catalog of major eruptions. It is possible however, that the coarse-grained near vent exposures (within 2 km) represent large eruptions that blanketed the entire island in tephra and are representative of the entire Holocene record. The major Holocene tephra units exposed on-island are composed of coarse-grained (cm-scale) pumice ranging in color from white to cream (variably oxidized), and light to medium gray as well as banded varieties. Accidental lithic assembles are highly variable and often unique for individual eruptions. Pumices range from 60-66 wt % SiO2 in whole-rock composition and are distinguishable using trace and minor element abundances and field context. Glass geochemistry is often distinguishable between tephras, but more overlap exists among deposits and presents challenges for correlating to regional tephras.

  15. Scientists probe Earth’s secrets at the Hawaiian Volcano Observatory

    USGS Publications Warehouse

    Unger, J.D.

    1974-01-01

    The Hawaiian Volcano Observatory (HVO) sits on the edge of Kilauea Caldera at the summit of Kilauea Volcao, one of the five volcanoes on the island of Hawaii, the largest island in the Hawaiian Islands chain. Of the five, only Kilauea and Mauna Loa have been active in the past 100 years. Before its last eruption in June 1950, Mauna Loa had erupted more frequently and copiously than Kilauea, but since then only Kilauea has been active. 

  16. Double Difference Earthquake Relocation and Tomography at Mount Spurr Volcano, Alaska, 1991 to 2004

    NASA Astrophysics Data System (ADS)

    Brown, J.; Prejean, S.; Zhang, H.; Power, J.

    2004-12-01

    Mount Spurr, one of the northernmost active volcanoes monitored by the Alaska Volcano Observatory, is located approximately 120 km west of Anchorage in the Cook Inlet region. Mount Spurr erupted three times in 1992. In the subsequent decade the volcano was relatively quiet. However, seismicity rates began increasing again in early 2004, indicating that the volcano is entering a new stage of unrest. In order to gain a better understanding of the temporal and spatial distribution of seismicity at Mount Spurr, we relocated earthquakes from 1991 through 2004 using the double difference relocation code hypoDD (Waldhauser and Ellsworth, 2000). We also solved for the P-wave velocity structure of Spurr with the same dataset using the adaptive grid double difference tomography algorithm, tomoADD (Zhang and Thurber, 2004), in order to image the internal structure of the volcano and evaluate the applicability of this technique in a volcanic setting. Even though the seismic array at Mount Spurr is relatively sparse (10 short period stations) earthquake relocations result in significantly more precise hypocenters. The hypocenters from the 1992 eruptive sequence define a conduit-like structure extending from the Crater Peak vent (~2 km above sea level) to over 20 km depth, dipping steeply to the southeast. Earthquakes under the summit of Spurr (~3 km above sea level), whose vent has been quiet historically, are more scattered epicentrally and generally restricted to depths of < 5 km below sea level. Using tomoADD we imaged a low velocity body beneath the Crater Peak vent from depths of roughly 1 km above sea level to up to 10 km below sea level. This low velocity body is co-located with the steeply dipping 1992 seismicity lineation defined by relocations and likely reflects the magmatic conduit and/or the presence of a hydrothermal system southeast of Crater Peak. The spatial distribution of low velocity bodies determined using tomoADD is consistent with that determined previously by more traditional finite difference tomography techniques (Power et al., 1994). Both hypoDD and tomoADD appear to be useful methods even in relatively sparsely instrumented volcanic settings.

  17. Hawaiian Volcano Observatory seismic data, January to March 2009

    USGS Publications Warehouse

    Nakata, Jennifer S.; Okubo, Paul G.

    2010-01-01

    This U.S. Geological Survey (USGS), Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during January-March 2009. The seismic summary offers earthquake hypocenters without interpretation as a source of preliminary data and is complete in that most data for events of M=1.5 are included. All latitude and longitude references in this report are stated in Old Hawaiian Datum. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data necessitated an annual publication, beginning with Summary 74 for the year 1974. Since 2004, summaries have been identified simply by year, rather than by summary number. Summaries originally issued as administrative reports were republished in 2007 as Open-File Reports. All the summaries since 1956 are available at http://pubs.usgs.gov/of/2007/1316-1345/ (last accessed 02/24/2010). In January 1986, HVO adopted CUSP (California Institute of Technology USGS Seismic Processing). Summary 86, available at http://pubs.er.usgs.gov/usgspubs/ofr/ofr92301 (last accessed 02/24/2010), includes a description of the seismic instrumentation, calibration, and processing used in recent years. The present summary includes background information about the seismic network to provide the end user with an understanding of the processing parameters and how the data were gathered. Earthworm software, documentation available at http://folkworm.ceri.memphis.edu/ew-doc/ (last accessed 02/24/2010), was first installed at HVO in 1999 as part of an upgrade to tsunami warning capabilities in the Pacific region. This improved and expanded data exchange with the Pacific Tsunami Warning Center in Ewa Beach, Oahu, that included not only seismic waveforms, but also parametric earthquake data. Although Earthworm does included modules for earthquake triggering and earthquake location, this software was never used to generate catalog hypocenter locations at HVO. During 2009, HVO migrated from CUSP to seismic processing software developed by the California Integrated Seismic Network or CISN. This software is now referred to as AQMS, for Advanced National Seismic System Quake Management System. Summary data for this year will be presented in two reports; the first report includes earthquakes processed on the CUSP platform for January-March; earthquakes for the last three quarters, processed on the AQMS platform, will be published in a separate summary with a description of AQMS production parameters. A report by Klein and Koyanagi (USGS Open-File Report 80-302, 1980) tabulates instrumentation, calibration, and recording history of each seismic station in the network. It is designed as a reference for users of seismograms and phase data and includes and augments the information in the station table in this summary. Figures 11-14 are maps showing computer-located hypocenters. The maps were generated using the Generic Mapping Tools (GMT), found at http://gmt.soest.hawaii.edu/ (last accessed 01/22/2010), in place of traditional QPLOT maps.

  18. Initiative for the creation of an integrated infrastructure of European Volcano Observatories

    NASA Astrophysics Data System (ADS)

    Puglisi, G.; Bachelery, P.; Ferreira, T. J. L.; Vogfjörd, K. S.

    2012-04-01

    Active volcanic areas in Europe constitute a direct threat to millions of European citizens. The recent Eyjafjallajökull eruption also demonstrated that indirect effects of volcanic activity can present a threat to the economy and the lives of hundreds of million of people living in the whole continental area even in the case of activity of volcanoes with sporadic eruptions. Furthermore, due to the wide political distribution of the European territories, major activities of "European" volcanoes may have a worldwide impact (e.g. on the North Atlantic Ocean, West Indies included, and the Indian Ocean). Our ability to understand volcanic unrest and forecast eruptions depends on the capability of both the monitoring systems to effectively detect the signals generated by the magma rising and on the scientific knowledge necessary to unambiguously interpret these signals. Monitoring of volcanoes is the main focus of volcano observatories, which are Research Infrastructures in the ESFRI vision, because they represent the basic resource for researches in volcanology. In addition, their facilities are needed for the design, implementation and testing of new monitoring techniques. Volcano observatories produce a large amount of monitoring data and represent extraordinary and multidisciplinary laboratories for carrying out innovative joint research. The current distribution of volcano observatories in Europe and their technological state of the art is heterogeneous because of different types of volcanoes, different social requirements, operational structures and scientific background in the different volcanic areas, so that, in some active volcanic areas, observatories are lacking or poorly instrumented. Moreover, as the recent crisis of the ash in the skies over Europe confirms, the assessment of the volcanic hazard cannot be limited to the immediate areas surrounding active volcanoes. The whole European Community would therefore benefit from the creation of a network of volcano observatories, which would enable strengthening and sharing the technological and scientific level of current infrastructures. Such a network could help to achieve the minimum goal of deploying an observatory in each active volcanic area, and lay the foundation for an efficient and effective volcanic monitoring system at the European level.

  19. Radar observations of the 2009 eruption of Redoubt Volcano, Alaska: Initial deployment of a transportable Doppler radar system for volcano-monitoring

    NASA Astrophysics Data System (ADS)

    Hoblitt, R. P.; Schneider, D. J.

    2009-12-01

    The rapid detection of explosive volcanic eruptions and accurate determination of eruption-column altitude and ash-cloud movement are critical factors in the mitigation of volcanic risks to aviation and in the forecasting of ash fall on nearby communities. The U.S. Geological Survey (USGS) deployed a transportable Doppler radar during the precursory stage of the 2009 eruption of Redoubt Volcano, Alaska, and it provided valuable information during subsequent explosive events. We describe the capabilities of this new monitoring tool and present data that it captured during the Redoubt eruption. The volcano-monitoring Doppler radar operates in the C-band (5.36 cm) and has a 2.4-m parabolic antenna with a beam width of 1.6 degrees, a transmitter power of 330 watts, and a maximum effective range of 240 km. The entire disassembled system, including a radome, fits inside a 6-m-long steel shipping container that has been modified to serve as base for the antenna/radome, and as a field station for observers and other monitoring equipment. The radar was installed at the Kenai Municipal Airport, 82 km east of Redoubt and about 100 km southwest of Anchorage. In addition to an unobstructed view of the volcano, this secure site offered the support of the airport staff and the City of Kenai. A further advantage was the proximity of a NEXRAD Doppler radar operated by the Federal Aviation Administration. This permitted comparisons with an established weather-monitoring radar system. The new radar system first became functional on March 20, roughly a day before the first of nineteen explosive ash-producing events of Redoubt between March 21 and April 4. Despite inevitable start-up problems, nearly all of the events were observed by the radar, which was remotely operated from the Alaska Volcano Observatory office in Anchorage. The USGS and NEXRAD radars both detected the eruption columns and tracked the directions of drifting ash clouds. The USGS radar scanned a 45-degree sector centered on the volcano while NEXRAD scanned a full 360 degrees. The sector strategy scanned the volcano more frequently than the 360-degree strategy. Consequently, the USGS system detected event onset within less than a minute, while the NEXRAD required about 4 minutes. The observed column heights were as high as 20 km above sea level and compared favorably to those from NEXRAD. NEXRAD tracked ash clouds to greater distances than the USGS system. This experience shows that Doppler radar is a valuable complement to traditional seismic and satellite monitoring of explosive eruptions.

  20. A 500-year-long record of tephra falls from Redoubt Volcano and other volcanoes in upper Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Begét, James E.; Stihler, Scott D.; Stone, David B.

    1994-08-01

    Volcanic ash layers preserved in glacial-lacustrine sediments at Skilak Lake on the Kenai Peninsula of southcentral Alaska constitute a record of eruptions at Redoubt Volcano and other Alaskan volcanoes which affected the upper Cook Inlet area during the last 500 years. High-resolution magnetic susceptibility profiling delineates similar sequences of tephra layers in several 1-m-long lake sediment cores. Electron microprobe analyses of glass shards from the tephras indicate correlation of some ash layers with known reference tephras from the source volcanoes, while other ash layers record previously unknown prehistoric eruptions. Skilak Lake cores contain ash from the historic 1912 Katmai eruption, the 1902 Redoubt eruption, and the 1883 Mount St. Augustine eruption as well as prehistoric ash layers erupted from Crater Peak at Mt. Spurr ca. 250-350 years ago, from Redoubt Volcano at ca. 300-400 years ago and again at ca. 350-450 years ago, and a 500-year-old ash from Mount St. Augustine. Still older tephras from Redoubt Volcano and Crater Peak at Mt. Spurr are found lower in the cores. The cores indicate that volcanoes in the Cook Inlet area have erupted every 10-35 years during the 20th century, and ash falls have occurred at Skilak Lake at least once every 50-100 years for the last 500 years, with Redoubt, Spurr, and Augustine Volcanoes being the most important sources of tephra.

  1. Sustained long-period seismicity at Shishaldin Volcano, Alaska

    USGS Publications Warehouse

    Petersen, T.; Caplan-Auerbach, J.; McNutt, S.R.

    2006-01-01

    From September 1999 through April 2004, Shishaldin Volcano, Aleutian Islands, Alaska, exhibited a continuous and extremely high level of background seismicity. This activity consisted of many hundreds to thousands of long-period (LP; 1-2 Hz) earthquakes per day, recorded by a 6-station monitoring network around Shishaldin. The LP events originate beneath the summit at shallow depths (0-3 km). Volcano tectonic events and tremor have rarely been observed in the summit region. Such a high rate of LP events with no eruption suggests that a steady state process has been occurring ever since Shishaldin last erupted in April-May 1999. Following the eruption, the only other signs of volcanic unrest have been occasional weak thermal anomalies and an omnipresent puffing volcanic plume. The LP waveforms are nearly identical for time spans of days to months, but vary over longer time scales. The observations imply that the spatially close source processes are repeating, stable and non-destructive. Event sizes vary, but the rate of occurrence remains roughly constant. The events range from magnitude ???0.1 to 1.8, with most events having magnitudes <1.0. The observations suggest that the conduit system is open and capable of releasing a large amount of energy, approximately equivalent to at least one magnitude 1.8-2.6 earthquake per day. The rate of observed puffs (1 per minute) in the steam plume is similar to the typical seismic rates, suggesting that the LP events are directly related to degassing processes. However, the source mechanism, capable of producing one LP event about every 0.5-5 min, is still poorly understood. Shishaldin's seismicity is unusual in its sustained high rate of LP events without accompanying eruptive activity. Every indication is that the high rate of seismicity will continue without reflecting a hazardous state. Sealing of the conduit and/or change in gas flux, however, would be expected to change Shishaldin's behavior. ?? 2005 Elsevier B.V. All rights reserved.

  2. An overview of the 2009 eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Bull, Katharine F.; Buurman, Helena

    2013-06-01

    In March 2009, Redoubt Volcano, Alaska erupted for the first time since 1990. Explosions ejected plumes that disrupted international and domestic airspace, sent lahars more than 35 km down the Drift River to the coast, and resulted in tephra fall on communities over 100 km away. Geodetic data suggest that magma began to ascend slowly from deep in the crust and reached mid- to shallow-crustal levels as early as May, 2008. Heat flux at the volcano during the precursory phase melted ~ 4% of the Drift glacier atop Redoubt's summit. Petrologic data indicate the deeply sourced magma, low-silica andesite, temporarily arrested at 9-11 km and/or at 4-6 km depth, where it encountered and mixed with segregated stored high-silica andesite bodies. The two magma compositions mixed to form intermediate-silica andesite, and all three magma types erupted during the earliest 2009 events. Only intermediate- and high-silica andesites were produced throughout the explosive and effusive phases of the eruption. The explosive phase began with a phreatic explosion followed by a seismic swarm, which signaled the start of lava effusion on March 22, shortly prior to the first magmatic explosion early on March 23, 2009 (UTC). More than 19 explosions (or Events) were produced over 13 days from a single vent immediately south of the 1989-90 lava domes. During that period multiple small pyroclastic density currents flowed primarily to the north and into glacial ravines, three major lahars flooded the Drift River Terminal over 35 km down-river on the coast, tephra fall deposited on all aspects of the edifice and on several communities north and east of the volcano, and at least two, and possibly three lava domes were emplaced. Lightning accompanied almost all the explosions. A shift in the eruptive character took place following Event 9 on March 27 in terms of infrasound signal onsets, the character of repeating earthquakes, and the nature of tephra ejecta. More than nine additional explosions occurred in the next two days, followed by a hiatus in explosive activity between March 29 and April 4. During this hiatus effusion of a lava dome occurred, whose growth slowed on or around April 2. The final explosion pulverized the very poorly vesicular dome on April 4, and was immediately followed by the extrusion of the final dome that ceased growing by July 1, 2009, and reached 72 M m3 in bulk volume. The dome remains as of this writing. Effusion of the final dome in the first month produced blocky intermediate- to high-silica andesite lava, which then expanded by means of lava injection beneath a fracturing and annealing, cooling surface crust. In the first week of May, a seismic swarm accompanied extrusion of an intermediate- to high-silica andesite from the apex of the dome that was highly vesicular and characterized by lower P2O5 content. The dome remained stable throughout its growth period likely due to combined factors that include an emptied conduit system, steady degassing through coalesced vesicles in the effusing lava, and a large crater-pit created by the previous explosions. We estimate the total volume of erupted material from the 2009 eruption to be between ~ 80 M and 120 M m3 dense-rock equivalent (DRE). The aim of this report is to synthesize the results from various datasets gathered both during the eruption and retrospectively, and which are represented by the papers in this publication. We therefore provide an overall view of the 2009 eruption and an introduction to this special issue publication.

  3. Numerical simulation of tsunami generation by pryoclastic flow at Aniakchak Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, C.F.; Watts, P.

    2003-01-01

    Pyroclastic flows entering the sea are plausible mechanisms for tsunami generation at volcanic island arcs worldwide. We evaluate tsunami generation by pyroclastic flow using an example from Aniakchak volcano in Alaska where evidence for tsunami inundation coincident with a major, caldera-forming eruption of the volcano ca. 3.5 ka has been described. Using a numerical model, we simulate the tsunami and compare the results to field estimates of tsunami run up.

  4. Seismic instrumentation plan for the Hawaiian Volcano Observatory

    USGS Publications Warehouse

    Thelen, Weston A.

    2014-01-01

    The installation of new seismic stations is only the first part of building a volcanic early warning capability for seismicity in the State of Hawaii. Additional personnel will likely be required to study the volcanic processes at work under each volcano, analyze the current seismic activity at a level sufficient for early warning, build new tools for monitoring, maintain seismic computing resources, and maintain the new seismic stations.

  5. The 2008 Eruption of Kasatochi Volcano, Central Aleutian Islands, Alaska: Reconnaissance Observations and Preliminary Physical Volcanology

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Schneider, D. J.; Prejean, S. G.

    2008-12-01

    The August 7, 2008 eruption of Kasatochi volcano was the first documented historical eruption of this small (3 x 3 km) island volcano with a 1 km2 lake filled crater in the central Aleutian Islands of Alaska. Reports of previous Kasatochi eruptions are unconfirmed and lacking in detail and little is known about the eruptive history. Three explosively-generated ash plumes reaching altitudes of 15 to 20 km were observed in satellite data and were preceded by some of the most intense seismicity yet recorded by the Alaska Volcano Observatory (AVO) seismic network. Eruptive products on Kasatochi Island observed on August 22 and 23 consist of pumice-bearing, lithic-rich pyroclastic-flow deposits overlain by a 1-2 m thick sequence of fine- grained pyroclastic-surge, and -fall deposits all exposed at the coastline. These deposits completely blanket Kasatochi Island to a depth of many meters. Pyroclastic flows entered the sea and extended the coastline 300-400 m beyond prominent wave cut cliffs and sea stacks. Tide gauge data from Adak Island, 80 km to the west, indicate a small tsunami with maximum water amplitude of 20 cm, was initiated during the eruption. Kasatochi volcano lacks a real-time seismic monitoring network. Seismic activity was detected by AVO instruments on Great Sitkin Island 40 km to the west, and thus the timing of eruptive events is approximate. The eruption began explosively at 2201 UTC on August 7, and was followed by at least two additional strong eruptive bursts at 0150 UTC and 0435 UTC, August 8. Satellite data show a significant ash cloud associated with the 0435 UTC event followed by at least 14 hours of continuous ash emission. The lack of a strong ash signature in satellite data suggest that the first two plumes were ash poor. Satellite data also show a large emission of SO2 that entered the stratosphere. Correlation of eruptive periods with deposits on the island is not yet possible, but it appears that pyroclastic flows were emplaced during all three explosive events and the surge and fall deposits accumulated during the continuous phase of the third event only. The role of external water is under investigation, and observations on August 22 and 23 indicated several streams flowing from the base of the crater walls into a shallow lake in the bottom of the 1 km2 crater. The surge and fall deposits exposed on Kasatochi Island contain abundant accretionary lapilli indicating water involvement during the emplacement of these deposits. Tephra deposits observed on islands southwest of Kasatochi range in thickness from 6 cm, 30 km from the volcano, to minor amounts on eastern Adak Island, 80 km to the southwest. A fishing boat about 13 km southwest of Kasatochi received about 12 cm of coarse ash to medium lapilli tephra fall. Tephra deposits observed at 5 locations southwest of Kasatochi consist of single beds of normally graded medium to coarse lapilli tephra fall. The lack of recognizable stratigraphic breaks in the tephra deposits suggests that they were the products of a single fall event, likely the third explosion that produced the most ash rich plume.

  6. A Versatile Time-Lapse Camera System Developed by the Hawaiian Volcano Observatory for Use at Kilauea Volcano, Hawaii

    USGS Publications Warehouse

    Orr, Tim R.; Hoblitt, Richard P.

    2008-01-01

    Volcanoes can be difficult to study up close. Because it may be days, weeks, or even years between important events, direct observation is often impractical. In addition, volcanoes are often inaccessible due to their remote location and (or) harsh environmental conditions. An eruption adds another level of complexity to what already may be a difficult and dangerous situation. For these reasons, scientists at the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO) have, for years, built camera systems to act as surrogate eyes. With the recent advances in digital-camera technology, these eyes are rapidly improving. One type of photographic monitoring involves the use of near-real-time network-enabled cameras installed at permanent sites (Hoblitt and others, in press). Time-lapse camera-systems, on the other hand, provide an inexpensive, easily transportable monitoring option that offers more versatility in site location. While time-lapse systems lack near-real-time capability, they provide higher image resolution and can be rapidly deployed in areas where the use of sophisticated telemetry required by the networked cameras systems is not practical. This report describes the latest generation (as of 2008) time-lapse camera system used by HVO for photograph acquisition in remote and hazardous sites on Kilauea Volcano.

  7. Tsunamis generated by eruptions from mount st. Augustine volcano, alaska.

    PubMed

    Kienle, J; Kowalik, Z; Murty, T S

    1987-06-12

    During an eruption of the Alaskan volcano Mount St. Augustine in the spring of 1986, there was concern about the possibility that a tsunami might be generated by the collapse of a portion of the volcano into the shallow water of Cook Inlet. A similar edifice collapse of the volcano and ensuing sea wave occurred during an eruption in 1883. Other sea waves resulting in great loss of life and property have been generated by the eruption of coastal volcanos around the world. Although Mount St. Augustine remained intact during this eruptive cycle, a possible recurrence of the 1883 events spurred a numerical simulation of the 1883 sea wave. This simulation, which yielded a forecast of potential wave heights and travel times, was based on a method that could be applied generally to other coastal volcanos. PMID:17793232

  8. Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002 Mw 7.9 Denali Fault Earthquake

    NASA Astrophysics Data System (ADS)

    Sanchez, J. J.; McNutt, S. R.

    2003-12-01

    On November 3, 2002 a Mw 7.9 earthquake ruptured segments of the Denali Fault and adjacent faults in interior Alaska providing a unique opportunity to look for intermediate-term (days to weeks) responses of Alaskan volcanoes to shaking from a large regional earthquake. The Alaska Volcano Observatory (AVO) monitors 24 volcanoes with seismograph networks. We examined one station per volcano, generally the closest to the vent (typically within 5 km) unless noise, or other factors made the data unusable. Data were digitally filtered between 0.8 and 5 Hz to enhance the signal-to-noise ratio. Data for the period four weeks before to four weeks after the Mw 7.9 earthquake were then plotted at a standard scale used for AVO routine monitoring. Mt. Veniaminof volcano, which has had recent mild eruptions and a rate of ten earthquakes per day on station VNNF, suffered a drop in seismicity by a factor of two after the earthquake; this lasted for 15 days. Wrangell, the closest volcano to the epicenter, had a background rate of about 16 earthquakes per day. Data from station WANC could not be measured for 3 days after the Mw 7.9 earthquake because the large number and size of aftershocks impeded identification of local earthquakes. For the following 30 days, however, its seismicity rate dropped by a factor of two. Seismicity then remained low for an additional 4 months at Wrangell, whereas that at Veniaminof returned to normal within weeks. The seismicity at both Mt. Veniaminof and Mt. Wrangell is dominated by low-frequency volcanic events. The detection thresholds for both seismograph networks are low and stations VNNF and WANC operated normally during the time of our study, thus we infer that the changes in seismicity may be related to the earthquake. It is known that Wrangell increased its heat output after the Mw 9.2 Alaska earthquake of 1964 and again after the Ms 7.1 St.Elias earthquake of 1979. The other volcanoes showed no changes in seismicity that can be attributable to the Mw 7.9 earthquake. We conclude that intermediate-term seismicity drops occurred at Mt. Wrangell and Mt. Veniaminof volcanoes, in strong contrast to cases of short-term seismicity increases observed at volcanic systems such as Katmai, Mount Rainier, Yellowstone, Mammoth Mountain, and the Geysers, Coso and Cerro Prieto (Mexico) geothermal fields. This suggests that fundamentally different mechanisms may be acting to modify seismicity at volcanoes.

  9. General Purpose Real-time Data Analysis and Visualization Software for Volcano Observatories

    NASA Astrophysics Data System (ADS)

    Cervelli, P. F.; Miklius, A.; Antolik, L.; Parker, T.; Cervelli, D.

    2011-12-01

    In 2002, the USGS developed the Valve software for management, visualization, and analysis of volcano monitoring data. In 2004, the USGS developed similar software, called Swarm, for the same purpose but specifically tailored for seismic waveform data. Since then, both of these programs have become ubiquitous at US volcano observatories, and in the case of Swarm, common at volcano observatories across the globe. Though innovative from the perspective of software design, neither program is methodologically novel. Indeed, the software can perform little more than elementary 2D graphing, along with basic geophysical analysis. So, why is the software successful? The answer is that both of these programs take data from the realm of discipline specialists and make them universally available to all observatory scientists. In short, the software creates additional value from existing data by leveraging the observatory's entire intellectual capacity. It enables rapid access to different data streams, and allows anyone to compare these data on a common time scale or map base. It frees discipline specialists from routine tasks like preparing graphics or compiling data tables, thereby making more time for interpretive efforts. It helps observatory scientists browse through data, and streamlines routine checks for unusual activity. It encourages a multi-parametric approach to volcano monitoring. And, by means of its own usefulness, it creates incentive to organize and capture data streams not yet available. Valve and Swarm are both written in Java, open-source, and freely available. Swarm is a stand-alone Java application. Valve is a system consisting of three parts: a web-based user interface, a graphing and analysis engine, and a data server. Both can be used non-interactively (e.g., via scripts) to generate graphs or to dump raw data. Swarm has a simple, built-in alarm capability. Several alarm algorithms have been built around Valve. Both programs remain under active development by the USGS and external collaborators. In this presentation, we will explain and diagram how the Valve and Swarm software work, show several real-life use cases, and address operational questions about how the software functions in an observatory environment.

  10. LARGE SCALE EDIFICE COLLAPSE AT REDOUBT VOLCANO, ALASKA

    NASA Astrophysics Data System (ADS)

    Beget, J. E.; Montanaro, C.; Trainor, T.; Bull, K.

    2009-12-01

    Redoubt Volcano has undergone multiple episodes of edifice collapse in postglacial time. New data from multi-beam scans of the floor of Cook Inlet offshore from Mt. Redoubt show that two of these events sent debris several kilometers into Cook Inlet. The late Pleistocene Harriet Point debris avalanche can be traced another 3 km beyond the modern shoreline. The Crescent River debris avalanche, the largest known collapse event, extended 4 km offshore, travelling more than 40 km downvalley from the volcano. About 900 years ago the most recent summit collapse sent a cohesive lahar down the Drift River to the shores of Cook Inlet, leaving a large summit collapse crater that is open to the north. The resultant summit morphology has directed virtually all subsequent lahars and pyroclastic flows down the Drift River. The 900 year-old Drift River lahar was at least 70 m thick at the foot of Redoubt Volcano and probably more than 15 m thick as it flowed down the Drift River, making it significantly larger then floods and lahars seen during recent historic eruptions. Deposits of two additional cohesive lahars are present in the Drift River, indicating at least five giant landslides of altered debris from the summit of Redoubt volcano have occurred in the last 3600 years. Steaming ground and altered rocks occur today at the summit of Redoubt Volcano, and x-ray diffraction studies of the 900-year-old deposit show it contains alunite, a clay mineral attributed to hydrothermal alteration of rocks at depths of several hundred meters within volcanic cones. These findings suggest that portions of the current summit of Redoubt Volcano are pervasively altered to clay up to hundreds of meters below the surface, and future summit collapses could potentially produce lahars much larger then any seen in historic time in the Drift River Valley. Very large lahars and debris avalanches might travel as far as several kilometers into Cook Inlet.

  11. Record of late holocene debris avalanches and lahars at Iliamna Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, C.F.; Miller, T.P.; Beget, J.E.

    2000-01-01

    Iliamna Volcano is a 3053-meter high, glaciated stratovolcano in the southern Cook Inlet region of Alaska and is one of seven volcanoes in this region that have erupted multiple times during the past 10,000 yr. Prior to our studies of Iliamna Volcano, little was known about the frequency, magnitude, and character of Holocene volcanic activity. Here we present geologic evidence of the most recent eruptive activity of the volcano and provide the first outline of Late Holocene debris-avalanche and lahar formation. Iliamna has had no documented historical eruptions but our recent field investigations indicate that the volcano has erupted at least twice in the last 300 yr. Clay-rich lahar deposits dated by radiocarbon to ???1300 and ???90 yr BP are present in two major valleys that head on the volcano. These deposits indicate that at least two large, possibly deep-seated, flank failures of the volcanic edifice have occurred in the last 1300 yr. Noncohesive lahar deposits likely associated with explosive pyroclastic eruptions date to 2400-1300,>1500,???300, and <305 yr BP. Debris-avalanche deposits from recent and historical small-volume slope failures of the hydrothermally altered volcanic edifice cover most of the major glaciers on the volcano. Although these deposits consist almost entirely of hydrothermally altered rock debris and snow and ice, none of the recently generated debris avalanches evolved to lahars. A clay-rich lahar deposit that formed <90??60 radiocarbon yr BP and entered the Johnson River Valley southeast of the volcano cannot be confidently related to an eruption of Iliamna Volcano, which has had no known historical eruptions. This deposit may record an unheralded debris avalanche and lahar. ?? 2000 Elsevier Science B.V. All rights reserved.

  12. Seismic observations of Redoubt Volcano, Alaska - 1989-2010 and a conceptual model of the Redoubt magmatic system

    USGS Publications Warehouse

    Power, John A.; Stihler, Scott D.; Chouet, Bernard A.; Haney, Matthew M.; Ketner, D.M.

    2013-01-01

    Seismic activity at Redoubt Volcano, Alaska, has been closely monitored since 1989 by a network of five to ten seismometers within 22 km of the volcano's summit. Major eruptions occurred in 1989-1990 and 2009 and were characterized by large volcanic explosions, episodes of lava dome growth and failure, pyroclastic flows, and lahars. Seismic features of the 1989-1990 eruption were 1) weak precursory tremor and a short, 23-hour-long, intense swarm of repetitive shallow long-period (LP) events centered 1.4 km below the crater floor, 2) shallow volcano-tectonic (VT) and hybrid earthquakes that separated early episodes of dome growth, 3) 13 additional swarms of LP events at shallow depths precursory to many of the 25 explosions that occurred over the more than 128 day duration of eruptive activity, and 4) a persistent cluster of VT earthquakes at 6 to 9 km depth. In contrast the 2009 eruption was preceded by a pronounced increase in deep-LP (DLP) events at lower crustal depths (25 to 38 km) that began in mid-December 2008, two months of discontinuous shallow volcanic tremor that started on January 23, 2009, a strong phreatic explosion on March 15, and a 58-hour-long swarm of repetitive shallow LP events. The 2009 eruption consisted of at least 23 major explosions between March 23 and April 5, again accompanied by shallow VT earthquakes, several episodes of shallow repetitive LP events and dome growth continuing until mid July. Increased VT earthquakes at 4 to 9 km depth began slowly in early April, possibly defining a mid-crustal magma source zone. Magmatic processes associated with the 2009 eruption seismically activated the same portions of the Redoubt magmatic system as the 1989-1990 eruption, although the time scales and intensity vary considerably among the two eruptions. The occurrence of precursory DLP events suggests that the 2009 eruption may have involved the rise of magma from lower crustal depths. Based on the evolution of seismicity during the 1989-1990 and 2009 eruptions the Redoubt magmatic system is envisioned to consist of a shallow system of cracks extending 1 to 2 km below the crater floor, a magma storage or source region at roughly 3 to 9 km depth, and a diffuse magma source region at 25 to 38 km depth. Close tracking of seismic activity allowed the Alaska Volcano Observatory to successfully issue warnings prior to many of the hazardous explosive events that occurred in 2009.

  13. Seismicity and stress in the vicinity of Mount Spurr volcano, south central Alaska

    NASA Astrophysics Data System (ADS)

    Jolly, Arthur D.; Page, Robert A.; Power, John A.

    1994-08-01

    Focal mechanism solutions and hypocenters for earthquakes near Mount Spurr volcano in south central Alaska reveal spatial perturbations in the regional stress field and in the maximum depth of seismicity. At the volcano, practically all the shocks during the dormant decade 1981-1991 have depths shallower than 5 km and are characterized by nearly pure normal slip. In contrast, earthquakes located outboard of the volcano concentrate in the depth range 3-18 km and exhibit predominantly strike slip, oblique reverse slip, or reverse slip. The regional stress field is characterized by subhorizontal maximum principal stress directed N 30 deg W, concordant with the direction of convergence between the North American and Pacific plates, whereas the maximum principal stress is probably more nearly vertical beneath the volcano. We suggest that the shoaling of seismicity beneath the volcano reflects localized elevation of the depth to the midcrustal transition from brittle failure to plastic flow. We attribute this localized elevation to relict magmatic heat associated with past volcanic eruptions. The available data are not sufficient to determine the cause of the suggested rotation of the maximum principal stress axis beneath the volcano; possible mechanisms include an increase in the vertical stress from the weight of the Mount Spurr massif and a decrease in the maximum horizontal stress associated with doming of the shallow crust from magmatic processes.

  14. Aseismic inflation of Westdahl volcano, Alaska, revealed by satellite radar interferometry

    USGS Publications Warehouse

    Lu, Zhiming; Wicks, C.; Dzurisin, D.; Thatcher, W.; Freymueller, J.T.; McNutt, S.R.; Mann, Dorte

    2000-01-01

    Westdahl volcano, located at the west end of Unimak Island in the central Aleutian volcanic arc, Alaska, is a broad shield that produced moderate-sized eruptions in 1964, 1978-79, and 1991-92. Satellite radar interferometry detected about 17 cm of volcano-wide inflation from September 1993 to October 1998. Multiple independent interferograms reveal that the deformation rate has not been steady; more inflation occurred from 1993 to 1995 than from 1995 to 1998. Numerical modeling indicates that a source located about 9 km beneath the center of the volcano inflated by about 0.05 km3 from 1993 to 1998. On the basis of the timing and volume of recent eruptions at Westdahl and the fact that it has been inflating for more than 5 years, the next eruption can be expected within the next several years.

  15. Preliminary Volcano-Hazard Assessment for the Tanaga Volcanic Cluster, Tanaga Island, Alaska

    USGS Publications Warehouse

    Coombs, Michelle L.; McGimsey, Robert G.; Browne, Brandon L.

    2007-01-01

    Summary of Volcano Hazards at Tanaga Volcanic Cluster The Tanaga volcanic cluster lies on the northwest part of Tanaga Island, about 100 kilometers west of Adak, Alaska, and 2,025 kilometers southwest of Anchorage, Alaska. The cluster consists of three volcanoes-from west to east, they are Sajaka, Tanaga, and Takawangha. All three volcanoes have erupted in the last 1,000 years, producing lava flows and tephra (ash) deposits. A much less frequent, but potentially more hazardous phenomenon, is volcanic edifice collapse into the sea, which likely happens only on a timescale of every few thousands of years, at most. Parts of the volcanic bedrock near Takawangha have been altered by hydrothermal activity and are prone to slope failure, but such events only present a local hazard. Given the volcanic cluster's remote location, the primary hazard from the Tanaga volcanoes is airborne ash that could affect aircraft. In this report, we summarize the major volcanic hazards associated with the Tanaga volcanic cluster.

  16. Characterization and Discrimination of Holocene Tephra Deposits at Mount Spurr Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Wallace, K. L.

    2002-12-01

    Correlation of distal tephra deposits with their respective sources is known to be problematic in the Cook Inlet region of Alaska. Existing correlations are heavily weighted on glass shard geochemistry, which is not always the most distinguishing characteristic in a region where eruption frequency is high and volcanoes are closely spaced. A multi-parameter approach to characterizing tephra deposits enhances the potential for recognition and long-distance correlation and provides an improved means of identifying source volcanoes. Previous studies were focused on providing a regional inventory of tephra deposits in the Cook Inlet region. These studies show that tephra erupted from Mount Spurr volcano and its satellite vent Crater Peak, are well preserved in this region (35 deposits in 6000 years) yet correlations using major-element glass geochemistry between distal tephra and proximal reference samples are often inconclusive. Tephra deposits preserved on the proximal (<10 km) flanks of Mount Spurr volcano and Crater Peak, constitute a record of explosive eruptions from these sources during the past ~5,000 years. This study provides detailed descriptions of all preserved tephra deposits from three proximal locations on the southern and southeastern flank of Mount Spurr volcano. These data suffice as a reference dataset for Mount Spurr volcano and Crater Peak tephra and include: 1) field characteristics (precise field location, photographs, unit thickness, grain shape, sorting, maximum grain size, and Munsell color), 2) mineral assemblages, 3) glass shard characteristics (photomicrographs and backscatter images), 4) major-element glass geochemistry, and 5) radiocarbon ages. Because no single set of parameters is known to characterize a tephra, a multi-parameter approach provides a more robust means of identifying source volcanoes in the Cook Inlet region and likely at other Aleutian arc regions. These data will be presented in a digital format for collaboration purposes so that they can be easily accessed, and manipulated to facilitate the likelihood and accuracy of future correlations.

  17. One hundred volatile years of volcanic gas studies at the Hawaiian Volcano Observatory: Chapter 7 in Characteristics of Hawaiian volcanoes

    USGS Publications Warehouse

    Sutton, A.J.; Elias, Tamar

    2014-01-01

    The first volcanic gas studies in Hawai‘i, beginning in 1912, established that volatile emissions from Kīlauea Volcano contained mostly water vapor, in addition to carbon dioxide and sulfur dioxide. This straightforward discovery overturned a popular volatile theory of the day and, in the same action, helped affirm Thomas A. Jaggar, Jr.’s, vision of the Hawaiian Volcano Observatory (HVO) as a preeminent place to study volcanic processes. Decades later, the environmental movement produced a watershed of quantitative analytical tools that, after being tested at Kīlauea, became part of the regular monitoring effort at HVO. The resulting volatile emission and fumarole chemistry datasets are some of the most extensive on the planet. These data indicate that magma from the mantle enters the shallow magmatic system of Kīlauea sufficiently oversaturated in CO2 to produce turbulent flow. Passive degassing at Kīlauea’s summit that occurred from 1983 through 2007 yielded CO2-depleted, but SO2- and H2O-rich, rift eruptive gases. Beginning with the 2008 summit eruption, magma reaching the East Rift Zone eruption site became depleted of much of its volatile content at the summit eruptive vent before transport to Pu‘u ‘Ō‘ō. The volatile emissions of Hawaiian volcanoes are halogen-poor, relative to those of other basaltic systems. Information gained regarding intrinsic gas solubilities at Kīlauea and Mauna Loa, as well as the pressure-controlled nature of gas release, have provided useful tools for tracking eruptive activity. Regular CO2-emission-rate measurements at Kīlauea’s summit, together with surface-deformation and other data, detected an increase in deep magma supply more than a year before a corresponding surge in effusive activity. Correspondingly, HVO routinely uses SO2 emissions to study shallow eruptive processes and effusion rates. HVO gas studies and Kīlauea’s long-running East Rift Zone eruption also demonstrate that volatile emissions can be a substantial volcanic hazard in Hawai‘i. From its humble beginning, trying to determine the chemical composition of volcanic gases over a century ago, HVO has evolved to routinely use real-time gas chemistry to track eruptive processes, as well as hazards.

  18. Three-dimensional velocity structure and high-precision earthquake relocations at Augustine, Akutan, and Makushin Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Syracuse, E. M.; Thurber, C. H.; Power, J. A.; Prejean, S. G.

    2010-12-01

    Alaska contains over 100 volcanoes, 21 of which have been active within the past 20 years, including Augustine in Cook Inlet, and Akutan and Makushin in the central Aleutian arc. We incorporate 14-15 years of earthquake data from the Alaska Volcano Observatory (AVO) to obtain P-wave velocity structure and high-precision earthquake locations at each volcano. At Augustine, most relocated seismicity is beneath the summit at an average depth of 0.6 km. In the weeks leading to the 2006 eruption, seismicity shallowed and focused on a NW-SE line, suggestive of an inflating dike. Through August 2006, intermittent seismicity was observed at 1 to 4.5 km depth, pointing to an association with the transport of magma. Active-source data are also incorporated into the tomographic inversion, illuminating a high-velocity column beneath the summit, and elevated velocities on the south flank. The high-velocity column surrounds the observed deeper seismicity and is likely due to intruded volcanic material. The elevated velocities on the south flank are associated with uplifted zeolitzed sandstones. Akutan most recently erupted in 1992, before the seismic network was installed. Most seismicity is above 9 km depth, with 10% occurring between 14 to30 km depth. Seismicity is separated into two main groups that dip away from the calderaone to the east and one to the west. The eastern group contains earthquakes from a swarm in early 1996 and the western group contains earthquakes from mid-1996 through the present that form rough lines radiating from the summit. Ongoing seismicity also occurs in a broader region beneath the caldera. Makushin most recently erupted in 1995, also prior to seismic monitoring by AVO. Relocations here show that most seismicity is at 3 to 13 km depth and either beneath the caldera or within one of two dipping clusters 20 km to the northeast. Additional seismicity occurs at up to 25 km depth beneath the summit, as well as scattered throughout the island at depths shallower than 15 km. Velocities beneath Akutan are lower than beneath Makushin at depths shallower than 7 km. Velocities are more varied beneath Makushin, with high velocities 14 km to the northeast of the summit surrounded by generally lower velocities above 5 km depth. Seismicity beneath the summit lies in a low velocity region, overlain by a northeastward-dipping high-velocity region that encompasses the cluster of dipping seismicity, indicating that these groups of earthquakes are likely caused by separate mechanisms.

  19. The evolution of seismic monitoring systems at the Hawaiian Volcano Observatory: Chapter 2 in Characteristics of Hawaiian volcanoes

    USGS Publications Warehouse

    Okubo, Paul G.; Nakata, Jennifer S.; Koyanagi, Robert Y.

    2014-01-01

    In the century since the Hawaiian Volcano Observatory (HVO) put its first seismographs into operation at the edge of Kīlauea Volcano’s summit caldera, seismic monitoring at HVO (now administered by the U.S. Geological Survey [USGS]) has evolved considerably. The HVO seismic network extends across the entire Island of Hawai‘i and is complemented by stations installed and operated by monitoring partners in both the USGS and the National Oceanic and Atmospheric Administration. The seismic data stream that is available to HVO for its monitoring of volcanic and seismic activity in Hawai‘i, therefore, is built from hundreds of data channels from a diverse collection of instruments that can accurately record the ground motions of earthquakes ranging in magnitude from <1 to ≥8. In this chapter we describe the growth of HVO’s seismic monitoring systems throughout its first hundred years of operation. Although other references provide specific details of the changes in instrumentation and data handling over time, we recount here, in more general terms, the evolution of HVO’s seismic network. We focus not only on equipment but also on interpretative products and results that were enabled by the new instrumentation and by improvements in HVO’s seismic monitoring, analytical, and interpretative capabilities implemented during the past century. As HVO enters its next hundred years of seismological studies, it is well situated to further improve upon insights into seismic and volcanic processes by using contemporary seismological tools.

  20. Headless Debris Flows From Mount Spurr Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    McGimsey, R. G.; Neal, C. A.; Waythomas, C. F.; Wessels, R.; Coombs, M. L.; Wallace, K. L.

    2004-12-01

    Sometime between June 20 and July 15, 2004-and contemporaneous with an increase of seismicity beneath the volcano, and elevated gas emissions-a sudden release of impounded water from the summit area of Mt. Spurr volcano produced about a dozen separate debris flow lobes emanating from crevasses and bergschrunds in the surface ice several hundred meters down the east-southeast flank from the summit. These debris flows were first observed by AVO staff on a July 15 overflight and appeared to represent a single flooding event; subsequent snow cover and limited accessibility have prevented direct investigation of these deposits. Observed from the air, they are dark, elongate lobate deposits, up to several hundred meters long and tens of meters wide, draping the steep (up to ~45 degree) slopes and cascading over and into crevasses. A water-rich phase from the flows continued down slope of the termini of several lobate deposits, eroding linear rills into the snow and ice down slope. We infer that the dark material composing these flows is likely remobilized coarse lapilli from the June 1992 tephra fall produced by an eruption of Crater Peak, a satellite vent of Mt. Spurr located 3.5 km to the south. Between 1 and 2 meters of basaltic andesite tephra fell directly on the Spurr summit during the 1992 eruption. The exact mechanism for sudden release of water-laden remobilized tephra flows from the summit basin is not clear. However, observations in early August, 2004, of an 80 m x 110-m-wide pit in the summit area snow and ice suggest the possibility of a partial roof collapse of a summit meltwater basin, likely associated with subglacial melting due to recent heat flux. Such a collapse could have led to the hydraulic surge of meltwater, and rapid mixing with tephra to produce slurries. These slurries traveled down slope beneath the ice surface to emerge through existing crevasses and other easy points of exit on the steep inclines. Mount Spurr is an ice- and snow covered, Quaternary andesitic volcanic complex, comprising a centrally located dome (or stratocone) in a breached, 5-km-wide, glacier-filled caldera that dissects ancestral Mt. Spurr volcano. The summit of Mt. Spurr is 130 km west of Anchorage, AK and reaches 3,374 m in elevation. The summit dome complex is topographically asymmetric, with a steeper southwest side and a more gradually sloping northeast flank To our knowledge, this is the first time such debris flows have been observed near the summit of Mt. Spurr. However, the existence of ponded water near the summit may not be unique to 2004. A review of historical photographs and descriptions of the Spurr summit area indicates a dynamic environment that responds to complex variations in snowfall accumulation, solar radiation, and geothermal heat flux. Other authors have noted variations in summit snow pack and the ephemeral appearance of a snow-filled depression and possibly a water-filled pit in 1964 aerial photographs of the summit. The formation of these debris flows near the summit of Mt. Spurr in conjunction with elevated seismicity below the summit and the development of a collapse pit in summit ice cap suggest that increasing geothermal heat flux, possibly in combination with above normal temperatures and long periods of clear, sunny weather in the region is responsible.

  1. Microearthquakes at st. Augustine volcano, alaska, triggered by Earth tides.

    PubMed

    Mauk, F J; Kienle, J

    1973-10-26

    Microearthquake activity at St. Augustine volcano, located at the mouth of Cook Inlet in the Aleutian Islands, has been monitored since August 1970. Both before and after minor eruptive activity on 7 October 1971, numerous shallow-foci microearthquake swarms were recorded. Plots of the hourly frequency of microearthquakes often show a diurnal peaking of activity. A cross correlation of this activity with the calculated magnitudes of tidal acceleration exhibited two prominent phase relationships. The first, and slightly more predominant, phase condition is a phase delay in the microearthquake activity of approximately 1 hour from the time of maximum tidal acceleration. This is thought to be a direct microearthquake-triggering effect caused by tidal stresses. The second is a phase delay in the microearthquake activity of approximately 5 hours, which correlates well with the time of maximum oceanic tidal loading. Correlation of the individual peaks of swarm activity with defined components of the tides suggests that it may be necessary for tidal stressing to have a preferential orientation in order to be an effective trigger of microearthquakes. PMID:17841318

  2. Global Positioning System (GPS) survey of Augustine Volcano, Alaska, August 3-8, 2000: data processing, geodetic coordinates and comparison with prior geodetic surveys

    USGS Publications Warehouse

    Pauk, Benjamin A.; Power, John A.; Lisowski, Mike; Dzurisin, Daniel; Iwatsubo, Eugene Y.; Melbourne, Tim

    2001-01-01

    Between August 3 and 8,2000,the Alaska Volcano Observatory completed a Global Positioning System (GPS) survey at Augustine Volcano, Alaska. Augustine is a frequently active calcalkaline volcano located in the lower portion of Cook Inlet (fig. 1), with reported eruptions in 1812, 1882, 1909?, 1935, 1964, 1976, and 1986 (Miller et al., 1998). Geodetic measurements using electronic and optical surveying techniques (EDM and theodolite) were begun at Augustine Volcano in 1986. In 1988 and 1989, an island-wide trilateration network comprising 19 benchmarks was completed and measured in its entirety (Power and Iwatsubo, 1998). Partial GPS surveys of the Augustine Island geodetic network were completed in 1992 and 1995; however, neither of these surveys included all marks on the island.Additional GPS measurements of benchmarks A5 and A15 (fig. 2) were made during the summers of 1992, 1993, 1994, and 1996. The goals of the 2000 GPS survey were to:1) re-measure all existing benchmarks on Augustine Island using a homogeneous set of GPS equipment operated in a consistent manner, 2) add measurements at benchmarks on the western shore of Cook Inlet at distances of 15 to 25 km, 3) add measurements at an existing benchmark (BURR) on Augustine Island that was not previously surveyed, and 4) add additional marks in areas of the island thought to be actively deforming. The entire survey resulted in collection of GPS data at a total of 24 sites (fig. 1 and 2). In this report we describe the methods of GPS data collection and processing used at Augustine during the 2000 survey. We use this data to calculate coordinates and elevations for all 24 sites surveyed. Data from the 2000 survey is then compared toelectronic and optical measurements made in 1988 and 1989. This report also contains a general description of all marks surveyed in 2000 and photographs of all new marks established during the 2000 survey (Appendix A).

  3. Reevaluation of tsunami formation by debris avalanche at Augustine Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, C.F.

    2000-01-01

    Debris avalanches entering the sea at Augustine Volcano, Alaska have been proposed as a mechanism for generating tsunamis. Historical accounts of the 1883 eruption of the volcano describe 6- to 9-meter-high waves that struck the coastline at English Bay (Nanwalek), Alaska about 80 kilometers east of Augustine Island. These accounts are often cited as proof that volcanigenic tsunamis from Augustine Volcano are significant hazards to the coastal zone of lower Cook Inlet. This claim is disputed because deposits of unequivocal tsunami origin are not evident at more than 50 sites along the lower Cook Inlet coastline where they might be preserved. Shallow water (<25 m) around Augustine Island, in the run-out zone for debris avalanches, limits the size of an avalanche-caused wave. If the two most recent debris avalanches, Burr Point (A.D. 1883) and West Island (<500 yr. B.P.) were traveling at velocities in the range of 50 to 100 meters per second, the kinetic energy of the avalanches at the point of impact with the ocean would have been between 1014 and 1015 joules. Although some of this energy would be dissipated through boundary interactions and momentum transfer between the avalanche and the sea, the initial wave should have possessed sufficient kinetic energy to do geomorphic work (erosion, sediment transport, formation of wave-cut features) on the coastline of lowwer Cook Inlet. Because widespread evidence of the effects of large waves cannot be found, it appears that the debris avalanches could not have been traveling very fast when they entered the sea, or they happened during low tide and displaced only small volumes of water. In light of these results, the hazard from volcanigenic tsunamis from Augustine Volcano appears minor, unless a very large debris avalanche occurs at high tide.

  4. The Changing Role of the Hawaiian Volcano Observatory within the Volcanological Community through its 100 year history

    NASA Astrophysics Data System (ADS)

    Kauahikaua, J. P.; Poland, M. P.

    2011-12-01

    When Thomas Jaggar, Jr., founded the Hawaiian Volcano Observatory in 1912, he wanted to "keep and publish careful records, invite the whole world of science to co-operate, and interest the business man." After studying the disastrous volcanic eruption at Martinique and Naples and the destructive earthquakes at Messina and the Caribbean Ocean, he saw observatories with these goals as a way to understand and mitigate these hazards. Owing to frequent eruptions, ease of access, and continuous record of activity (since January 17, 1912), Kilauea Volcano has been the focus for volcanological study by government, academic, and international investigators. New volcano monitoring techniques have been developed and tested on Hawaiian volcanoes and exported worldwide. HVO has served as a training ground for several generations of volcanologists; many have contributed to volcano research and hazards mitigation around the world. In the coming years, HVO and the scientific community will benefit from recent upgrades in our monitoring network. HVO had the first regional seismic network in the US and it will be fully digital; continuous GPS, tilt, gravity, and strain data already complement the seismic data; an array of infrared and visual cameras simultaneously track geologic surface changes. Scientifically, HVO scientists and their colleagues are making great advances in understanding explosive basaltic eruptions, volcanic gas emission and dispersion and its hazards, and lava flow mechanics with these advanced instruments. Activity at Hawaiian volcanoes continues to provide unparalleled opportunities for research and education, made all the more valuable by HVO's scientific legacy.

  5. Volcano seismology from around the world: Case studies from Mount Pinatubo (Philippines) Galeras (Colombia), Mount Wrangell and Mount Veniaminof (Alaska)

    NASA Astrophysics Data System (ADS)

    Sanchez-Aguilar, John Jairo

    A compilation of research papers in volcano seismology is presented: (1) to study the configuration of magma systems beneath volcanoes, (2) to describe unexpected effects of the shaking from a regional earthquake on volcanic systems, and (3) to integrate seismicity investigations into a conceptual model for the magma system of a volcano. This work was undertaken because much research in volcano seismology is needed to help in hazard assessment. The possible configuration of magma systems beneath Mount Pinatubo, Philippines, and Galeras Volcano, Colombia, is studied with b-value mapping. We suggest models for earthquake-volcanoes interactions by studying the declines in local seismicity at Mt. Wrangell and Mt. Veniaminof, Alaska, following the 3 November 2002 Denali Fault Earthquake (DFE). Finally, a model for the magmatic-hydrothermal system beneath Mt. Veniaminof is proposed by deriving a velocity model and relocating the earthquakes, and by studying the temporal changes of frequencies and attenuation (Q) at the source of long-period (LP) events. Results from b-value mapping confirm that volcanoes are characterized by localized zones of high b-values, and also indicate that the internal structure of volcanoes is variable. Analyses of the background seismicity at Mt. Veniaminof suggest that earthquakes result from locally-induced stresses and that LP events may represent the response of a shallow hydrothermal system to heat input from below. The study of declines in seismicity at Mt. Wrangell and Mt. Veniaminof volcanoes following the DFE indicates that the dynamic shaking from regional shocks can physically damage a volcano and together with the static stress changes can affect the local seismicity for extended periods. We conclude that the use of simple methods allows a better understanding of the seismicity at volcanoes in Alaska, but most importantly in developing countries where the small number of seismograph stations puts challenging limitations for research.

  6. Volcano-ice interactions precursory to the 2009 eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Bleick, Heather A.; Coombs, Michelle L.; Cervelli, Peter F.; Bull, Katharine F.; Wessels, Rick L.

    2013-06-01

    In late summer of 2008, after nearly 20 years of quiescence, Redoubt Volcano began to show signs of abnormal heat flow in its summit crater. In the months that followed, the excess heat triggered melting and ablation of Redoubt's glaciers, beginning at the summit and propagating to lower elevations as the unrest accelerated. A variety of morphological changes were observed, including the creation of ice cauldrons, areas of wide-spread subsidence, punctures in the ice carved out by steam, and deposition from debris flows. In this paper, we use visual observations, satellite data, and a high resolution digital elevation model of the volcanic edifice to calculate ice loss at Redoubt as a function of time. Our aim is to establish from this time series a proxy for heat flow that can be compared to other data sets collected along the same time interval. Our study area consists of the Drift glacier, which flows from the summit crater down the volcano's north slope, and makes up about one quarter of Redoubt's total ice volume of ~ 4 km3. The upper part of the Drift glacier covers the area of recent volcanism, making this part of ice mass most susceptible to the effect of volcanic heating. Moreover, melt water and other flows are channeled down the Drift glacier drainage by topography, leaving the remainder of Redoubt's ice mantle relatively unaffected. The rate of ice loss averaged around 0.1 m3/s over the last four months of 2008, accelerated to over twenty times this value by February 2009, and peaked at greater than 22 m3/s, just prior to the first major explosion on March 22, 2009. We estimate a cumulative ice loss over this period of about 35 million cubic meters (M m3).

  7. The New USGS Volcano Hazards Program Web Site

    NASA Astrophysics Data System (ADS)

    Venezky, D. Y.; Graham, S. E.; Parker, T. J.; Snedigar, S. F.

    2008-12-01

    The U.S. Geological Survey's (USGS) Volcano Hazard Program (VHP) has launched a revised web site that uses a map-based interface to display hazards information for U.S. volcanoes. The web site is focused on better communication of hazards and background volcano information to our varied user groups by reorganizing content based on user needs and improving data display. The Home Page provides a synoptic view of the activity level of all volcanoes for which updates are written using a custom Google® Map. Updates are accessible by clicking on one of the map icons or clicking on the volcano of interest in the adjacent color-coded list of updates. The new navigation provides rapid access to volcanic activity information, background volcano information, images and publications, volcanic hazards, information about VHP, and the USGS volcano observatories. The Volcanic Activity section was tailored for emergency managers but provides information for all our user groups. It includes a Google® Map of the volcanoes we monitor, an Elevated Activity Page, a general status page, information about our Volcano Alert Levels and Aviation Color Codes, monitoring information, and links to monitoring data from VHP's volcano observatories: Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Long Valley Observatory (LVO), Hawaiian Volcano Observatory (HVO), and Yellowstone Volcano Observatory (YVO). The YVO web site was the first to move to the new navigation system and we are working on integrating the Long Valley Observatory web site next. We are excited to continue to implement new geospatial technologies to better display our hazards and supporting volcano information.

  8. Hawaiian Volcano Observatory summary 100; Part 1, seismic data, January to December 2000

    USGS Publications Warehouse

    Nakata, Jennifer S.

    2001-01-01

    The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year and a chronological narrative describing the volcanic events. The seismic summary is offered without interpretation as a source of preliminary data. It is complete in the sense that all data for events of M≥1.5 routinely gathered by the Observatory are included. The emphasis in collection of tilt and deformation data has shifted from quarterly measurements at a few water-tube tilt stations (“wet” tilt) to a larger number of continuously recording borehole tiltmeters, repeated measurements at numerous spirit-level tilt stations (“dry” tilt), and surveying of level and trilateration networks. Because of the large quantity of deformation data now gathered and differing schedules of data reduction, the seismic and deformation summaries are published separately. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data dictated an annual publication beginning with Summary 74 for the year 1974. Summary 86 (the introduction of CUSP at HVO) includes a description of the seismic instrumentation, calibration, and processing used in recent years. The present summary includes enough background information on the seismic network and processing to allow use of the data and to provide an understanding of how they were gathered.

  9. Hawaiian Volcano Observatory summary 101: Part 1, seismic data, January to December 2001

    USGS Publications Warehouse

    Nakata, Jennifer S.; Chronological summary by Heliker, C.

    2002-01-01

    The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year and a chronological narrative describing the volcanic events. The seismic summary is offered without interpretation as a source of preliminary data. It is complete in the sense that all data for events of M>1.5 routinely gathered by the Observatory are included. The emphasis in collection of tilt and deformation data has shifted from quarterly measurements at a few water-tube tilt stations ("wet" tilt) to a larger number of continuously recording borehole tiltmeters, repeated measurements at numerous spirit-level tilt stations ("dry" tilt), and surveying of level and trilateration networks. Because of the large quantity of deformation data now gathered and differing schedules of data reduction, the seismic and deformation summaries are published separately. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data dictated an annual publication beginning with Summary 74 for the year 1974. Summary 86 (the introduction of CUSP at HVO) includes a description of the seismic instrumentation, calibration, and processing used in recent years. The present summary includes enough background information on the seismic network and processing to allow use of the data and to provide an understanding of how they were gathered.

  10. Hawaiian volcano observatory summary 103; Part I, seismic data, January to December 2003

    USGS Publications Warehouse

    Nakata, Jennifer S.; Heliker, C.; Orr, T.; Hoblitt, R.

    2004-01-01

    The Hawaiian Volcano Observatory (HVO) summary presents seismic data gathered during the year and a chronological narrative describing the volcanic events. The seismic summary is offered without interpretation as a source of preliminary data. It is complete in the sense that most data for events of M= 1.5 routinely gathered by the Observatory are included. The emphasis in collection of tilt and deformation data has shifted from quarterly measurements at a few water-tube tilt stations ('wet' tilt) to a larger number of continuously recording borehole tiltmeters, repeated measurements at numerous spirit-level tilt stations ('dry' tilt), and surveying of level and trilateration networks. Because of the large quantity of deformation data now gathered and differing schedules of data reduction, the seismic and deformation summaries are published separately. The HVO summaries have been published in various forms since 1956. Summaries prior to 1974 were issued quarterly, but cost, convenience of preparation and distribution, and the large quantities of data dictated an annual publication beginning with Summary 74 for the year 1974. Summary 86 (the introduction of CUSP at HVO) includes a description of the seismic instrumentation, calibration, and processing used in recent years. The present summary includes background information on the seismic network and processing to allow use of the data and to provide an understanding of how they were gathered.

  11. Statistical forecasting of repetitious dome failures during the waning eruption of Redoubt Volcano, Alaska, February April 1990

    NASA Astrophysics Data System (ADS)

    Page, Robert A.; Lahr, John C.; Chouet, Bernard A.; Power, John A.; Stephens, Christopher D.

    1994-08-01

    The waning phase of the 1989-1990 eruption of Redoubt Volcano in the Cook Inlet region of south-central Alaska comprised a quasi-regular pattern of repetitious dome growth and destruction that lasted from February 15 to late April 1990. The dome failures produced ash plumes hazardous to airline traffic. In response to this hazard, the Alaska Volcano Observatory sought to forecast these ash-producing events using two approaches. One approach built on early successes in issuing warnings before major eruptions on December 14, 1989 and January 2, 1990. These warnings were based largely on changes in seismic activity related to the occurrence of precursory swarms of long-period seismic events. The search for precursory swarms of long-period seismicity was continued through the waning phase of the eruption and led to warnings before tephra eruptions on March 23 and April 6. The observed regularity of dome failures after February 15 suggested that a statistical forecasting method based on a constant-rate failure model might also be successful. The first statistical forecast was issued on March 16 after seven events had occurred, at an average interval of 4.5 days. At this time, the interval between dome failures abruptly lengthened. Accordingly, the forecast was unsuccessful and further forecasting was suspended until the regularity of subsequent failures could be confirmed. Statistical forecasting resumed on April 12, after four dome failure episodes separated by an average of 7.8 days. One dome failure (April 15) was successfully forecast using a 70% confidence window, and a second event (April 21) was narrowly missed before the end of the activity. The cessation of dome failures after April 21 resulted in a concluding false alarm. Although forecasting success during the eruption was limited, retrospective analysis shows that early and consistent application of the statistical method using a constant-rate failure model and a 90% confidence window could have yielded five successful forecasts and two false alarms; no events would have been missed. On closer examination, the intervals between successive dome failures are not uniform but tend to increase with time. This increase attests to the continuous, slowly decreasing supply of magma to the surface vent during the waning phase of the eruption. The domes formed in a precarious position in a breach in the summit crater rim where they were susceptible to gravitational collapse. The instability of the February 15-April 21 domes relative to the earlier domes is attributed to reaming the lip of the vent by a laterally directed explosion during the major dome-destroying eruption of February 15, a process which would leave a less secure foundation for subsequent domes.

  12. International Volcanological Field School in Kamchatka and Alaska: Experiencing Language, Culture, Environment, and Active Volcanoes

    NASA Astrophysics Data System (ADS)

    Eichelberger, J. C.; Gordeev, E.; Ivanov, B.; Izbekov, P.; Kasahara, M.; Melnikov, D.; Selyangin, O.; Vesna, Y.

    2003-12-01

    The Kamchatka State University of Education, University of Alaska Fairbanks, and Hokkaido University are developing an international field school focused on explosive volcanism of the North Pacific. An experimental first session was held on Mutnovsky and Gorely Volcanoes in Kamchatka during August 2003. Objectives of the school are to:(1) Acquaint students with the chemical and physical processes of explosive volcanism, through first-hand experience with some of the most spectacular volcanic features on Earth; (2) Expose students to different concepts and approaches to volcanology; (3) Expand students' ability to function in a harsh environment and to bridge barriers in language and culture; (4) Build long-lasting collaborations in research among students and in teaching and research among faculty in the North Pacific region. Both undergraduate and graduate students from Russia, the United States, and Japan participated. The school was based at a mountain hut situated between Gorely and Mutnovsky Volcanoes and accessible by all-terrain truck. Day trips were conducted to summit craters of both volcanoes, flank lava flows, fumarole fields, ignimbrite exposures, and a geothermal area and power plant. During the evenings and on days of bad weather, the school faculty conducted lectures on various topics of volcanology in either Russian or English, with translation. Although subjects were taught at the undergraduate level, lectures led to further discussion with more advanced students. Graduate students participated by describing their research activities to the undergraduates. A final session at a geophysical field station permitted demonstration of instrumentation and presentations requiring sophisticated graphics in more comfortable surroundings. Plans are underway to make this school an annual offering for academic credit in the Valley of Ten Thousand Smokes, Alaska and in Kamchatka. The course will be targeted at undergraduates with a strong interest in and aptitude for the physical sciences, not necessarily volcanology. It will also serve as an entry point for students wishing to make extended exchange visits to the Russian Far East or Alaska, and to graduate students in volcanology wishing to undertake thesis research in North Pacific volcanism. The school represents the first educational effort of the newly established Japan Kamchatka Alaska Subduction Project (JKASP), which seeks to bring scientists of our three nations together in the study of one shared geophysical province, the Kuril-Kamchatka-Aleutian Arcs.

  13. Low pressure fractionation in arc volcanoes: an example from Augustine Volcano, Alaska

    SciTech Connect

    Daley, E.E.; Swanson, S.E.

    1985-01-01

    Augustine Volcano, situated between the Cook and Katmai segments of the Eastern Aleutian Volcanic Arc, has erupted 5 times since its discovery in 1778. Eruptions are characterized by early vent-clearing eruptions with accompanying pyroclastic flows followed by dome-building and more pyroclastic flows. Bulk rock chemistry of historic and prehistoric lavas shows little variability. The lavas are calc-alkaline, low to medium K, porphyritic acid andesites, rare basalt, and minor dacite pumice. FeO*/MgO averages 1.6 over this silica range. Plagioclase phenocrysts show complicated zoning patterns, but olivine, orthopyroxene, and clinopyroxene phenocrysts show little compositional variation. Hornblende, where present, is ubiquitously oxidized and was clearly out of equilibrium during the last stages of fractionation. Evolved liquid compositions of vitriophyric domes are rhyolitic, and of pumices are slightly less evolved suggesting that individual eruptions become more fractionated with time. Comparison of glass compositions with experimental results is consistent with low pressure fractionation of a relatively dry silicate melt. Disequilibrium of amphiboles and the evolved nature of glasses indicate that shallow level fractionation plays a significant role in the evolution of Augustine magmas. This model is consistent with a shallow magma chamber inferred from geophysical models of the Augustine system and also with its simple, predictable eruption pattern.

  14. Precursory seismicity associated with frequent, large ice avalanches on Iliamna Volcano, Alaska, USA

    USGS Publications Warehouse

    Caplan-Auerbach, Jacqueline; Huggel, C.

    2007-01-01

    Since 1994, at least six major (volume>106 m3) ice and rock avalanches have occurred on Iliamna volcano, Alaska, USA. Each of the avalanches was preceded by up to 2 hours of seismicity believed to represent the initial stages of failure. Each seismic sequence begins with a series of repeating earthquakes thought to represent slip on an ice-rock interface, or between layers of ice. This stage is followed by a prolonged period of continuous ground-shaking that reflects constant slip accommodated by deformation at the glacier base. Finally the glacier fails in a large avalanche. Some of the events appear to have entrained large amounts of rock, while others comprise mostly snow and ice. Several avalanches initiated from the same source region, suggesting that this part of the volcano is particularly susceptible to failure, possibly due to the presence of nearby fumaroles. Although thermal conditions at the time of failure are not well constrained, it is likely that geothermal energy causes melting at the glacier base, promoting slip and culminating in failure. The frequent nature and predictable failure sequence of Iliamna avalanches makes the volcano an excellent laboratory for the study of ice avalanches. The prolonged nature of the seismic signal suggests that warning may one day be given for similar events occurring in populated regions.

  15. Deformation of the Augustine Volcano, Alaska, 1992-2005, measured by ERS and ENVISAT SAR interferometry

    USGS Publications Warehouse

    Lee, C.-W.; Lu, Zhiming; Kwoun, Oh-Ig; Won, J.-S.

    2008-01-01

    The Augustine Volcano is a conical-shaped, active stratovolcano located on an island of the same name in Cook Inlet, about 290 km southwest of Anchorage, Alaska. Augustine has experienced seven significant explosive eruptions - in 1812, 1883, 1908, 1935, 1963, 1976, 1986, and in January 2006. To measure the ground surface deformation of the Augustine Volcano before the 2006 eruption, we applied satellite radar interferometry using Synthetic Aperture Radar (SAR) images from three descending and three ascending satellite tracks acquired by European Remote Sensing Satellite (ERS) 1 and 2 and the Environment Satellite (ENVISAT). Multiple interferograms were stacked to reduce artifacts caused by atmospheric conditions, and we used a singular value decomposition method to retrieve the temporal deformation history from several points on the island. Interferograms during 1992 and 2005 show a subsidence of about 1-3 cm/year, caused by the contraction of pyroclastic flow deposits from the 1986 eruption. Subsidence has decreased exponentially with time. Multiple interferograms between 1992 and 2005 show no significant inflation around the volcano before the 2006 eruption. The lack of a pre-eruption deformation signal suggests that the deformation signal from 1992 to August 2005 must have been very small and may.have been obscured by atmospheric delay artifacts. Copyright ?? The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.

  16. Volcano Seismology GEOS 671, A Graduate Course at the University of Alaska Fairbanks

    NASA Astrophysics Data System (ADS)

    McNutt, S. R.

    2002-05-01

    Volcano seismology is a discipline that straddles seismology and volcanology. It consists of an abundance of specialized knowledge that is not taught in traditional seismology courses, and does not exist in any single book or textbook. Hence GEOS 671 was developed starting in 1995. The following topics are covered in the course: history and organization of the subject; instruments and networks; seismic velocities of volcanic materials; terminology and event classification; swarms, magnitudes, energy, b-values, p-values; high frequency (VT, A-type) earthquakes; low frequency (LP, B-type, VLP) earthquakes; volcanic tremor; volcanic explosions (C-type); attenuation and noise at volcanoes; large earthquakes near volcanoes; cycles of volcanic activity; forecasting of eruptions and assessment of eruptions in progress; magma chambers, S-wave screening, and tomography; selected topics, such as probability, chaos, lightning, and modelling. Case studies help illuminate the basic principles by providing benchmarks and specific examples of important trends, patterns, or dominant processes. Case studies include: Arenal 1968-2002; Redoubt 1989-90; Spurr 1992; Usu 1977; Mount St. Helens 1980; Kilauea 1983; Izu-Oshima 1986; Galeras 1988-1993; Long Valley 1980-1989; Pinatubo 1991; and Rabaul 1981-1994. The students each present two case studies during the semester. GEOS 671 has been taught 4 times (every other year) with 4-8 students each time. At least one student term paper from each class has been expanded into a published work. To keep up with new research, about 15 percent new material is added each time the course is taught. Finally, Alaska is home to 41 historically active volcanoes (80 Holocene) of which 23 are monitored with seismic networks. Students have a strong chance to apply what they learn in the course during real eruptive crises.

  17. Volcano hazards and potential risks on St. Paul Island, Pribilof Islands, Bering Sea, Alaska

    NASA Astrophysics Data System (ADS)

    Feeley, T. C.; Winer, G. S.

    2009-05-01

    Volcano hazards and potential risks on St. Paul Island, Alaska, are assessed on the basis of the recent volcanic history of the island. The long-term frequency of volcanic eruptions is estimated using a count of 40 identifiable vents considered to represent separate eruptions. Assuming regular temporal spacing of these events during the period 360,000 to 3230 y.b.p., the estimated mean recurrence time is 0.11 × 10 - 3 eruption/year and the eruptive interval is approximately 8900 years. Volcano hazards on St. Paul are associated exclusively with the eruption of low viscosity alkali basaltic magma. The most important are lava flows, tephra fallout, and base surges. Other hazards include volcanic gases, seismicity and ground deformation associated with dike intrusion beneath rift zones, and explosive lava-water interactions along coastal regions and water-saturated ground. The general characteristics of past volcanism on St. Paul indicate that the most likely styles of future eruptions will be (1) Hawaiian-style eruptions with fire fountains and pahoehoe lava flows issuing from one of two polygenetic shield volcanoes on the island; (2) Strombolian-style, scoria cone-building eruptions with associated tephra fallout and eruption of short pahoehoe lava flows; and (3) explosive Surtseyan-style, phreatomagmatic eruptions initiating at some point along St. Paul's insular shelf. Given the relatively restricted range in volcanic phenomena on St. Paul, the most significant question regarding volcano hazard and risk assessment is whether future eruptions will be confined to the same region on the island as the most recent activity. If future activity follows the recent past, resulting volcano hazards will most likely be located at inland areas sufficiently far from habitation that they will pose little threat to life or property. An important caveat, however, is that St. Paul is constructed almost entirely from the products of volcanic eruptions with vents located all over the island. Thus, a new vent could form at any place on the island, including St. Paul's insular shelf and areas farther offshore. Because of the remote location of St. Paul in the storm-lashed Bering Sea, risks related to volcano hazards may be greater than they would be in a different setting where more stable meteorological conditions prevail and access by monitoring and relief groups is less challenging.

  18. Preliminary volcano-hazard assessment for the Katmai volcanic cluster, Alaska

    USGS Publications Warehouse

    Fierstein, Judy; Hildreth, Wes

    2000-01-01

    The world’s largest volcanic eruption of the 20th century broke out at Novarupta (fig. 1) in June 1912, filling with hot ash what came to be called the Valley of Ten Thousand Smokes and spreading downwind more fallout than all other historical Alaskan eruptions combined. Although almost all the magma vented at Novarupta, most of it had been stored beneath Mount Katmai 10 km away, which collapsed during the eruption. Airborne ash from the 3-day event blanketed all of southern Alaska, and its gritty fallout was reported as far away as Dawson, Ketchikan, and Puget Sound (fig. 21). Volcanic dust and sulfurous aerosol were detected within days over Wisconsin and Virginia; within 2 weeks over California, Europe, and North Africa; and in latter-day ice cores recently drilled on the Greenland ice cap. There were no aircraft in Alaska in 1912—fortunately! Corrosive acid aerosols damage aircraft, and ingestion of volcanic ash can cause abrupt jet-engine failure. Today, more than 200 flights a day transport 20,000 people and a fortune in cargo within range of dozens of restless volcanoes in the North Pacific. Air routes from the Far East to Europe and North America pass over and near Alaska, many flights refueling in Anchorage. Had this been so in 1912, every airport from Dillingham to Dawson and from Fairbanks to Seattle would have been enveloped in ash, leaving pilots no safe option but to turn back or find refuge at an Aleutian airstrip west of the ash cloud. Downwind dust and aerosol could have disrupted air traffic anywhere within a broad swath across Canada and the Midwest, perhaps even to the Atlantic coast. The great eruption of 1912 focused scientific attention on Novarupta, and subsequent research there has taught us much about the processes and hazards associated with such large explosive events (Fierstein and Hildreth, 1992). Moreover, work in the last decade has identified no fewer than 20 discrete volcanic vents within 15 km of Novarupta (Hildreth and others, 1999, 2000, 2001; Hildreth and Fierstein, 2000), only half of which had been named previously—the four stratovolcanoes Mounts Katmai, Mageik, Martin, and Griggs; the cone cluster called Trident Volcano; Snowy Mountain; and the three lava domes Novarupta, Mount Cerberus, and Falling Mountain. The most recent eruptions were from Trident Volcano (1953–74), but there have been at least eight other, probably larger, explosive events from the volcanoes of this area in the past 10,000 years. This report summarizes what has been learned about the volcanic histories and styles of eruption of all these volcanoes. Many large earthquakes occurred before and during the 1912 eruption, and the cluster of Katmai volcanoes remains seismically active. Because we expect an increase in seismicity before eruptions, seismic monitoring efforts to detect volcanic unrest and procedures for eruption notification and dissemination of information are included in this report. Most at risk from future eruptions of the Katmai volcanic cluster are (1) air-traffic corridors of the North Pacific, including those approaching Anchorage, one of the Pacific’s busiest international airports, (2) several regional airports and military air bases, (3) fisheries and navigation on the Naknek Lake system and Shelikof Strait, (4) pristine wildlife habitat, particularly that of the Alaskan brown bear, and (5) tourist facilities in and near Katmai National Park.

  19. Volcanoes

    ERIC Educational Resources Information Center

    Kunar, L. N. S.

    1975-01-01

    Describes the forces responsible for the eruptions of volcanoes and gives the physical and chemical parameters governing the type of eruption. Explains the structure of the earth in relation to volcanoes and explains the location of volcanic regions. (GS)

  20. Volcanoes

    SciTech Connect

    Decker, R.W.; Decker, B.

    1989-01-01

    This book describes volcanoes although the authors say they are more to be experienced than described. This book poses more question than answers. The public has developed interest and awareness in volcanism since the first edition eight years ago, maybe because since the time 120 volcanoes have erupted. Of those, the more lethal eruptions were from volcanoes not included in the first edition's World's 101 Most Notorious Volcanoes.

  1. Volcanoes.

    ERIC Educational Resources Information Center

    Tilling, Robert I.

    One of a series of general interest publications on science topics, this booklet provides a non-technical introduction to the subject of volcanoes. Separate sections examine the nature and workings of volcanoes, types of volcanoes, volcanic geological structures such as plugs and maars, types of eruptions, volcanic-related activity such as geysers…

  2. EarthScope's Plate Boundary Observatory in Alaska: Building on Existing Infrastructure to Provide a Platform for Integrated Research and Hazard-monitoring Efforts

    NASA Astrophysics Data System (ADS)

    Boyce, E. S.; Bierma, R. M.; Willoughby, H.; Feaux, K.; Mattioli, G. S.; Enders, M.; Busby, R. W.

    2014-12-01

    EarthScope's geodetic component in Alaska, the UNAVCO-operated Plate Boundary Observatory (PBO) network, includes 139 continuous GPS sites and 41 supporting telemetry relays. These are spread across a vast area, from northern AK to the Aleutians. Forty-five of these stations were installed or have been upgraded in cooperation with various partner agencies and currently provide data collection and transmission for more than one group. Leveraging existing infrastructure normally has multiple benefits, such as easier permitting requirements and costs savings through reduced overall construction and maintenance expenses. At some sites, PBO-AK power and communications systems have additional capacity beyond that which is needed for reliable acquisition of GPS data. Where permits allow, such stations could serve as platforms for additional instrumentation or real-time observing needs. With the expansion of the Transportable Array (TA) into Alaska, there is increased interest to leverage existing EarthScope resources for station co-location and telemetry integration. Because of the complexity and difficulty of long-term O&M at PBO sites, however, actual integration of GPS and seismic equipment must be considered on a case-by-case basis. UNAVCO currently operates two integrated GPS/seismic stations in collaboration with the Alaska Earthquake Center, and three with the Alaska Volcano Observatory. By the end of 2014, PBO and TA plan to install another four integrated and/or co-located geodetic and seismic systems. While three of these are designed around existing PBO stations, one will be a completely new TA installation, providing PBO with an opportunity to expand geodetic data collection in Alaska within the limited operations and maintenance phase of the project. We will present some of the design considerations, outcomes, and lessons learned from past and ongoing projects to integrate seismometers and other instrumentation at PBO-Alaska stations. Developing the PBO network as a platform for ongoing research and hazard monitoring equipment may also continue to serve the needs of the research community and the public beyond the sun-setting and completion of EarthScope science plan in 2018.

  3. Adakitic volcanism in the eastern Aleutian arc: Petrology and geochemistry of Hayes volcano, Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    McHugh, K.; Hart, W. K.; Coombs, M. L.

    2012-12-01

    Located in south-central Alaska, 135 km northwest of Anchorage, Hayes volcano is responsible for the most widespread tephra fall deposit in the regional Holocene record (~3,500 BP). Hayes is bounded to the west by the Cook Inlet volcanoes (CIV; Mt. Spurr, Redoubt, Iliamna, and Augustine) and separated from the nearest volcanism to the east, Mount Drum of the Wrangell Volcanic Field (WVF), by a 400 km-wide volcanic gap. We report initial results of the first systematic geochemical and petrologic study of Hayes volcano. Hayes eruptive products are calc-alkaline dacites and rhyolites that have anomalous characteristics within the region. Major and trace element analyses reveal that the Hayes rhyolites are more silicic (~74 wt. % SiO2) than compositions observed in other CIV, and its dacitic products possess the distinctive geochemical signatures of adakitic magmas. Key aspects of the Hayes dacite geochemistry include: 16.03 - 17.54 wt. % Al2O3, 0.97 - 2.25 wt. % MgO, Sr/Y = 60 - 78, Yb = 0.9 - 1.2 ppm, Ba/La = 31 - 79. Such signatures are consistent with melting of a metamorphosed basaltic source that leaves behind a residue of garnet ± amphibole ± pyroxene via processes such as melting of a subducting oceanic slab or underplated mafic lower crust, rather than flux melting of the mantle wedge by dehydration of the down-going slab. Additionally, Hayes tephras display a distinctive mineralogy of biotite with amphibole in greater abundance than pyroxene, a characteristic not observed at other CIV. Furthermore, Hayes rhyolites and dacites exhibit little isotopic heterogeneity (87Sr/86Sr = 0.70384 - 0.70395, 206Pb/204Pb = 18.866 - 18.889) suggesting these lavas originate from the same source. Hayes volcano is approximately situated above the western margin of the subducting Yakutat terrane and where the dip of the Pacific slab beneath Cook Inlet shallows northward. Due to its position along the margin of the subducting Yakutat terrane, it is plausible that Hayes magmas are the result of partial melting of this slab where thermal erosion and weakening of the crust occurs along the Pacific plate-Yakutat terrane transition. Additionally, flat slab subduction may be responsible for producing adakitic magmas by equilibration of the hydrous slab with ambient mantle temperatures. In contrast, it is possible that the adakitic signature at Hayes is from underplated mafic lower crust that melted as the result of pooling mantle melt at depth. Two volcanoes within the WVF, Mt. Drum and Mt. Churchill, are adakitic with an abundance of biotite and amphibole similar to Hayes volcano and have been suggested to have slab melt origins. Mt. Drum lavas have less radiogenic 87Sr/86Sr but overlapping 206Pb/204Pb signatures while Mt. Churchill, which approximately overlies the eastern edge of the Yakutat terrane, has similar 87Sr/86Sr compositions, but more radiogenic 206Pb/204Pb than Hayes. Mt. Spurr, the nearest CIV to Hayes volcano (90 km south), does not share its adakitic signature but exhibits overlapping, more heterogeneous isotopic compositions. Thus, understanding the petrogenetic history of Hayes volcano is essential not only to explain the development of an adakitic volcanic system but how this relates to regional, arc-wide volcanism.

  4. Modeled tephra ages from lake sediments, base of Redoubt Volcano, Alaska

    SciTech Connect

    Schiff, C J; Kaufman, D S; Wallace, K L; Werner, A; Ku, T L; Brown, T A

    2007-02-25

    A 5.6-m-long lake sediment core from Bear Lake, Alaska, located 22 km southeast of Redoubt Volcano, contains 67 tephra layers deposited over the last 8750 cal yr, comprising 15% of the total thickness of recovered sediment. Using 12 AMS {sup 14}C ages, along with the {sup 137}Cs and {sup 210}Pb activities of recent sediment, we evaluated different models to determine the age-depth relation of sediment, and to determine the age of each tephra deposit. The age model is based on a cubic smooth spline function that was passed through the adjusted tephra-free depth of each dated layer. The estimated age uncertainty of the 67 tephras averages {+-} 105 yr (1{sigma}). Tephra-fall frequency at Bear Lake was among the highest during the past 500 yr, with eight tephras deposited compared to an average of 3.7 per 500 yr over the last 8500 yr. Other periods of increased tephra fall occurred 2500-3500, 4500-5000, and 7000-7500 cal yr. Our record suggests that Bear Lake experienced extended periods (1000-2000 yr) of increased tephra fall separated by shorter periods (500-1000 yr) of apparent quiescence. The Bear Lake sediment core affords the most comprehensive tephrochronology from the base of the Redoubt Volcano to date, with an average tephra-fall frequency of once every 130 yr.

  5. Magma supply dynamics at Westdahl volcano, Alaska, modeled from satellite radar interferometry

    USGS Publications Warehouse

    Lu, Zhiming; Masterlark, Timothy; Dzurisin, D.; Rykhus, Russ; Wicks, C., Jr.

    2003-01-01

    A group of satellite radar interferograms that span the time period from 1991 to 2000 shows that Westdahl volcano, Alaska, deflated during its 1991-1992 eruption and is reinflating at a rate that could produce another eruption within the next several years. The rates of inflation and deflation are approximated by exponential decay functions having time constants of about 6 years and a few days, respectively. This behavior is consistent with a deep, constant-pressure magma source connected to a shallow reservoir by a magma-filled conduit. An elastic deformation model indicates that the reservoir is located about 6 km below sea level and beneath Westdahl Peak. We propose that the magma flow rate through the conduit is governed by the pressure gradient between the deep source and the reservoir. The pressure gradient, and hence the flow rate, are greatest immediately after eruptions. Pressurization of the reservoir decreases both the pressure gradient and the flow rate, but eventually the reservoir ruptures and an eruption or intrusion ensues. The eruption rate is controlled partly by the pressure gradient between the reservoir and surface, and therefore it, too, decreases with time. When the supply of eruptible magma is exhausted, the eruption stops, the reservoir begins to repressurize at a high rate, and the cycle repeats. This model might also be appropriate for other frequently active volcanoes with stable magma sources and relatively simple magma storage systems.

  6. Detecting hidden volcanic explosions from Mt. Cleveland Volcano, Alaska with infrasound and ground-couples airwaves

    USGS Publications Warehouse

    De Angelis, Slivio; Fee, David; Haney, Matthew; Schneider, David

    2012-01-01

    In Alaska, where many active volcanoes exist without ground-based instrumentation, the use of techniques suitable for distant monitoring is pivotal. In this study we report regional-scale seismic and infrasound observations of volcanic activity at Mt. Cleveland between December 2011 and August 2012. During this period, twenty explosions were detected by infrasound sensors as far away as 1827 km from the active vent, and ground-coupled acoustic waves were recorded at seismic stations across the Aleutian Arc. Several events resulting from the explosive disruption of small lava domes within the summit crater were confirmed by analysis of satellite remote sensing data. However, many explosions eluded initial, automated, analyses of satellite data due to poor weather conditions. Infrasound and seismic monitoring provided effective means for detecting these hidden events. We present results from the implementation of automatic infrasound and seismo-acoustic eruption detection algorithms, and review the challenges of real-time volcano monitoring operations in remote regions. We also model acoustic propagation in the Northern Pacific, showing how tropospheric ducting effects allow infrasound to travel long distances across the Aleutian Arc. The successful results of our investigation provide motivation for expanded efforts in infrasound monitoring across the Aleutians and contributes to our knowledge of the number and style of vulcanian eruptions at Mt. Cleveland.

  7. Comparison of Seismicity Preceding the 1989-1990 and 2009 Eruptions of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Wessale, M. S.; Pesicek, J. D.; Syracuse, E. M.; Thurber, C. H.; Deshon, H. R.; Power, J. A.; Prejean, S. G.

    2010-12-01

    Located 110 miles from Anchorage, Alaska, Redoubt Volcano is a significant hazard to the Cook Inlet region and overlying flight paths. The volcano has been continuously monitored by a 5 to 10-station seismic network since 1989. Previous work by DeShon et al. (2007) focused on reducing location errors of Redoubt earthquakes from 1989-2005 by computing a three-dimensional P wave velocity model using double-difference tomography combined with waveform cross-correlation techniques. We apply these same techniques to the Redoubt earthquake data from November 2005 to December 2009, including the spring 2009 eruption. Cross correlation and relocation analysis of the 2005-2009 data has yielded earthquake locations with improved clustering. A consistent pattern of a near-vertical alignment of hypocenters beneath the summit area, presumed to reflect a magma conduit, is present at the time of the major explosions occurring on March 23rd and 27th. Our ongoing analysis of the Redoubt earthquake data will focus on double-difference tomography that is expected to further improve the earthquake locations and provide a comparative data set for the 1989-1990 and 2009 eruptions.

  8. Three-dimensional P and S wave velocity structure of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Benz, H.M.; Chouet, B.A.; Dawson, P.B.; Lahr, J.C.; Page, R.A.; Hole, J.A.

    1996-01-01

    The three-dimensional P and S wave structure of Redoubt Volcano, Alaska, and the underlying crust to depths of 7-8 km is determined from 6219 P wave and 4008 S wave first-arrival times recorded by a 30-station seismograph network deployed on and around the volcano. First-arrival times are calculated using a finite-difference technique, which allows for flexible parameterization of the slowness model and easy inclusion of topography and source-receiver geometry. The three-dimensional P wave velocity structure and hypocenters are determined simultaneously, while the three-dimensional S wave velocity model is determined using the relocated seismicity and an initial S wave velocity model derived from the P wave velocity model assuming an average Vp/Vs ratio of 1.78. Convergence is steady with approximately 73% and 52% reduction in P and S wave arrival time RMS, respectively, after 10 iterations. The most prominent feature observed in the three-dimensional velocity models derived for both P and S waves is a relative low-velocity, near-vertical, pipelike structure approximately 1 km in diameter that extends from 1 to 6 km beneath sea level. This feature aligns axially with the bulk of seismicity and is interpreted as a highly fractured and altered zone encompassing a magma conduit. The velocity structure beneath the north flank of the volcano between depths of 1 and 6 km is characterized by large lateral velocity variations. High velocities within this region are interpreted as remnant dikes and sills and low velocities as regions along which magma migrates. No large low-velocity body suggestive of a magma chamber is resolved in the the upper 7-8 km of the crust.

  9. Glacier-volcano interactions in the north crater of Mt. Wrangell, Alaska

    USGS Publications Warehouse

    Abston, Carl; Motyka, Roman J.; McNutt, Stephen; Luthi, Martin; Truffer, Martin

    2007-01-01

    Glaciological and related observations from 1961 to 2005 at the summit of Mt Wrangell (62.008 N, 144.028W; 4317 m a.s.l.), a massive glacier-covered shield volcano in south-central Alaska, show marked changes that appear to have been initiated by the Great Alaska Earthquake (MW = 9.2) of 27 March 1964. The 4 x 6 km diameter, ice-filled Summit Caldera with several post-caldera craters on its rim, comprises the summit region where annual snow accumulation is 1–2 m of water equivalent and the mean annual temperature, measured 10 m below the snow surface, is –20°C. Precision surveying, aerial photogrammetry and measurements of temperature and snow accumulation were used to measure the loss of glacier ice equivalent to about 0.03 km3 of water from the North Crater in a decade. Glacier calorimetry was used to calculate the associated heat flux, which varied within the range 20–140W m–2; total heat flow was in the range 20–100 MW. Seismicity data from the crater’s rim show two distinct responses to large earthquakes at time scales from minutes to months. Chemistry of water and gas from fumaroles indicates a shallow magma heat source and seismicity data are consistent with this interpretation.

  10. Storage and interaction of compositionally heterogeneous magmas from the 1986 eruption of Augustine Volcano, Alaska

    USGS Publications Warehouse

    Roman, D.C.; Cashman, K.V.; Gardner, C.A.; Wallace, P.J.; Donovan, J.J.

    2006-01-01

    Compositional heterogeneity (56-64 wt% SiO2 whole-rock) in samples of tephra and lava from the 1986 eruption of Augustine Volcano, Alaska, raises questions about the physical nature of magma storage and interaction beneath this young and frequently active volcano. To determine conditions of magma storage and evolutionary histories of compositionally distinct magmas, we investigate physical and chemical characteristics of andesitic and dacitic magmas feeding the 1986 eruption. We calculate equilibrium temperatures and oxygen fugacities from Fe-Ti oxide compositions and find a continuous range in temperature from 877 to 947??C and high oxygen fugacities (??NNO=1-2) for all magmas. Melt inclusions in pyroxene phenocrysts analyzed by Fourier-transform infrared spectroscopy and electron probe microanalysis are dacitic to rhyolitic and have water contents ranging from <1 to ???7 wt%. Matrix glass compositions are rhyolitic and remarkably similar (???75.9-76.6 wt% SiO2) in all samples. All samples have ???25% phenocrysts, but lower-silica samples have much higher microlite contents than higher-silica samples. Continuous ranges in temperature and whole-rock composition, as well as linear trends in Harker diagrams and disequilibrium mineral textures, indicate that the 1986 magmas are the product of mixing between dacitic magma and a hotter, more mafic magma. The dacitic endmember is probably residual magma from the previous (1976) eruption of Augustine, and we interpret the mafic endmember to have been intruded from depth. Mixing appears to have continued as magmas ascended towards the vent. We suggest that the physical structure of the magma storage system beneath Augustine contributed to the sustained compositional heterogeneity of this eruption, which is best explained by magma storage and interaction in a vertically extensive system of interconnected dikes rather than a single coherent magma chamber and/or conduit. The typically short repose period (???10 years) between Augustine's recent eruptive pulses may also inhibit homogenization, as short repose periods and chemically heterogeneous magmas are observed at several volcanoes in the Cook Inlet region of Alaska. ?? Springer-Verlag 2005.

  11. Size- and Time-Resolved Composition of Volcanic Ash From Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Cahill, C. F.; Cahill, T. A.; Webley, P.; Wallace, K. L.; Dean, K. G.; Dehn, J.

    2006-12-01

    Augustine, an island volcano located approximately 275 km SSW of Anchorage, Alaska, produced thirteen discrete ash plumes during an explosive eruption phase that lasted from January 11 to January 28, 2006, followed by continuous ash emissions from January 29 to February 2. Immediately after the first two explosive eruptions on the morning of January 11, an eight-stage DRUM aerosol impactor was installed at Anchorage, Alaska, to collect size and time-resolved aerosols. On January 13th, the sampler was relocated, closer to the volcano, and installed at Homer, Alaska, a community approximately 110 km ENE of Augustine. At Homer, the sampler continuously collected aerosols in eight size fractions (35-5.0, 5.0-2.5, 2.5-1.15, 1.15-0.75, 0.75- 0.56, 0.56-0.34, 0.34-0.26 and 0.26-0.09 microns in aerodynamic diameter) between January 13 and February 11, 2006. The aerosols were analyzed with 3-hour resolution for mass using a beta-gauge, and for elemental composition (42 selected elements between sodium and lead) using synchrotron x-ray fluorescence. The aerosol time series at Homer shows that ash from Augustine impacted the site on numerous occasions during the eruption. The chemical composition and size distribution of the aerosols reaching Homer varied during the sampling period. The variations in the aerosol characteristics possibly reflect changes in the bulk chemistry of the erupting materials that are consistent with changes in coarse grained proximal tephra fall deposits. Volcanic ash plumes tracked using satellite data and the Puff ash dispersion model showed ash far beyond the neighborhood of the volcano. The trajectory models indicate and reports confirm that ash reached as far away as northern California. On January 31, during continuous ash emissions, the ash dispersion model forecast volcanic ash over Fairbanks, Alaska, a city located approximately 685 km NNE of Augustine. In response to the model's prediction, a three-stage DRUM aerosol impactor was deployed to collect aerosols in three size fractions (2.5-1.15, 1.15-0.34 and 0.34-0.10 microns in aerodynamic diameter) and samples of volcanic ash were collected. Corresponding satellite images did not show the presence of ash, however the lack of satellite detection is not surprising given the low concentrations of volcanic ash observed in Fairbanks. The silicon concentrations in the coarsest size fraction measured in Fairbanks (2.5-1.15 microns) were 1/80th of the concentrations observed in samples collected from the sampler in Homer. The combination of size- and time-resolved aerosol concentration and composition, satellite ash tracking and Puff dispersion modeling will provide scientists with a unique basis for determining the strengths and limitations of these techniques for characterizing and quantifying volcanic aerosols.

  12. Eruptive history and petrology of Mount Drum volcano, Wrangell Mountains, Alaska

    USGS Publications Warehouse

    Richter, D.H.; Moll-Stalcup, E. J.; Miller, T.P.; Lanphere, M.A.; Dalrymple, G.B.; Smith, R.L.

    1994-01-01

    Mount Drum is one of the youngest volcanoes in the subduction-related Wrangell volcanic field (80x200 km) of southcentral Alaska. It lies at the northwest end of a series of large, andesite-dominated shield volcanoes that show a northwesterly progression of age from 26 Ma near the Alaska-Yukon border to about 0.2 Ma at Mount Drum. The volcano was constructed between 750 and 250 ka during at least two cycles of cone building and ring-dome emplacement and was partially destroyed by violent explosive activity probably after 250 ka. Cone lavas range from basaltic andesite to dacite in composition; ring-domes are dacite to rhyolite. The last constructional activity occured in the vicinity of Snider Peak, on the south flank of the volcano, where extensive dacite flows and a dacite dome erupted at about 250 ka. The climactic explosive eruption, that destroyed the top and a part of the south flank of the volcano, produced more than 7 km3 of proximal hot and cold avalanche deposits and distal mudflows. The Mount Drum rocks have medium-K, calc-alkaline affinities and are generally plagioclase phyric. Silica contents range from 55.8 to 74.0 wt%, with a compositional gap between 66.8 and 72.8 wt%. All the rocks are enriched in alkali elements and depleted in Ta relative to the LREE, typical of volcanic arc rocks, but have higher MgO contents at a given SiO2, than typical orogenic medium-K andesites. Strontium-isotope ratios vary from 0.70292 to 0.70353. The compositional range of Mount Drum lavas is best explained by a combination of diverse parental magmas, magma mixing, and fractionation. The small, but significant, range in 87Sr/86Sr ratios in the basaltic andesites and the wide range of incompatible-element ratios exhibited by the basaltic andesites and andesites suggests the presence of compositionally diverse parent magmas. The lavas show abundant petrographic evidence of magma mixing, such as bimodal phenocryst size, resorbed phenocrysts, reaction rims, and disequilibrium mineral assemblages. In addition, some dacites and andesites contain Mg and Ni-rich olivines and/or have high MgO, Cr, Ni, Co, and Sc contents that are not in equilibrium with the host rock and indicate mixing between basalt or cumulate material and more evolved magmas. Incompatible element variations suggest that fractionation is responsible for some of the compositional range between basaltic andesite and dacite, but the rhyolites have K, Ba, Th, and Rb contents that are too low for the magmas to be generated by fractionation of the intermediate rocks. Limited Sr-isotope data support the possibility that the rhyolites may be partial melts of underlying volcanic rocks. ?? 1994 Springer-Verlag.

  13. Earthquake Triggering by Fluid Overpressure at Trident and Novarupta Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Prejean, S. G.; Thurber, C. H.; Murphy, R. A.; Pesicek, J. D.

    2011-12-01

    In 2008 the region of Trident and Novarupta volcanoes (TN) in the Katmai volcanic cluster, Alaska, experienced a swarm of small shallow earthquakes in association with a series of deep (>25 km) long-period (DLP) earthquakes. We captured the latter half of the swarm with a dense array of 10 temporary broadband seismometers deployed within the larger-scale permanent network of 20 stations. This level of seismic coverage is exceptional for a remote Alaskan volcano. We computed ~100 first motion fault plane solutions for brittle failure earthquakes in the Katmai region. Roughly 30% of the earthquakes located in the TN area have high quality P-wave polarities that are inconsistent with the best fitting double-couple fault plane solutions. We computed full moment tensors for a subset of these events following Julian and Foulger (Bull. Seis. Soc. Am., v.86, 972-980, 1996) based on P-wave amplitudes and P to SH amplitude ratios. Ray parameters and path-averaged Q corrections used in the inversions were derived from three dimensional velocity and attenuation models. Computed fault plane solutions in the TN region are highly diverse, unlike those of some neighboring Katmai area volcanoes. Results suggest that this area is a normal to strike-slip faulting environment where the vertical effective stress and most compressive horizontal effective stress were roughly equal in magnitude at the time of the swarm. Moment tensor results indicate that the majority of these earthquakes have positive isotropic components, indicative of volume increase, and CLVD components with major dipoles directed outward. These moment tensors are similar to those calculated at several geothermal areas globally and are consistent with simultaneous shear faulting and hydraulic fracturing, as water or gas rapidly intrudes into tensile cracks. Taken together, these observations suggest that earthquakes in the 2008 swarm occur on a complex network of normal and strike-slip faults in a high pore pressure volume of crust at roughly 4 km depth between the summit of Trident volcano and the Novarupta vent. Tomography results are generally consistent with this interpretation, as the earthquakes occur in a linear zone near a low velocity, high attenuation anomaly. High fault plane solution diversity in the swarm, moment tensor results, and the temporal association with DLP events suggest that the earthquakes were triggered by increased pore fluid pressure resulting from renewed fluid movement at depth.

  14. Investigating the pre- and post-eruptive stress regime at Redoubt volcano, Alaska, from 2008-1010 using seismic anisotropy and stress-tensor inversions

    NASA Astrophysics Data System (ADS)

    Gardine, M.; Roman, D. C.

    2010-12-01

    Redoubt volcano, located on the west side of Cook Inlet approximately 170 km southwest of Anchorage, Alaska, began erupting in March 2009. The eruption, which consisted of at least 17 explosive events over a three-week time period followed by three months of dome-building, significantly impacted both aviation and oil production operations in the area. Pre-eruptive seismicity was generally limited to deep (>20 km) long-period (DLP) earthquakes starting in late 2008, transitioning to bursts of strong, shallow volcanic tremor for nearly three months prior to the eruption. The near-complete absence of precursory volcano-tectonic (VT) earthquakes is unusual for eruptions of this type and complicates understanding of the dynamics of the Redoubt magmatic system. However, the strong volcanic tremor preceding the eruption suggests that magma was ascending and the system was pressurizing for months prior to the first explosion - a situation during which VT earthquakes typically occur. The study of subtle changes in stress conditions at Redoubt may elucidate the reasons for the observed near-complete lack of precursory VT seismicity. Using first-motion data from waveforms recorded by seismic stations operated in the vicinity of Redoubt by the Alaska Volcano Observatory (AVO) and the Alaska Earthquake Information Center (AEIC), we computed double-couple fault-plane solutions for approximately 200 VT earthquakes occurring in the months prior to and immediately following the first eruption in March 2009. The analysis of the fault-plane solutions using spatial and temporal stress-tensor inversions combined with cumulative misfit analysis will help to constrain if, when, and where localized precursory changes in stress occurred. In addition, we performed an analysis of shear-wave splitting using data from deep slab events located by AEIC within a 70 km radius for one year prior to and one year following the eruption, which resulted in approximately 500 high-quality measurements on the longest-running three-component station (REF). Initial results from this station show a fast-polarization azimuth (Φ ) towards the northeast during the months preceding the eruption. After the eruption, Φ is directed west-northwest, a direction more consistent with the regional stress direction. Shear-wave splitting analysis of data from additional Redoubt stations is expected to give further insight into the spatial pattern of local crustal stresses prior to the eruption.

  15. Tephra-Producing Eruptions of Holocene Age at Akutan Volcano, Alaska; Frequency, Magnitude, and Hazards

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Wallace, K. L.; Schwaiger, H.

    2012-12-01

    Akutan Volcano in the eastern Aleutian Islands of Alaska is one of the most historically active volcanoes in the Aleutian arc (43 eruptions in about the past 250 years). Explosive eruptions pose major hazards to aircraft flying north Pacific air routes and to local infrastructure on Akutan and neighboring Unalaska Island. Air travel, infrastructure, and population in the region have steadily increased during the past several decades, and thus it is important to better understand the frequency, magnitude, and characteristics of tephra-producing eruptions. The most recent eruption was a VEI 2 event on March 8-May 21, 1992 that resulted in minor ash emissions and trace amounts of proximal fallout. Nearly continuous low-level emission of ash and steam is typical of historical eruptions, and most of the historical events have been similar in magnitude to the 1992 event. The most recent major eruption occurred about 1600 yr. B.P. and likely produced the ca. 2-km diameter summit caldera and inundated valleys that head on the volcano with pyroclastic-flow and lahar deposits that are tens of meters thick. The 1600 yr. B.P. eruption covered most of Akutan Island with up to 2.5 m of coarse scoriaceous tephra fall, including deposits 0.5-1 m thick near the City of Akutan. Tephra-fall deposits associated with this eruption exhibit a continuous sequence of black, fine to coarse scoriaceous lapilli overlain by a lithic-rich facies and finally a muddy aggregate-rich facies indicating water involvement during the latter stages of the eruption. Other tephra deposits of Holocene age on Akutan Island include more than a dozen discrete fine to coarse ash beds and 3-6 beds of scoriaceous, coarse lapilli tephra indicating that there have been several additional major eruptions (>VEI 3) of Akutan Volcano during the Holocene. Radiocarbon dates on these events are pending. In addition to tephra falls from Akutan, other fine ash deposits are found on the island that originated from other Aleutian arc volcanoes. Tephra deposits from typical VEI 2 historical eruptions are not well preserved on the island so tephra-fall frequency estimated from stratigraphic studies is underestimated. Akutan Island is home to the largest seafood processing plant in North America and has a workforce of more than one thousand people. Other infrastructure consists of a recently constructed paved airfield on neighboring Akun Island (25 km east of the active vent) and a new boat harbor at the head of Akutan Harbor. Plans to develop greenhouses, tourism, and increased cold storage capacity on Akutan and Akun Islands also are evolving. To support the power demands of the development efforts, The City of Akutan is considering the utilization of geothermal resources on the island that are located in Hot Springs Bay valley northwest of the city. All of the existing and planned infrastructure, water supply, and residential areas are about 12 km downwind (east) of the volcano and are at risk from ash-producing eruptions. The historical eruptive history suggests that VEI 2 eruptions are plausible in the near future and the Holocene tephra-fall record indicates that large eruptions (VEI 4 or larger) occur about every few thousand years. Numerical modeling of tephra fallout based on the record of ash-producing eruptions will be used to improve tephra-fall hazard assessments for the area.

  16. Paleozoic and Paleoproterozoic Zircon in Igneous Xenoliths Assimilated at Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Bacon, C. R.; Vazquez, J. A.; Wooden, J. L.

    2010-12-01

    Historically active Redoubt Volcano is a basalt-to-dacite cone constructed upon the Jurassic-early Tertiary Alaska-Aleutian Range batholith. New SHRIMP-RG U-Pb age and trace-element concentration results for zircons from gabbroic xenoliths and crystal-rich andesitic mush from a late Pleistocene pyroclastic deposit indicate that ~310 Ma and ~1865 Ma igneous rocks underlie Redoubt at depth. Two gabbros have sharply terminated prismatic zircons that yield ages of ~310 Ma. Zircons from a crystal mush sample are overwhelmingly ~1865 Ma and appear rounded due to incomplete dissolution. Binary plots of element concentrations or ratios show clustering of data for ~310-Ma grains and markedly coherent trends for ~1865-Ma grains; e.g., ~310-Ma grains have higher Eu/Eu* than most of the ~1865-Ma grains, the majority of which form a narrow band of decreasing Eu/Eu* with increasing Hf content which suggests that ~1865-Ma zircons come from igneous source rocks. It is very unlikely that detrital zircons from a metasedimentary rock would have this level of homogeneity in age and composition. One gabbro contains abundant ~1865 Ma igneous zircons, ~300-310 Ma fluid-precipitated zircons characterized by very low U and Th concentrations and Th/U ratios, and uncommon ~100 Ma zircons. We propose that (1) ~310 Ma gabbro xenoliths from Redoubt Volcano belong to the same family of plutons dated by Aleinikoff et al. (USGS Circular 1016, 1988) and Gardner et al. (Geology, 1988) located ≥500 km to the northeast in basement rocks of the Wrangellia and Alexander terranes and (2) ~1865 Ma zircons are inherited from igneous rock, potentially from a continental fragment that possibly correlates with the Fort Simpson terrane or Great Bear magmatic zone of the Wopmay Orogen of northwestern Laurentia. Possibly, elements of these Paleoproterozoic terranes intersected the Paleozoic North American continental margin where they may have formed a component of the basement to the Wrangellia-Alexander-Peninsular composite terrane prior to transport to its present location (e.g., Colpron and Nelson, Geological Society, London, Special Publication 318, 2009). Xenocrysts from the ~1865 Ma igneous rocks, and possibly also ~310 Ma gabbros, are contained in relatively low-temperature mush and partially melted gabbro that we interpret to have been derived from the margin of the subvolcanic magma accumulation and storage region defined by seismicity at 4-10 km bsl. The Redoubt crystal mush contains evidence for assimilation of ~1865 Ma igneous rocks that have no equivalent exposed in Alaska. The discovery of Paleoproterozoic grains as the dominant zircon component in crystal mush raises the question of the origin of other crystals in Redoubt magmas.

  17. ASTER Urgent Response to the 2006 Eruption of Augustine Volcano, Alaska: Science and Decision Support Gained From Frequent High-resolution, Satellite Thermal Infrared Imaging of Volcanic Events

    NASA Astrophysics Data System (ADS)

    Wessels, R. L.; Ramsey, M. S.; Schneider, D. S.; Coombs, M.; Dehn, J.; Realmuto, V. J.

    2006-12-01

    Augustine Volcano, Alaska explosively erupted on January 11, 2006 after nearly eight months of increasing seismicity, deformation, gas emission, and small phreatic explosions. The volcano produced a total of 13 explosive eruptions during the last three weeks of January 2006. A new summit lava dome and two short, blocky lava flows grew during February and March 2006. A series of 7 daytime and 15 nighttime Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scenes were acquired in response to this new activity. This response was facilitated by a new ASTER Urgent Request Protocol system. The ASTER data provided several significant observations as a part of a much larger suite of real-time or near-real-time data from other satellite (AVHRR, MODIS), airborne (FLIR, visual, gas), and ground-based (seismometers, radiometers) sensors used at the Alaska Volcano Observatory (AVO). ASTER is well-suited to volcanic observations because of its 15-m to 90-m spatial resolution, its ability to be scheduled and point off-nadir, and its ability to collect visible-near infrared (VNIR) to thermal infrared (TIR) data during both the day and night. Aided by the volcano's high latitude (59.4°N) ASTER was able to provide frequent repeat imaging as short as one day between scenes with an average 6-day repeat during the height of activity. These data provided a time series of high-resolution VNIR, shortwave infrared (SWIR - detects temperatures from about 200°C to > 600°C averaged over a 30-m pixel), and TIR (detects temperatures up to about 100°C averaged over a 90-m pixel) data of the volcano and its eruptive products. Frequent satellite imaging of volcanoes is necessary to record rapid changes in activity and to avoid recurring cloud cover. Of the 22 ASTER scenes acquired between October 30, 2005 and May 30, 2006, the volcano was clear to partly cloudy in 13 scenes. The most useful pre-eruption ASTER Urgent Request image was acquired on December 20. These data showed a broad area of slightly elevated TIR radiances that correlated with new snow-free areas and fumaroles at the summit. Thin cirrus cloud cover prevented quantitative TIR temperature extraction. During the night of February 1, 2006, ASTER imaged an ash-rich plume and fresh pyroclastic-flow deposits near the end of a 6-day continuous phase of the eruption. A decorrelation stretch of ASTER TIR bands 14, 13, and 11 suggests that the eruption plume was a mixture of ash and SO2. The 90-m TIR sensor was able to detect subtle surface radiance differences between the cooler distal ends of the pyroclastic-flow deposits and the warmer proximal areas. These temperature differences were controlled by both the age (hours) and thickness of the deposits. The SWIR data show a region of ~ 700 m x 300 m of hot pixels centered at the summit dome with a maximum brightness temperature of 619°C. ASTER data spanning February 22 through March 14 documented the continued growth of the summit domes and lava flows and gradual cooling of the block and ash deposits.

  18. Volcanoes

    MedlinePlus

    ... or Traumatic Event Resources for Families Resources for Leaders Resources for State and Local Governments Emergency Responders: ... Facebook Tweet Share Compartir Volcanoes can produce ash, toxic gases, flashfloods of hot water and debris called ...

  19. Volcanoes

    USGS Publications Warehouse

    Tilling, Robert I.

    1998-01-01

    Volcanoes destroy and volcanoes create. The catastrophic eruption of Mount St. Helens on May 18, 1980, made clear the awesome destructive power of a volcano. Yet, over a time span longer than human memory and record, volcanoes have played a key role in forming and modifying the planet upon which we live. More than 80 percent of the Earth's surface--above and below sea level--is of volcanic origin. Gaseous emissions from volcanic vents over hundreds of millions of years formed the Earth's earliest oceans and atmosphere, which supplied the ingredients vital to evolve and sustain life. Over geologic eons, countless volcanic eruptions have produced mountains, plateaus, and plains, which subsequent erosion and weathering have sculpted into majestic landscapes and formed fertile soils.

  20. Relative velocity changes using ambient seismic noise at Okmok and Redoubt volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Bennington, N. L.; Haney, M. M.; De Angelis, S.; Thurber, C. H.

    2013-12-01

    Okmok and Redoubt are two of the most active volcanoes in the Aleutian Arc. Leading up to its most recent eruption, Okmok, a shield volcano on Umnak Island, showed precursors to volcanic activity only five hours before it erupted explosively in July 2008. Redoubt, a stratovolcano located along the Cook Inlet, displayed several months of precursory activity leading up to its March 2009 eruption. Frequent activity at both volcanoes poses a major hazard due to heavy traffic along the North Pacific air routes. Additionally, Okmok is adjacent to several of the world's most productive fisheries and Redoubt is located only 110 miles SW of Anchorage, the major population center of Alaska. For these reasons, it is imperative that we improve our ability to detect early signs of unrest, which could potentially lead to eruptive activity at these volcanoes. We take advantage of continuous waveforms recorded on seismic networks at Redoubt and Okmok in an attempt to identify seismic precursors to the recent eruptions at both volcanoes. We perform seismic interferometry using ambient noise, following Brenguier et al. (2008), in order to probe the subsurface and determine temporal changes in relative seismic velocity from pre- through post-eruption, for the 2008 Okmok and 2009 Redoubt eruptions. In a preliminary investigation, we analyzed 6 months of noise cross-correlation functions averaged over 10-day intervals leading up to the 2009 eruption at Redoubt. During February 2009, station pairs RSO-DFR and RDN-RSO showed a decrease in seismic velocity of ~0.02%. By the beginning of March, the relative velocity changes returned to background levels. Stations RSO and RDN are located within the summit breach, and station DFR is to the north. Although these results are preliminary, it is interesting to note that the decrease in seismic velocity at both station pairs overlaps with the time period when Grapenthin et al. (2012) hypothesize magma in the mid-to-deep crustal reservoir was reheated and migrated to a second shallow reservoir between 2 and 4.5 km depth. This hypothesized shallow magma reservoir is within the sensitivity depth of our ambient noise analysis, and thus the decrease in seismic velocity may be associated with magma movement at shallow depths underneath Redoubt. At the onset of eruption, the relative velocity change at station pair RDN-RSO decreased by ~0.03% while that at RSO-DFR remained at background levels. Notably, this decrease in seismic velocity is observed only at the station pair with a propagation path that traverses the summit breach. Our investigation continues as we search for time variations in the ambient seismic noise signal preceding and following the 2008 Okmok and 2009 Redoubt eruptions and endeavor to identify what those changes may represent.

  1. Permafrost Observatory near Gakona, Alaska. Local-Scale Features in Permafrost Distribution and Temperatures.

    NASA Astrophysics Data System (ADS)

    Romanovsky, V.; Yoshikawa, K.; Sergueev, D.; Shur, Y.

    2005-12-01

    During the summer of 2004, the Geophysical Institute University of Alaska Fairbanks (GI UAF) established the Gakona Permafrost Observatory. This project is funded by the Office of Naval Research and the National Science Foundation. The Observatory is located in a large intermountain depression in the Copper River Basin. Permafrost in this area is widespread, in spite of its location near the southern boundary of the discontinuous permafrost zone. Together with the recently established Barrow Permafrost Observatory and with other GI UAF Permafrost Observatories, the Gakona Observatory will provide critically needed information on the permafrost response to recent and projected climate warming. The positioning of this observatory near the southern limits of permafrost distribution in Alaska makes this location very advantageous. With the growing possibility of near-future climate warming, permafrost integrity at this location will be affected first and will show significant changes in the very near future. In fact, at some locations within the area of observations permafrost already started to degrade and closed and, possibly, open taliks have been formed. Mean annual air temperature in this area was increasing from -3.5 C in the early 1950s to -1.6 C in the early 2000s. Several 10 m deep boreholes within the area with natural and disturbed surface conditions were equipped with thermistor strings and loggers to automatically monitor ground temperature dynamics with one-hour time resolution. Air temperature, snow depth, and soil liquid water content at four different depths together with 30 m deep temperature profile are also measured hourly at one location in the black spruce forest. The temperature data obtained in the first year of the project at this location show that permafrost temperature within the depth interval between 3 and 30 meters is practically constant at -0.6 C during the entire year. Obtained data also show that the partial thaw of permafrost from the top down is already underway and tightly relates to distinguish surface micro-topographical features. These features are elongated depressions (0.5 to 1.5 m deep and 10 to 100 m wide) with no trees and no moss on the ground surface. The depth to the permafrost table within these depressions are different at different locations and vary between 2 and 8 meters according to a survey by Duane Miller & Associates and to our temperature measurements in several boreholes. Repeated measurements of the permafrost table location within one of these depressions show increase in depth from approximately 3.5 m in 1989 to 5 m in 2004. As part of our initial survey, we applied geophysical methods (DC Resistivity and Ground Penetrating Radar) to investigate permafrost distribution in vertical and horizontal directions within the research area. Results obtained using DC Resistivity survey (Syscal Pro R1 switch 72 channel resistivity system) show that permafrost in the forest is stable and contain a limited amount of unfrozen water (resistivity is 600 ohm-m and higher, up to 1800 ohm-m). The lower boundary of permafrost locates at the depth of 50 to 60 meters. A talik (possibly open) was discovered under one of the mentioned above elongated depressions. The lateral extent of this talik is only 10 meters at the surface increasing with depth to several tens of meters.

  2. The unusual mineralogy of the Hayes River rhyolite, Hayes Volcano, Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Hayden, L. A.; Coombs, M. L.; McHugh, K.

    2013-12-01

    Hayes Volcano is an ice-covered volcanic massif located in the northern Cook Inlet region approximately 135 miles northwest of Anchorage, Alaska. The last major eruptive episode of Hayes, and the only known in any detail, occurred ~3,700 yr B.P. and produced the Hayes Tephra Set H, a series of dacitic fall deposits widespread throughout southcentral Alaska (Riehle et al., 1994, Quat. Res. 33, p. 91-108). An undated, early Holocene pyroclastic-flow deposit exposed beneath Tephra Set H in the Hayes River valley is unusual in the Aleutian-Alaska subduction zone in whole-rock composition and mineralogy. The deposit comprises rhyolite pumice (~75 wt% SiO2) that contain phenocrysts of plagioclase, sanidine, quartz, and biotite in vesicular, clear matrix glass, and <1% dense, white cognate inclusions with the same whole-rock composition and phenocryst assemblage as the pumice, but a crystalline matrix. Holocrystalline inclusions may represent portions of the magma body that rapidly quenched in the shallow subsurface as dikes or chamber rinds and were then excavated during explosive eruption. Rhyolite and inclusions are peraluminous (2-3 % normative corundum), high-K, enriched in incompatible elements, and depleted in Sr and Eu. In accord with its evolved and enriched composition the rhyolite pumice and inclusions contain an abundance of accessory phases, including apatite, monazite, xenotime, and zircon. Monazite are euhedral, as large as 500 um, ThO2-rich (up to 4 wt%) and contain significant amounts of Ag (200-500 ppm). Xenotime are generally smaller than the monazite and occur frequently as small blebs. Rhyolite pumices also contain Fe-sulfides, Cu, Sn, Ni, and barite. Sanidine phenocrysts in the pumice and inclusions are sharply zoned and highly enriched in the celsian component (up to 5 wt% BaO) and also show LREE enrichment. Inclusions contain abundant Mn-rich cordierite (~3 wt% Mn2O3) in the san-plag-qtz matrix, as well as Fe-Ti oxides that are relatively high in Mn2O3 (>1 wt%) and REE-enriched. Zircon saturation temperatures (716 C) and two-feldspar thermometry (630-700 C for phenocryst rims; 660 C for inclusion matrix microphenocrysts) suggest a cool magma that must have been volatile-rich given its relatively low phenocryst content (~25 %). A lack of crustal xenocrysts, and Pb, Sr, and Nd isotopes similar to other Cook Inlet volcanoes (McHugh et al., 2012 Fall AGU, V31A-2760) suggest that the rhyolite is not a crustal melt, and we suggest that it formed by low degrees of melting or high degree of crystallization of mafic arc-related rocks. At Hayes, concentrations of REE and metals resulted from extreme fractionation process(es), which active over extended time period may lead to the formation of mineral deposits.

  3. Seismic and Gas Analyses Imply Magmatic Intrusion at Iliamna Volcano, Alaska in 2012

    NASA Astrophysics Data System (ADS)

    Prejean, S. G.; Werner, C. A.; Buurman, H.; Doukas, M. P.; Kelly, P. J.; Kern, C.; Ketner, D.; Stihler, S.; Thurber, C. H.; West, M. E.

    2012-12-01

    In early 2012, Iliamna Volcano, an ice-covered andesitic stratovolcano located in the Cook Inlet region of Alaska, had a vigorous earthquake swarm that included both brittle-failure earthquakes (M<=3.0) and smaller repeating low-frequency events. The swarm peaked in late February and early March with a maximum rate of roughly 1 event per minute. Initial earthquake locations were poor, as the normally sparse network (6 stations) was further compromised by outages. In an attempt to improve earthquake locations we linked differential travel times from this swarm to previous high-quality earthquake relocations (Statz-Boyer, et al., 2009, J. Volc. Geotherm. Res., v. 184, p. 323-332) using TomoDD. This analysis can be done quickly during unrest episodes if the optimal parameterization for the inversion and differential travel times for historical earthquakes have been determined previously. Relocated hypocenters shifted significantly westward from initial catalog locations, aligning on a ~N-S trending structure south of the volcano's edifice at 0-4 km depth. This crustal volume has otherwise been seismically quiet except during a possible magmatic intrusion at Iliamna in 1996, when it sustained a similar swarm (Roman et al., 2004, J. Volc. Geotherm. Res., v. 130, p. 265-284). Analysis of the relative amplitudes between the small low-frequency and located brittle failure events indicates that their sources are geographically separate, with the low-frequency events sourced closer to the fumarolically active summit region, ~4 km north of the brittle failure events. Airborne gas-emission measurements on March 17 revealed emission rates of up to 2000 and 580 tonnes per day (t/d) of CO2 and SO2, respectively, and a molar C/S ratio of 5. Visual observations from the flight revealed unusually vigorous fumarole activity near the summit. Subsequent measurements on June 20 and 22 showed continued high emissions of up to 1190 and 440 t/d of CO2 and SO2, respectively, with a C/S ratio of 4. These emission measurements are similar to those measured during the height of the 1996 unrest episode and are significantly above background measurements between 1998 and August 2011, which were typically below 100 and 60 t/d of CO2 and SO2. Taken together, gas and seismic data suggest that the earthquake swarm was driven by magmatic intrusion. Gas flux rates are consistent with those measured for degassing andesitic magmas in the shallow crust at other Cook Inlet volcanoes. Increased heat and degassing likely caused small low-frequency events in the shallow hydrothermal system near the volcano's summit, and/or may have destabilized the glacier, triggering shallow low-frequency glacial events. This unrest episode demonstrates how magmatic intrusions can cause spatially disparate earthquake swarms in hydrothermal systems and on pre-existing crustal structures.

  4. Preeruptive inflation and surface interferometric coherence characteristics revealed by satellite radar interferometry at Makushin Volcano, Alaska: 1993-2000

    USGS Publications Warehouse

    Lu, Zhiming; Power, J.A.; McConnell, V.S.; Wicks, C., Jr.; Dzurisin, D.

    2002-01-01

    Pilot reports in January 1995 and geologic field observations from the summer of 1996 indicate that a relatively small explosive eruption of Makushin, one of the more frequently active volcanoes in the Aleutian arc of Alaska, occured on 30 January 1995. Several independent radar interferograms that each span the time period from October 1993 to September 1995 show evidence of ???7 cm of uplift centered on the volcano's east flank, which we interpret as preeruptive inflation of a ???7-km-deep magma source (??V = 0.022 km3). Subsequent interferograms for 1995-2000, a period that included no reported eruptive activity, show no evidence of additional ground deformation. Interferometric coherence at C band is found to persist for 3 years or more on lava flow and other rocky surfaces covered with short grass and sparsely distributed tall grass and for at least 1 year on most pyroclastic deposits. On lava flow and rocky surfaces with dense tall grass and on alluvium, coherence lasts for a few months. Snow and ice surfaces lose coherence within a few days. This extended timeframe of coherence over a variety of surface materials makes C band radar interferometry an effective tool for studying volcano deformation in Alaska and other similar high-latitude regions.

  5. Investigation of volcanic processes using seismology and geodesy at Okmok Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Ohlendorf, Summer Joi

    Okmok Volcano, Alaska is a frequently active system with eruptions in 1997 and 2008 that differed in style and vent location. We conduct various seismic and geodetic studies of Okmok, focusing on better characterizing the volcano's subsurface structure and changes leading up to the 2008 eruption. In the first study, we perform ambient noise interferometry using cross-correlation of noise between station pairs to investigate changes in Okmok's seismic properties preceding and following the 2008 eruption. In the second, we test the influence of phase-weighted versus linear stacking on the quality of ambient noise tomography (ANT). In the third, we perform a joint inversion of body-wave arrivals and surface wave dispersion to solve for three-dimensional P-wave and S-wave velocity structure and hypocenter locations. Finally, we conduct time series analysis with temporal adjustment of Okmok's deformation between 1997 and 2008 using wrapped phase observations from interferometric synthetic aperture radar (InSAR). We find two prominent signals in relative seismic velocity in the intereruptive period, strongest on station pairs with paths beneath the caldera. These are a seasonal variation, believed to be due to precipitation and snow loading, overprinted by a gradual increase in velocity until the 2008 eruption. The increase, contrary to typical observations preceding eruptions, may be due to viscoelastic effects decreasing the stresses above the pressurized magma chamber during the late intereruptive period. We find that phase-weighted stacking improves the signal-to-noise ratio of Green's functions and the quality of dispersion curves, group velocity maps, and the resulting S velocity model with respect to linearly stacking. The ANT-derived S model shows two major low velocity zones (LVZs) at depths that agree with previous studies, but their lateral extent is unrealistically large. Joint inversion of body-wave and surface-wave data produces an optimal P model similar to the body-wave-only model, but the S model improves noticeably and suggests slightly greater depth extent of the lower LVZ. From temporal adjustment on InSAR-estimated variations in source strength, we find an adequate fit to a parameterization consisting of twoexponential decay steps, suggesting that viscoelastic processes play a role in deformation during intereruptive periods.

  6. Geodetic Measurements and Mechanical Models of Cyclic Deformation at Okmok Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Feigl, K.; Masterlark, T.; Lu, Z.; Ohlendorf, S. J.; Thurber, C. H.; Sigmundsson, F.

    2009-12-01

    The 1997 and 2008 eruptions of Okmok volcano, Alaska, provide a rare opportunity for conducting a rheological experiment to unravel the complex processes associated with magma migration, storage, and eruption in an active volcano. In this experiment, the magma flux during the eruption provides the “impulse” and the subsequent, transient deformation, the “response”. By simulating the impulse, measuring the response, and interpreting the constitutive relations between the two, one can infer the rheology. Okmok is an excellent natural laboratory for such an experiment because a complete cycle of deformation has been monitored using geodetic and seismic means, including: (a) geodetic time series from Interferometric Synthetic Aperture Radar (InSAR) and the Global Positioning System (GPS), (b) earthquake locations; and (c) seismic tomography. We are developing quantitative models using the Finite Element Method (FEM) to simulate the timing and location of the observed seismicity and deformation by accounting for: (a) the geometry and loading of the magma chamber and lava flow, (b) the spatial distribution of material properties; and (c) the constitutive (rheological) relations between stress and strain. Here, we test the hypothesis that the deformation following the 1997 eruption did not reach a steady state before the eruption in 2008. To do so, we iteratively confront the FEM models with the InSAR measurements using the General Inversion of Phase Technique (GIPhT). This approach models the InSAR phase data directly, without unwrapping, as developed, validated, and applied by Feigl and Thurber [Geophys. J. Int., 2009]. By minimizing a cost function that quantifies the misfit between observed and modeled values in terms of “wrapped” phase (with values ranging from -1/2 to +1/2 cycles), GIPhT can estimate parameters in a geophysical model. By avoiding the pitfalls of phase-unwrapping approaches, GIPhT allows the analysis, interpretation and modeling of more interferometric pairs than approaches that require unwrapping. GIPhT also allows statistical testing of hypotheses because the wrapped phase residuals follow a Von Mises distribution. As a result, the model parameters estimated by GIPhT include formal uncertainties.

  7. Double-difference relocation of earthquakes at Uturuncu volcano, Bolivia, and Interior Alaska

    NASA Astrophysics Data System (ADS)

    Hutchinson, Laura

    In order to reliably interpret seismic patterns, we must have reliable earthquake locations. To improve our catalog locations, I incorporate cross-correlations into double-difference earthquake relocations to generate high precision relative locations. I perform relocations for two regions, one volcanic and one tectonic. At Uturuncu volcano, I incorporate a wealth of previous studies to present a picture of the processes at play. Seismic, gravity, InSAR, and electromagnetic studies all show that there is a magma body underlying the entire region, and chemical studies suggest that this magma body (the Altiplano-Puna Magma Body, or APMB) is the source of the large ignimbrite eruptions that have occurred in the past. The recent uplift has been modeled as a new batch of magma rising off the APMB, beginning the ascent as a diapir. My relocation results indicate that the seismicity aligns with the top of one of the imaged low velocities zones, which I interpret as a diapir beneath Uturuncu. The earthquakes mark the depth at which the crust is cool enough for brittle deformation. I also perform cross-correlations to determine families of similar events. These families are located around the summit of Uturuncu and display a radial pattern. This suggests that they are due to local volcanic stresses, such as inflation of the volcano, rather than regional stresses. In Interior Alaska, I study a region that is very seismically active, yet has no mapped Holocene faults. There are a series of seismic zones in the area, each comprised of NNE-striking seismic lineations. I perform earthquake relocations on 40 years worth of seismicity in order to refine and interpret fault planes. I additionally examine three earthquake sequences in the Minto Flats Seismic Zone (MFSZ). These earthquakes are large enough (≥M5) to produce an aftershock sequence to map out the rupture plane. I find that two of the three earthquakes occurred on WNW-striking planes, roughly perpendicular to the dominant direction of the seismic zone. The third earthquake ruptured along a NNE-striking plane but generated a WNW-ESE halo of aftershocks, suggesting that the basement is highly fractured in the region. The NW pattern that I find for the three sequences falls in line with my findings for the rest of the Interior: there are a series of NE-striking faults that are cut by NW-striking faults. Throughout the Interior, these faults cross at approximately 60°, suggesting that they are conjugate faults. I believe that the three earthquake sequences in the MFSZ are also conjugate faults and are a part of the broader conjugate system throughout the Interior.

  8. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Though it's not quite spring, waters in the Gulf of Alaska (right) appear to be blooming with plant life in this true-color MODIS image from March 4, 2002. East of the Alaska Peninsula (bottom center), blue-green swirls surround Kodiak Island. These colors are the result of light reflecting off chlorophyll and other pigments in tiny marine plants called phytoplankton. The bloom extends southward and clear dividing line can be seen west to east, where the bloom disappears over the deeper waters of the Aleutian Trench. North in Cook Inlet, large amounts of red clay sediment are turning the water brown. To the east, more colorful swirls stretch out from Prince William Sound, and may be a mixture of clay sediment from the Copper River and phytoplankton. Arcing across the top left of the image, the snow-covered Brooks Range towers over Alaska's North Slope. Frozen rivers trace white ribbons across the winter landscape. The mighty Yukon River traverses the entire state, beginning at the right edge of the image (a little way down from the top) running all the way over to the Bering Sea, still locked in ice. In the high-resolution image, the circular, snow-filled calderas of two volcanoes are apparent along the Alaska Peninsula. In Bristol Bay (to the west of the Peninsula) and in a couple of the semi-clear areas in the Bering Sea, it appears that there may be an ice algae bloom along the sharp ice edge (see high resolution image for better details). Ground-based observations from the area have revealed that an under-ice bloom often starts as early as February in this region and then seeds the more typical spring bloom later in the season.

  9. Ground deformation associated with the March 1996 earthquake swarm at Akutan volcano, Alaska, revealed by satellite radar interferometry

    USGS Publications Warehouse

    Lu, Zhiming; Wicks, C., Jr.; Power, J.A.; Dzurisin, D.

    2000-01-01

    In March 1996 an intense swarm of volcano-tectonic earthquakes (???3000 felt by local residents, Mmax = 5.1, cumulative moment of 2.7 ??1018 N m) beneath Akutan Island in the Aleutian volcanic arc, Alaska, produced extensive ground cracks but no eruption of Akutan volcano. Synthetic aperture radar interferograms that span the time of the swarm reveal complex island-wide deformation: the western part of the island including Akutan volcano moved upward, while the eastern part moved downward. The axis of the deformation approximately aligns with new ground cracks on the western part of the island and with Holocene normal faults that were reactivated during the swarm on the eastern part of the island. The axis is also roughly parallel to the direction of greatest compressional stress in the region. No ground movements greater than 2.83 cm were observed outside the volcano's summit caldera for periods of 4 years before or 2 years after the swarm. We modeled the deformation primarily as the emplacement of a shallow, east-west trending, north dipping dike plus inflation of a deep, Mogi-type magma body beneath the volcano. The pattern of subsidence on the eastern part of the island is poorly constrained. It might have been produced by extensional tectonic strain that both reactivated preexisting faults on the eastern part of the island and facilitated magma movement beneath the western part. Alternatively, magma intrusion beneath the volcano might have been the cause of extension and subsidence in the eastern part of the island. We attribute localized subsidence in an area of active fumaroles within the Akutan caldera, by as much as 10 cm during 1992-1993 and 1996-1998, to fluid withdrawal or depressurization of the shallow hydrothermal system. Copyright 2000 by the American Geophysical Union.

  10. Observations of the Electrical Activity of the Redoubt Volcano in Alaska

    NASA Astrophysics Data System (ADS)

    Krehbiel, P. R.; Behnke, S. A.; Thomas, R. J.; Edens, H. E.; Rison, W.; McNutt, S. R.; Higman, B.; Holzworth, R. H.; Thomas, J. N.

    2009-12-01

    The Mt. Redoubt volcano in Alaska underwent a series of 22 major explosive eruptions over a 2.5 week period between 23 March and 4 April 2009. We were able to deploy a 4-station Lightning Mapping Array (LMA) in advance of the eruptions along a 60 km stretch of the Kenai coastline, 70-80 km east of Redoubt on the opposite side of Cook Inlet, and to monitor and control the station operations remotely via internet connections. The LMA data show that the eruptions produced spectacular lightning, both over and downwind of the volcano, lasting between 20 to 80 minutes depending on the eruption strength. The discharging was essentially continuous during the initial stages of the eruptions and gradually evolved into more discrete and spatially structured discharges displaced from 10 km up to 80 or 90 km away from Redoubt. The discharge rates and VHF radiation signals were comparable to or greater than observed in Great Plains thunderstorms, with discernible but complex 'flashes' occurring at a rate of 2-3 per second in the active stages of eruptions, decaying to about 10-15 per minute of horizontally extensive discrete discharges in later stages. Individual eruptions produced literally thousands of discharges. The approximately linear array of the mapping stations, coupled with their distance from Redoubt and the inability to have a station at a closer distance, has precluded obtaining useful altitude information from the time-of-arrival data. The exception has been lightning at the end of the March 28 eruption as the plume cloud drifted over the northern end of the LMA network; which showed negative charge at 6 km altitude and positive charge between 8 and 9 km altitude, exactly the same as seen in normally electrified thunderstorms. Three of the four stations had been deployed on 50-100m high bluffs overlooking Cook Inlet in an attempt to use sea-surface interference effects to determine altitude, as in our study of the 2006 Augustine eruptions. But only partial interference fringes are seen in the data making them more difficult to interpret and unlikely to provide additional information on the vertical charge structure of the clouds. By virtue of having prolific negative leader activity, the clouds clearly contained substantial amounts of net positive charge. Finally, cloud-to-ground and possibly some intracloud lightning associated with the Redoubt eruptions was detected by the Alaska BLM network, which located 518 strikes during the two week long eruption period. The World Wide Lightning Location Network (WWLLN) located 486 strikes during the same period. Most of the eruptions occurred during overcast or stormy weather conditions and were not seen visually, but during three eruptions the weather was clear enough for the lightning to be visually observed and also captured on photos and video. Distant video photographs of the lightning show the occurrence of both upward and downward branched channels below cloud base and are being analyzed to retrieve height information.

  11. Modeling and forecasting tephra hazards at Redoubt Volcano, Alaska, during 2009 unrest and eruption

    NASA Astrophysics Data System (ADS)

    Mastin, L. G.; Denlinger, R. P.; Wallace, K. L.; Schaefer, J. R.

    2009-12-01

    In late 2008, Redoubt Volcano, on the west coast of Alaskas Cook Inlet, began a period of unrest that culminated in more than 19 small tephra-producing events between March 19 and April 4, 2009, followed by growth of a lava dome whose volume now exceeds 70 million cubic meters. The explosive events lasted from <1 to 31 minutes, sent tephra columns to heights of 19 km asl, and emitted dense-rock (DRE) tephra volumes up to several million cubic meters. Tephra fall affected transportation and infrastructure throughout Cook Inlet, including the Anchorage metropolitan area. The months of unrest that preceded the first explosive event allowed us to develop tools to forecast tephra hazards. As described in an accompanying abstract, colleagues at the University of Pisa produced automated, daily tephra-fall forecast maps using the 3-D VOL-CALPUFF model with input scenarios that represented likely event sizes and durations. Tephra-fall forecast maps were also generated every six hours for hypothetical events of 10M m3 volume DRE using the 2-D model ASHFALL, and relationships between hypothetical plume height and eruption rate were evaluated four times daily under then-current atmospheric conditions using the program PLUMERIA. Eruptive deposits were mapped and isomass contours constructed for the two largest events, March 24 (0340-0355Z) and April 4 (1358-1429Z), which produced radar-determined plume heights of 18.3 and 15.2 km asl (~15.6 and 12.5 km above the vent), and tephra volumes (DRE) of 6.3M and 3.1M m3, respectively. For the volumetric eruption rates calculated from mapped erupted volume and seismic duration (V=6.2103 and 1.7103 m3/s DRE), measured plume heights H above the vent fall within 10% of the empirical best-fit curve H=1.67V0.259 published in the book Volcanic Plumes by Sparks et al. (1997, eq. 5.1). The plume heights are slightly higher than (but still within 13% of) the 14.6 and 11.1 km predicted by PLUMERIA under the existing atmospheric conditions. We have also modeled these two events using the 3-D transient model FALL3D, which considers topographic effects on wind and tephra dispersal. Using the eruption rates and plume heights constrained by deposit mapping, seismic data, and Doppler radar, and an archived wind field obtained from the NOAA GDAS model for these dates, modeled isomass contours from the April 4 event closely resemble measured values, but modeled contours from the March 24 event extend only about half to three fourths as far from the volcano as measured. This discrepancy may result from inaccuracies in the modeled wind pattern, the grain-size distribution, or turbulent entrainment algorithms. The deposit pattern may also have been affected by a lateral blast which is thought to have accompanied this event.

  12. The 1989 1990 eruption of Redoubt Volcano, Alaska: impacts on aircraft operations

    NASA Astrophysics Data System (ADS)

    Casadevall, Thomas J.

    1994-08-01

    The December 1989-June 1990 eruption of Redoubt Volcano affected commercial and military air operations in the vicinity of Anchorage, Alaska. These effects were due to the direct impact of volcanic ash on jet aircraft, as well as to the rerouting and cancellations of flight operations owing to eruptive activity. Between December and February, five commercial jetliners were damaged from ash encounters. The most serious incident took place on December 15, 1989 when a Boeing 747-400 aircraft temporarily lost power of all four engines after encountering an ash cloud as the airplane descended for a landing in Anchorage. While there were no injuries to passengers, the damage to engines, avionics, and aircraft structure from this encounter is estimated at 80 million. Four additional encounters between jet aircraft and Redoubt ash clouds occurred in the Anchorage area on December 15 and 16, 1989 and February 21, 1990; none resulted in engine failure. Two additional encounters took place on December 17, 1989 when jet airliners encountered the Redoubt cloud over west Texas. At the time of these encounters, the cloud was up to 55 hours old and had traveled in excess of 2,900 nautical miles (5,300 km). Following the December 15 encounters, Anchorage International Airport remained open, however, most airline companies canceled operations for up to several days. As communications between Federal agencies and airlines improved, and as a better understanding of the nature and behavior of ash-rich eruption clouds was achieved, most airlines resumed normal service by early January 1990. The resulting loss of revenue at Anchorage International Airport during several months following the eruption is estimated to total 2.6 million. The impact on general aviation and military operations consisted mostly of cancellation and rerouting of flights.

  13. Emplacement of the final lava dome of the 2009 eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Bull, Katharine F.; Anderson, Steven W.; Diefenbach, Angela K.; Wessels, Rick L.; Henton, Sarah M.

    2013-06-01

    After more than 8 months of precursory activity and over 20 explosions in 12 days, Redoubt Volcano, Alaska began to extrude the fourth and final lava dome of the 2009 eruption on April 4. By July 1 the dome had filled the pre-2009 summit crater and ceased to grow. By means of analysis and annotations of time-lapse webcam imagery, oblique-image photogrammetry techniques and capture and analysis of forward-looking infrared (FLIR) images, we tracked the volume, textural, effusive-style and temperature changes in near-real time over the entire growth period of the dome. The first month of growth (April 4-May 4) produced blocky intermediate- to high-silica andesite lava (59-62.3 wt.% SiO2) that initially formed a round dome, expanding by endogenous growth, breaking the surface crust in radial fractures and annealing them with warmer, fresh lava. On or around May 1, more finely fragmented and scoriaceous andesite lava (59.8-62.2 wt.% SiO2) began to appear at the top of the dome coincident with increased seismicity and gas emissions. The more scoriaceous lava spread radially over the dome surface, while the dome continued to expand from endogenous growth and blocky lava was exposed on the margins and south side of the dome. By mid-June the upper scoriaceous lava had covered 36% of the dome surface area. Vesicularity of the upper scoriaceous lava range from 55 to 66%, some of the highest vesicularity measurements recorded from a lava dome. We suggest that the stability of the final lava dome primarily resulted from sufficient fracturing and clearing of the conduit by preceding explosions that allowed efficient degassing of the magma during effusion. The dome was thus able to grow until it was large enough to exceed the magmastatic pressure in the chamber, effectively shutting off the eruption.

  14. Doppler weather radar observations of the 2009 eruption of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Schneider, David J.; Hoblitt, Richard P.

    2013-01-01

    The U.S. Geological Survey (USGS) deployed a transportable Doppler C-band radar during the precursory stage of the 2009 eruption of Redoubt Volcano, Alaska that provided valuable information during subsequent explosive events. We describe the capabilities of this new monitoring tool and present data captured during the Redoubt eruption. The MiniMax 250-C (MM-250C) radar detected seventeen of the nineteen largest explosive events between March 23 and April 4, 2009. Sixteen of these events reached the stratosphere (above 10 km) within 2–5 min of explosion onset. High column and proximal cloud reflectivity values (50 to 60 dBZ) were observed from many of these events, and were likely due to the formation of mm-sized accretionary tephra-ice pellets. Reflectivity data suggest that these pellets formed within the first few minutes of explosion onset. Rapid sedimentation of the mm-sized pellets was observed as a decrease in maximum detection cloud height. The volcanic cloud from the April 4 explosive event showed lower reflectivity values, due to finer particle sizes (related to dome collapse and related pyroclastic flows) and lack of significant pellet formation. Eruption durations determined by the radar were within a factor of two compared to seismic and pressure-sensor derived estimates, and were not well correlated. Ash dispersion observed by the radar was primarily in the upper troposphere below 10 km, but satellite observations indicate the presence of volcanogenic clouds in the stratosphere. This study suggests that radar is a valuable complement to traditional seismic and satellite monitoring of explosive eruptions.

  15. Water under-saturated phase equilibria of basaltic andesites from Westdahl volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Rader, E. L.; Larsen, J.

    2008-12-01

    The two most abundant gases released from magmatic systems are typically H2O and CO2, however, most phase equilibria studies examining crystallization applied to natural magmatic systems over the past 200 years have relied on H2O-saturated conditions. We will present the results of new phase equilibria experiments run using natural basaltic andesite starting materials from the 1991-1992 eruption of Westdahl volcano, Alaska, examining both H2O-saturated and undersaturated conditions, using a fixed ratio of XH2O ~0.7 and XCO2 ~0.3 in the total volatile budget. The experiments were conducted at total pressures (PTotal) of 0-200 MPa and 900-1050 °C, and fO2 set to the Ni-NiO buffer. Experiments were loaded into gold and Au75Pd25 capsules, and run in a TZM alloy pressure vessel for 48 hours before rapid quenching while still at pressure. After quenching, samples were polished and examined by microprobe and reflective microscopy. Identified mineral phases include plagioclase, clinopyroxene, Fe-Ti oxides, and minor orthopyroxene in both water-saturated and under- saturated experiments. A ~25 to 50 °C shift in temperature, at similar pressures is observed in the plagioclase and pyroxene stability curves when CO2 is added. Solubility models predict relatively low amounts of CO2 dissolved in the melt at similar conditions. Thus, our experiments indicate a significant effect of CO2 on the crystallization of mafic magmas at crustal pressures in volcanic arcs.

  16. The 1989-1990 eruption of Redoubt Volcano, Alaska: impacts on aircraft operations

    USGS Publications Warehouse

    Casadevall, T.J.

    1994-01-01

    The December 1989-June 1990 eruption of Redoubt Volcano affected commercial and military air operations in the vicinity of Anchorage, Alaska. These effects were due to the direct impact of volcanic ash on jet aircraft, as well as to the rerouting and cancellations of flight operations owing to eruptive activity. Between December and February, five commercial jetliners were damaged from ash encounters. The most serious incident took place on December 15, 1989 when a Boeing 747-400 aircraft temporarily lost power of all four engines after encountering an ash cloud as the airplane descended for a landing in Anchorage. While there were no injuries to passengers, the damage to engines, avionics, and aircraft structure from this encounter is estimated at $80 million. Four additional encounters between jet aircraft and Redoubt ash clouds occurred in the Anchorage area on December 15 and 16, 1989 and February 21, 1990; none resulted in engine failure. Two additional encounters took place on December 17, 1989 when jet airliners encountered the Redoubt cloud over west Texas. At the time of these encounters, the cloud was up to 55 hours old and had traveled in excess of 2,900 nautical miles (5,300 km). Following the December 15 encounters, Anchorage International Airport remained open, however, most airline companies canceled operations for up to several days. As communications between Federal agencies and airlines improved, and as a better understanding of the nature and behavior of ash-rich eruption clouds was achieved, most airlines resumed normal service by early January 1990. The resulting loss of revenue at Anchorage International Airport during several months following the eruption is estimated to total $2.6 million. The impact on general aviation and military operations consisted mostly of cancellation and rerouting of flights. ?? 1994.

  17. Anisotropy, repeating earthquakes, and seismicity associated with the 2008 eruption of Okmok Volcano, Alaska

    USGS Publications Warehouse

    Johnson, Jessica H.; Prejean, Stephanie; Savage, Martha K.; Townend, John

    2010-01-01

    We use shear wave splitting (SWS) analysis and double-difference relocation to examine temporal variations in seismic properties prior to and accompanying magmatic activity associated with the 2008 eruption of Okmok volcano, Alaska. Using bispectrum cross-correlation, a multiplet of 25 earthquakes is identified spanning five years leading up to the eruption, each event having first motions compatible with a normal fault striking NE–SW. Cross-correlation differential times are used to relocate earthquakes occurring between January 2003 and February 2009. The bulk of the seismicity prior to the onset of the eruption on 12 July 2008 occurred southwest of the caldera beneath a geothermal field. Earthquakes associated with the onset of the eruption occurred beneath the northern portion of the caldera and started as deep as 13 km. Subsequent earthquakes occurred predominantly at 3 km depth, coinciding with the depth at which the magma body has been modeled using geodetic data. Automated SWS analysis of the Okmok catalog reveals radial polarization outside the caldera and a northwest-southeast polarization within. We interpret these polarizations in terms of a magma reservoir near the center of the caldera, which we model with a Mogi point source. SWS analysis using the same input processing parameters for each event in the multiplet reveals no temporal changes in anisotropy over the duration of the multiplet, suggesting either a short-term or small increase in stress just before the eruption that was not detected by GPS, or eruption triggering by a mechanism other than a change of stress in the system.

  18. Ten Years of Monitoring the Eruption of Shrub Mud Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    McGimsey, R. G.; Evans, W. C.; Bergfeld, D.; McCarthy, S. H.; Hagstrum, J. T.

    2007-12-01

    Shrub mud volcano, one of three in the Klawasi group on the eastern flank of Mount Drum volcano in the Wrangell volcanic field of eastern Alaska, has been erupting warm, saline mud and CO2-rich gas continuously since at least the summer of 1997, following 40 years of repose. The initial eruption in early summer of 1997, documented by Richter and others (1998), involved violent fountaining of mud, up to 6-8 m high, from nearly a dozen vents located near the summit, and quiet effusion from vents located about mid-way down the north flank of the 100-m-high cone. Guided by topography, early emissions of copious amounts of CO2 gas flowed in narrow streams through brushy foliage leaving behind stripes of brown, dead vegetation along the flow paths. The hazard posed by the CO2 emissions was evident from dead birds and mammals found near the vents. Initial surveys of the activity in 1997 recorded water temperatures up to 46°C. A survey in 1999 by Sorey and others (2000) found numerous active vents-many in different locations than those two years earlier-a maximum water temperature of 54°C, and an estimated total discharge of warm water of 50 l/s. Measured CO2 emissions were extrapolated to a discharge rate of 6-12 tonnes/day. The highest water temperature recorded was 57.3°C in 2000, with temperatures gradually declining since. From year to year, we found that eruptive activity migrated amongst clusters of vents, some new and some continuing from 1997. Between the summer of 2003 and the spring of 2004, the system changed dramatically when a large collapse pit formed a few tens of meters from the main summit vents and all previously active vents became inactive. This water-filled circular pit measured 28 m in diameter, up to 9 m deep, and encompassed an area that had previously been unaffected by the eruptive activity. In July 2004, water temperature and discharge at the outlet channel was 37.2°C and 9.4 l/s, respectively. The total CO2 discharge from the roiling pool was 140 l/s (about 20 tonnes/day), and the diffuse efflux (0.13 tonnes/day) was comparable to the 0.23 tonnes/day measured in 1999. Based on discharge and δ13C values of the gas and water phases (-4.6‰ and +1.35‰, respectively) carbon in the reservoir was calculated to be -3.1‰, supporting a mixed magmatic and limestone source for the CO2. Deep pits exposed during the current eruption have provided clues to the possible origin of Shrub, the largest, and highest mud volcano of the Klawasi group. Shrub stands about 100 m high and is an oblong cone in shape. Cross-sections of the material composing the cone reveal a chaotic pile of debris ranging from clay to boulders (angular to subrounded, up to 1.5 m across), the latter too large to have been rafted up by mud and gas venting. Pleistocene glaciers extending into the Copper River Valley from Mount Drum covered the area currently occupied by Shrub. We hypothesize that as the glaciers stagnated and began to retreat, subglacial melting caused by the rising warm mud formed an anomalous moulin that became the receptacle for rock and sediment debris washed in from supraglacier runoff. Thus the constructional form of Shrub is likely a moulin kame.

  19. Formation and Significance of Magmatic Enclaves in From the 2006 Eruption of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Browne, B. L.; Vitale, M. L.

    2011-12-01

    Deposits from the 2006 eruption of Augustine Volcano, Alaska, record a complicated history of open system magmatic processes that produced a suite of intermediate (56.5 to 63.3% SiO2) lithologies containing rare and variably quenched basaltic to basaltic-andesite enclaves (49.5-57.3% SiO2). The eruption transitioned from an explosive phase (Jan 11-28) to a continuous phase (Jan 28-Feb 10) before ending following a month-long effusive phase in March. Whereas the explosive phase is dominated by a low-silica andesite (LSAS, 56.5-58.7% SiO2) lithology, high-silica andesite (HSA, 62.2-63.3% SiO2) is more common during the continuous phase and dense low-silica andesite (DLSA, 56.4-59.3% SiO2) occurs mostly during the effusive phase. Enclaves occur in all lithologies, although most commonly in DLSA and LSAS. Point-counting of enclaves in outcrop reveals an average abundance of <1 volume percent, however, some DLSA blocks contained in a unusually large pyroclastic flow deposit emplaced at the end of the explosive phase near Rocky Point contain up to 3 volume percent enclaves. Transitional-type enclaves exist, but the two main end-member types of magmatic enclaves are P-type ('primitive') and H-type ('hybrid'). P-type enclaves range from 2-5 cm in diameter and are black with highly vesicular, acicular, and glassy interiors surrounded by quenched and cuspate margins, range in composition from 49.5-52% SiO2, and contain abundant olivine and sparse plagioclase antecrysts. H-type enclaves range in diameter from 1 to 10 cm and are variably gray with poorly vesicular interiors and underdeveloped cuspate margins, range from 52-57.3% SiO2, and contain equant crystals in a glass-poor groundmass with abundant plagioclase antecrysts and rare olivine. Many H-type enclaves, which are the only enclave type observed in the HSA lithology, are indistinguishable from LSAS and DLSA samples in terms of whole-rock composition, mineral compositions, and texture. All enclaves plot linearly in major and minor element graphical space in terms of whole-rock composition, and glass compositions from P-type enclaves also plot linearly with the rest of the 2006 sample suite. Magnetite-ilmenite pairs in P-type enclaves record core temperatures ranging from 975-1120°C compared to 840-940°C for H-type enclaves (fO2 increases with decreasing temperature from NNO+0.5 to +2.0) and core to rim diffusion profiles in magnetite grains from P-type enclaves from explosive and effusive phases indicate an average timescale of 1-month between heating of crystals via basalt replenishment and eruption. A key finding from this study is that magmatic enclaves produced during the 2006 eruption of Augustine Volcano record a complex and multi-step mixing and mingling scenario between intruding basalt and resident silicic mush, and possibly gabbroic cumulates/wall rock, that is inconsistent with any single currently employed mingling model (e.g., buoyant lift-off of vesiculated and undercooled basalt, prolonged undercooling of intruded basalt punctuated by subsequent intrusions, enclave dissagregation and ripening, or violent intrusion of bubbly basaltic plumes) that has been used to explain magmatic enclave formation at other arc systems characterized by lower magma temperature, higher crystallinity, and larger eruptive volumes (e.g., Unzen Volcano, Mt. Lassen, Soufriere Hills).

  20. Lahar Inundation of the Drift River Valley During the 2009 Eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Scott, W. E.; Pierson, T. C.; Major, J. J.

    2009-12-01

    Redoubt Volcano in south-central Alaska began its most recent eruption on March 15 and erupted explosively at least 20 times between then and April 4, 2009. The 3110 m high, snow-and-ice-clad stratovolcano includes a circular, ice-filled summit crater that is breached to the north. The volcano supports about 4 km3 of ice and snow and about 1 km3 of this makes up Drift glacier on the north side of the volcano. Explosive eruptions between March 22 and April 4, which included the destruction of at least two lava domes, triggered two large lahars in the Drift River valley on March 23 and April 4, and several smaller lahars between March 24 and March 31. The heights of mud lines, character of deposits examined in the field, areas of deposition, and estimates of flow width, depth, and velocity revealed that the lahars on March 23 and April 4 were the largest mass flows of the eruption. In the ~1.5-km-wide upper Drift River valley, flow depths averaged about 10 m, flow velocities, although not measured directly, were at least 10-14 m/s, and peak discharges were on the order of 105 m3/s. Depositional areas (about 12.5 km2) and volumes (0.063-0.088 km3) were similar. Despite these similarities, the two lahars had very different compositions and origins. The March 23 lahar was a flowing slurry of snow and ice that entrained tablular blocks of river ice, seasonal snow in the valley, and glacier ice eroded from Drift glacier. Its deposit was up to 5 m thick, and contained roughly 30% sediment, rock debris and water, and 70% or more river and glacier ice. It was frozen soon after it was emplaced and later buried by the April 4 lahar. Juvenile material has not yet been found in the deposit. The lahar of April 4, in contrast, was a hyperconcentrated flow, as interpreted from massive to faintly and horizontally stratified sand to fine gravel deposits up to 4 m thick. Gravel clasts were predominantly juvenile andesite. We infer the March 23 lahar to have been initiated by a rapid series of vent-clearing explosions that blasted up through at least 50 m of crater-filling glacier ice and snow, producing a voluminous release of meltwater from the crater. The resulting flood eroded and entrained snow, fragments of glacier and river ice, and liquid water along its flow path. Small-volume pyroclastic flows, possibly associated with minor eruption-column collapses, may have contributed additional meltwater to the lahar. Meltwater generated by subglacial hydrothermal activity and stored beneath Drift glacier may have been ejected or released rapidly as well. Juvenile clasts in the April 4 deposit indicate that this lahar was initiated when hot dome-collapse pyroclastic flows scoured snow, ice, and rock debris from the upper Drift glacier and produced a meltwater flood that further entrained sediment. The two lahars, comparable in volume to the largest lahars of the 1989-90 Redoubt eruption, produced about 5-7 m of channel aggradation in the lower Drift River valley and inundated an oil storage and transfer facility located there.

  1. Tsunami generation by pyroclastic flow during the 3500-year B.P. caldera-forming eruption of Aniakchak Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Neal, C. A.

    A discontinuous pumiceous sand, a few centimeters to tens of centimeters thick, is located up to 15m above mean high tide within Holocene peat along the northern Bristol Bay coastline of Alaska. The bed consists of fine-to-coarse, poorly to moderately well-sorted, pumice-bearing sand near the top of a 2-m-thick peat sequence. The sand bed contains rip-up clasts of peat and tephra and is unique in the peat sequence. Major element compositions of juvenile glass from the deposit and radiocarbon dating of enclosing peat support correlation of the pumiceous sand with the caldera-forming eruption of Aniakchak Volcano. The distribution of the sand and its sedimentary characteristics are consistent with emplacement by tsunami. The pumiceous sand most likely represents redeposition by tsunami of climactic fallout tephra and beach sand during the approximately 3.5ka Aniakchak caldera-forming eruption on the Alaska Peninsula. We propose that a tsunami was generated by the sudden entrance of a rapidly moving, voluminous pyroclastic flow from Aniakchak into Bristol Bay. A seismic trigger for the tsunami is unlikely, because tectonic structures suitable for tsunami generation are present only south of the Alaska Peninsula. The pumiceous sand in coastal peat of northern Bristol Bay is the first documented geologic evidence of a tsunami initiated by a volcanic eruption in Alaska.

  2. Interferometric synthetic aperture radar study of Okmok volcano, Alaska, 1992-2003: Magma supply dynamics and postemplacement lava flow deformation

    USGS Publications Warehouse

    Lu, Zhiming; Masterlark, Timothy; Dzurisin, D.

    2005-01-01

    Okmok volcano, located in the central Aleutian arc, Alaska, is a dominantly basaltic complex topped with a 10-km-wide caldera that formed circa 2.05 ka. Okmok erupted several times during the 20th century, most recently in 1997; eruptions in 1945, 1958, and 1997 produced lava flows within the caldera. We used 80 interferometric synthetic aperture radar (InSAR) images (interferograms) to study transient deformation of the volcano before, during, and after the 1997 eruption. Point source models suggest that a magma reservoir at a depth of 3.2 km below sea level, located beneath the center of the caldera and about 5 km northeast of the 1997 vent, is responsible for observed volcano-wide deformation. The preeruption uplift rate decreased from about 10 cm yr-1 during 1992-1993 to 2 ??? 3 cm yr-1 during 1993-1995 and then to about -1 ??? -2 cm yr-1 during 1995-1996. The posteruption inflation rate generally decreased with time during 1997-2001, but increased significantly during 2001-2003. By the summer of 2003, 30 ??? 60% of the magma volume lost from the reservoir in the 1997 eruption had been replenished. Interferograms for periods before the 1997 eruption indicate consistent subsidence of the surface of the 1958 lava flows, most likely due to thermal contraction. Interferograms for periods after the eruption suggest at least four distinct deformation processes: (1) volcano-wide inflation due to replenishment of the shallow magma reservoir, (2) subsidence of the 1997 lava flows, most likely due to thermal contraction, (3) deformation of the 1958 lava flows due to loading by the 1997 flows, and (4) continuing subsidence of 1958 lava flows buried beneath 1997 flows. Our results provide insights into the postemplacement behavior of lava flows and have cautionary implications for the interpretation of inflation patterns at active volcanoes.

  3. Nonlinear estimation of geometric parameters in finite element models of volcano deformation: Application to the 1997 eruption of Okmok volcano, Alaska.

    NASA Astrophysics Data System (ADS)

    Masterlark, T.; Feigl, K.; Haney, M. M.; Stone, J.; Thurber, C. H.; Ronchin, E.

    2011-12-01

    The internal structure, loading processes, and effective boundary conditions of a volcano control the deformation observed at the Earth's surface. Using finite element models, we simulate the response due to a pressurized magma chamber embedded in a domain having an arbitrary geometry and distribution of elastic material properties. The ability to impose perturbations of the source position and automatically generate an acceptable mesh has been an obstacle to implementing nonlinear inverse analyses of geodetic data to estimate the position of a magma chamber within the mesh of a finite element model. We use the Pinned Mesh Perturbation method (PMP) to automatically generate the mesh following perturbations to geometric parameters such as the depth of the source. For example, we analyze the 1997 eruption of Okmok volcano, Alaska. To describe the co-eruptive deformation field observed by synthetic aperture radar interferometry (InSAR), we solve a nonlinear inverse problem by combining PMP with nested Monte Carlo methods. The solution yields estimates and uncertainties for parameters that characterize the depressurization and location of the magma chamber beneath Okmok's caldera. The three-dimensional finite element models used in the PMP method simulate the heterogeneous distribution of material properties derived from seismic tomography and account for the irregular geometry of the topography and bathymetry. The fit of this heterogeneous configuration to the InSAR data is a significant improvement, at the 95% confidence level, compared to the fit of a corresponding finite element model having homogeneous material properties. The estimated depth of an assumed spherical magma chamber, embedded in a domain having a heterogeneous distribution of material properties, is 3530 +/- 30 m with respect to mean sea level. This estimated depth is consistent with constraints from rock mechanics and very-long-period tremor. The methods presented here allow us to construct deformation models that unite seismic and geodetic observations in an effort to achieve a deeper understanding of active volcanoes.

  4. Comparison of magmatic structures beneath Redoubt (Alaska) and Toba (Northern Sumatra) volcanoes derived from local earthquake tomography studies

    NASA Astrophysics Data System (ADS)

    Kasatkina, Ekaterina; Koulakov, Ivan; West, Michael

    2014-05-01

    We present the results of seismic tomography studies of two different volcanoes - Mt. Redoubt and Toba caldera. These two subduction related volcanoes have different ages and scales of eruption activity. Velocity model beneath the Redoubt volcano is based on tomographic inversion of P- and S- arrival time data from over 4000 local earthquakes recorded by 19 stations since 1989 to 2012 provided by the Alaskan Volcano Observatory (University of Fairbanks). Just below the volcano edifice we observe an anomaly of high Vp/Vs ratio reaching 2.2 which is seen down to 2- 3 km depth. This indicates a presence of partially molten substance or fluid filled rocks. We can suggest that anomaly area matches with volcano magma chamber. One of the previous velocity models of Toba caldera was obtained by Koulakov et al. (2009) and was based on data recorded by temporary network from January to May 1995. In this study this "old" dataset was supplemented with "new" data recorded by a temporary network deployed in approximately same area by GFZ-Potsdam from May to November 2008. We have manually picked the arrival times from the local events recorded by the later experiment and then performed the tomography inversion for the combined dataset using the LOTOS code (Koulakov, 2009). In the uppermost layers we observe strong low-velocity P- and S- anomalies within the Caldera which can be interpreted by the presence of think sediments filling the caldera. In the lower crust and uppermost mantle we observe a vertical anomaly of low P- and S-velocities which probably represent the path of conduits which link the caldera area with the slab. Similar to Redoubt volcano, resulting velocity model of Toba has an increased value of Vp/Vs ratio that indicates a presence of magma reservoir. Comparison of the tomographic results obtained for the completely different volcanic systems helps in understanding some basic principles of feeding the volcanoes. This study was partly supported by the Project #7.3 of BES RAS. 1. Koulakov I., T. Yudistira, B.-G. Luehr, and Wandono, 2009, P, S velocity and VP/VS ratio beneath the Toba caldera complex (Northern Sumatra) from local earthquake tomography, Geophys. J. Int., 177, p. 1121-1139. 2. Koulakov I., 2009, LOTOS code for local earthquake tomographic inversion. Benchmarks for testing tomographic algorithms, Bulletin of the Seismological Society of America, Vol. 99, No. 1, pp. 194-214.

  5. Acoustic measurements of the 1999 basaltic eruption of Shishaldin volcano, Alaska 1. Origin of Strombolian activity

    USGS Publications Warehouse

    Vergniolle, S.; Boichu, M.; Caplan-Auerbach, J.

    2004-01-01

    The 1999 basaltic eruption of Shishaldin volcano (Alaska, USA) displayed both classical Strombolian activity and an explosive Subplinian plume. Strombolian activity at Shishaldin occurred in two major phases following the Subplinian activity. In this paper, we use acoustic measurements to interpret the Strombolian activity. Acoustic measurements of the two Strombolian phases show a series of explosions that are modeled by the vibration of a large overpressurised cylindrical bubble at the top of the magma column. Results show that the bubble does not burst at its maximum radius, as expected if the liquid film is stretched beyond its elasticity. But bursting occurs after one cycle of vibration, as a consequence of an instability of the air-magma interface close to the bubble minimum radius. During each Strombolian period, estimates of bubble length and overpressure are calculated. Using an alternate method based on acoustic power, we estimate gas velocity to be 30-60 m/s, in very good agreement with synthetic waveforms. Although there is some variation within these parameters, bubble length and overpressure for the first Strombolian phase are found to be ??? 82 ?? 11 m and 0.083 MPa. For the second Strombolian phase, bubble length and overpressure are estimated at 24 ?? 12 m and 0.15 MPa for the first 17 h after which bubble overpressure shows a constant increase, reaching a peak of 1.4 MPa, just prior to the end of the second Strombolian phase. This peak suggests that, at the time, the magma in the conduit may contain a relatively large concentration of small bubbles. Maximum total gas volume and gas fluxes at the surface are estimated to be 3.3 ?? 107 and 2.9 ?? 103 m3/s for the first phase and 1.0 ?? 108 and 2.2 ?? 103 m3/s for the second phase. This gives a mass flux of 1.2 ?? 103 and 8.7 ?? 102 kg/s, respectively, for the first and the second Strombolian phases. ?? 2004 Elsevier B.V. All rights reserved.

  6. RESEARCH: Effects of Recent Volcanic Eruptions on Aquatic Habitat in the Drift River, Alaska, USA: Implications at Other Cook Inlet Region Volcanoes.

    PubMed

    DORAVA; MILNER

    1999-02-01

    / Numerous drainages supporting productive salmon habitat are surrounded by active volcanoes on the west side of Cook Inlet in south-central Alaska. Eruptions have caused massive quantities of flowing water and sediment to enter the river channels emanating from glaciers and snowfields on these volcanoes. Extensive damage to riparian and aquatic habitat has commonly resulted, and benthic macroinvertebrate and salmonid communities can be affected. Because of the economic importance of Alaska's fisheries, detrimental effects on salmonid habitat can have significant economic implications. The Drift River drains glaciers on the northern and eastern flanks of Redoubt Volcano. During and following eruptions in 1989-1990, severe physical disturbances to the habitat features of the river adversely affected the fishery. Frequent eruptions at other Cook Inlet region volcanoes exemplify the potential effects of volcanic activity on Alaska's important commercial, sport, and subsistence fisheries. Few studies have documented the recovery of aquatic habitat following volcanic eruptions. The eruptions of Redoubt Volcano in 1989-1990 offered an opportunity to examine the recovery of the macroinvertebrate community. Macroinvertebrate community composition and structure in the Drift River were similar in both undisturbed and recently disturbed sites. Additionally, macroinvertebrate samples from sites in nearby undisturbed streams were highly similar to those from some Drift River sites. This similarity and the agreement between the Drift River macroinvertebrate community composition and that predicted by a qualitative model of typical macroinvertebrate communities in glacier-fed rivers indicate that the Drift River macroinvertebrate community is recovering five years after the disturbances associated with the most recent eruptions of Redoubt Volcano. KEY WORDS: Aquatic habitat; Volcanoes; Lahars; Lahar-runout flows; Macroinvertebrates; Community structure; Community composition; Taxonomic similarity PMID:9852188

  7. Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska

    USGS Publications Warehouse

    Calvert, Andrew T.; Moore, Richard B.; McGimsey, Robert G.

    2005-01-01

    High-precision 40Ar/39Ar geochronology of selected lavas from Westdahl Volcano places time constraints on several key prehistoric eruptive phases of this large active volcano. A dike cutting old pyroclastic-flow and associated lahar deposits from a precursor volcano yields an age of 1,654+/-11 k.y., dating this precursor volcano as older than early Pleistocene. A total of 11 geographically distributed lavas with ages ranging from 47+/-14 to 127+/-2 k.y. date construction of the Westdahl volcanic center. Lava flows cut by an apparent caldera-rim structure yielded ages of 81+/-5 and 121+/-8 k.y., placing a maximum date of 81 ka on caldera formation. Late Pleistocene and Holocene lavas fill the caldera, but most of them are obscured by the large summit icecap.

  8. Numerical simulation of tsunami generation by cold volcanic mass flows at Augustine Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, C.F.; Watts, P.; Walder, J.S.

    2006-01-01

    Many of the world's active volcanoes are situated on or near coastlines. During eruptions, diverse geophysical mass flows, including pyroclastic flows, debris avalanches, and lahars, can deliver large volumes of unconsolidated debris to the ocean in a short period of time and thereby generate tsunamis. Deposits of both hot and cold volcanic mass flows produced by eruptions of Aleutian arc volcanoes are exposed at many locations along the coastlines of the Bering Sea, North Pacific Ocean, and Cook Inlet, indicating that the flows entered the sea and in some cases may have initiated tsunamis. We evaluate the process of tsunami generation by cold granular subaerial volcanic mass flows using examples from Augustine Volcano in southern Cook Inlet. Augustine Volcano is the most historically active volcano in the Cook Inlet region, and future eruptions, should they lead to debris-avalanche formation and tsunami generation, could be hazardous to some coastal areas. Geological investigations at Augustine Volcano suggest that as many as 12-14 debris avalanches have reached the sea in the last 2000 years, and a debris avalanche emplaced during an A.D. 1883 eruption may have initiated a tsunami that was observed about 80 km east of the volcano at the village of English Bay (Nanwalek) on the coast of the southern Kenai Peninsula. Numerical simulation of mass-flow motion, tsunami generation, propagation, and inundation for Augustine Volcano indicate only modest wave generation by volcanic mass flows and localized wave effects. However, for east-directed mass flows entering Cook Inlet, tsunamis are capable of reaching the more populated coastlines of the southwestern Kenai Peninsula, where maximum water amplitudes of several meters are possible.

  9. Vapor saturation and accumulation in magmas of the 1989 1990 eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Gerlach, Terrence M.; Westrich, Henry R.; Casadevall, Thomas J.; Finnegan, David L.

    1994-08-01

    The 1989-1990 eruption of Redoubt Volcano, Alaska, provided an opportunity to compare petrologic estimates of SO 2 and Cl emissions with estimates of SO 2 emissions based on remote sensing data and estimates of Cl emissions based on plume sampling. In this study, we measure the sulfur and chlorine contents of melt inclusions and matrix glasses in the eruption products to determine petrologic estimates of SO 2 and Cl emissions. We compare the results with emission estimates based on COSPEC and TOMS data for SO 2 and data for Cl/SO 2 in plume samples. For the explosive vent clearing period (December 14-22, 1989), the petrologic estimate for SO 2 emission is 21,000 tons, or ~12% of a TOMS estimate of 175,000 tons. For the dome growth period (December 22, 1989 to mid-June 1990), the petrologic estimate for SO 2 emission is 18,000 tons, or ~3% of COSPEC-based estimates of 572,000-680,000 tons. The petrologic estimates give a total SO 2 emission of only 39,000 tons compared to an integrated TOMS/COSPEC emission estimate of ~1,000,000 tons for the whole eruption, including quiescent degassing after mid-June 1990. Petrologic estimates also appear to underestimate Cl emissions, but apparent HCl scavenging in the plume complicates Cl emission comparisons. Several potential sources of 'excess sulfur' often invoked to explain petrologic SO 2 deficits are concluded to be unlikely for the 1989-1990 Redoubt eruption — e.g., breakdown of sulfides, breakdown of anhydrite, release of SO 2 from a hydrothermal system, degassing of commingled infusions of basalt in the magma chamber, and syn-eruptive degassing of sulfur from melt present in non-erupted magma. Leakage and/or diffusion of sulfur from melt inclusions do not provide convincing explanations for the petrologic SO 2 deficits either. The main cause of low petrologic estimates for SO 2 is that melt inclusions do not represent the total sulfur content of the Redoubt magmas, which were vapor-saturated magmas carrying most of their sulfur in an accumulated vapor phase. Almost all the sulfur of the SO 2 emissions was present prior to emission as accumulated magmatic vapor at 6-10 km depth in the magma that supplied the eruption; whole-rock normalized concentrations of gaseous excess S in these magmas remained at ~0.2 wt.% throughout the eruption, equivalent to ~0.7 vol.% at depth. Data for CO 2 emissions during the eruption indicate that CO 2 at whole-rock concentrations of ~0.6 wt.% in the erupted magma was a key factor in creating the vapor saturation and accumulation condition making a vapor phase source of excess sulfur possible at depth. When explosive volcanism involves magma with accumulated vapor, melt inclusions do not provide a sufficient basis for predicting SO 2 emissions. Thus, petrologic estimates made for SO 2 emissions during explosive eruptions of the past may be too low and may significantly underestimate impacts on climate and the chemistry of the atmosphere.

  10. Vapor saturation and accumulation in magmas of the 1989-1990 eruption of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Gerlach, T.M.; Westrich, H.R.; Casadevall, T.J.; Finnegan, David L.

    1994-01-01

    The 1989-1990 eruption of Redoubt Volcano, Alaska, provided an opportunity to compare petrologic estimates of SO2 and Cl emissions with estimates of SO2 emissions based on remote sensing data and estimates of Cl emissions based on plume sampling. In this study, we measure the sulfur and chlorine contents of melt inclusions and matrix glasses in the eruption products to determine petrologic estimates of SO2 and Cl emissions. We compare the results with emission estimates based on COSPEC and TOMS data for SO2 and data for Cl/SO2 in plume samples. For the explosive vent clearing period (December 14-22, 1989), the petrologic estimate for SO2 emission is 21,000 tons, or ~12% of a TOMS estimate of 175,000 tons. For the dome growth period (December 22, 1989 to mid-June 1990), the petrologic estimate for SO2 emission is 18,000 tons, or ~3% of COSPEC-based estimates of 572,000-680,000 tons. The petrologic estimates give a total SO2 emission of only 39,000 tons compared to an integrated TOMS/COSPEC emission estimate of ~1,000,000 tons for the whole eruption, including quiescent degassing after mid-June 1990. Petrologic estimates also appear to underestimate Cl emissions, but apparent HCl scavenging in the plume complicates Cl emission comparisons. Several potential sources of 'excess sulfur' often invoked to explain petrologic SO2 deficits are concluded to be unlikely for the 1989-1990 Redoubt eruption - e.g., breakdown of sulfides, breakdown of anhydrite, release of SO2 from a hydrothermal system, degassing of commingled infusions of basalt in the magma chamber, and syn-eruptive degassing of sulfur from melt present in non-erupted magma. Leakage and/or diffusion of sulfur from melt inclusions do not provide convincing explanations for the petrologic SO2 deficits either. The main cause of low petrologic estimates for SO2 is that melt inclusions do not represent the total sulfur content of the Redoubt magmas, which were vapor-saturated magmas carrying most of their sulfur in an accumulated vapor phase. Almost all the sulfur of the SO2 emissions was present prior to emission as accumulated magmatic vapor at 6-10 km depth in the magma that supplied the eruption; whole-rock normalized concentrations of gaseous excess S in these magmas remained at ~0.2 wt.% throughout the eruption, equivalent to ~0.7 vol.% at depth. Data for CO2 emissions during the eruption indicate that CO2 at whole-rock concentrations of ~0.6 wt.% in the erupted magma was a key factor in creating the vapor saturation and accumulation condition making a vapor phase source of excess sulfur possible at depth. When explosive volcanism involves magma with accumulated vapor, melt inclusions do not provide a sufficient basis for predicting SO2 emissions. Thus, petrologic estimates made for SO2 emissions during explosive eruptions of the past may be too low and may significantly underestimate impacts on climate and the chemistry of the atmosphere. ?? 1994.

  11. Volcanic Ash From 1989 Mt. Redoubt Eruption, Alaska

    The Alaska Volcano Observatory has recently installed a state of the art scanning electronic microscope (SEM) at its facility in Anchorage using ARRA funding.  The SEM will be used to analyze volcanic deposits for their composition, texture, and other valuable information that will enable us to...

  12. Perennial snow and ice volumes on Iliamna Volcano, Alaska, estimated with ice radar and volume modeling

    USGS Publications Warehouse

    Trabant, Dennis C.

    1999-01-01

    The volume of four of the largest glaciers on Iliamna Volcano was estimated using the volume model developed for evaluating glacier volumes on Redoubt Volcano. The volume model is controlled by simulated valley cross sections that are constructed by fitting third-order polynomials to the shape of the valley walls exposed above the glacier surface. Critical cross sections were field checked by sounding with ice-penetrating radar during July 1998. The estimated volumes of perennial snow and glacier ice for Tuxedni, Lateral, Red, and Umbrella Glaciers are 8.6, 0.85, 4.7, and 0.60 cubic kilometers respectively. The estimated volume of snow and ice on the upper 1,000 meters of the volcano is about 1 cubic kilometer. The volume estimates are thought to have errors of no more than ?25 percent. The volumes estimated for the four largest glaciers are more than three times the total volume of snow and ice on Mount Rainier and about 82 times the total volume of snow and ice that was on Mount St. Helens before its May 18, 1980 eruption. Volcanoes mantled by substantial snow and ice covers have produced the largest and most catastrophic lahars and floods. Therefore, it is prudent to expect that, during an eruptive episode, flooding and lahars threaten all of the drainages heading on Iliamna Volcano. On the other hand, debris avalanches can happen any time. Fortunately, their influence is generally limited to the area within a few kilometers of the summit.

  13. Determining the seismic source mechanism and location for an explosive eruption with limited observational data: Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Dawson, Phillip B.; Chouet, Bernard A.; Power, John

    2011-02-01

    Waveform inversions of the very-long-period components of the seismic wavefield produced by an explosive eruption that occurred on 11 January, 2006 at Augustine Volcano, Alaska constrain the seismic source location to near sea level beneath the summit of the volcano. The calculated moment tensors indicate the presence of a volumetric source mechanism. Systematic reconstruction of the source mechanism shows the source consists of a sill intersected by either a sub-vertical east-west trending dike or a sub-vertical pipe and a weak single force. The trend of the dike may be controlled by the east-west trending Augustine-Seldovia arch. The data from the network of broadband sensors is limited to fourteen seismic traces, and synthetic modeling confirms the ability of the network to recover the source mechanism. The synthetic modeling also provides a guide to the expected capability of a broadband network to resolve very-long-period source mechanisms, particularly when confronted with limited observational data.

  14. Determining the seismic source mechanism and location for an explosive eruption with limited observational data: Augustine Volcano, Alaska

    USGS Publications Warehouse

    Dawson, P.B.; Chouet, B.A.; Power, J.

    2011-01-01

    Waveform inversions of the very-long-period components of the seismic wavefield produced by an explosive eruption that occurred on 11 January, 2006 at Augustine Volcano, Alaska constrain the seismic source location to near sea level beneath the summit of the volcano. The calculated moment tensors indicate the presence of a volumetric source mechanism. Systematic reconstruction of the source mechanism shows the source consists of a sill intersected by either a sub-vertical east-west trending dike or a sub-vertical pipe and a weak single force. The trend of the dike may be controlled by the east-west trending Augustine-Seldovia arch. The data from the network of broadband sensors is limited to fourteen seismic traces, and synthetic modeling confirms the ability of the network to recover the source mechanism. The synthetic modeling also provides a guide to the expected capability of a broadband network to resolve very-long-period source mechanisms, particularly when confronted with limited observational data. Copyright 2011 by the American Geophysical Union.

  15. Effects of recent volcanic eruptions on aquatic habitat in the Drift River, Alaska, USA: Implications at other Cook Inlet region volcanoes

    USGS Publications Warehouse

    Dorava, J.M.; Milner, A.M.

    1999-01-01

    Numerous drainages supporting productive salmon habitat are surrounded by active volcanoes on the west side of Cook Inlet in south-central Alaska. Eruptions have caused massive quantities of flowing water and sediment to enter the river channels emanating from glaciers and snowfields on these volcanoes. Extensive damage to riparian and aquatic habitat has commonly resulted, and benthic macroinvertebrate and salmonid communities can be affected. Because of the economic importance of Alaska's fisheries, detrimental effects on salmonid habitat can have significant economic implications. The Drift River drains glaciers on the northern and eastern flanks of Redoubt Volcano: During and following eruptions in 1989-1990, severe physical disturbances to the habitat features of the river adversely affected the fishery. Frequent eruptions at other Cook Inlet region volcanoes exemplify the potential effects of volcanic activity on Alaska's important commercial, sport, and subsistence fisheries. Few studies have documented the recovery of aquatic habitat following volcanic eruptions. The eruptions of Redoubt Volcano in 1989-1990 offered an opportunity to examine the recovery of the macroinvertebrate community. Macroinvertebrate community composition and structure in the Drift River were similar in both undisturbed and recently disturbed sites. Additionally, macroinvertebrate samples from sites in nearby undisturbed streams were highly similar to those from some Drift River sites. This similarity and the agreement between the Drift River macroinvertebrate community composition and that predicted by a qualitative model of typical macroinvertebrate communities in glacier-fed rivers indicate that the Drift River macroinvertebrate community is recovering five years after the disturbances associated with the most recent eruptions of Redoubt Volcano.

  16. The Hawaiian Volcano Observatory's current approach to forecasting lava flow hazards (Invited)

    NASA Astrophysics Data System (ADS)

    Kauahikaua, J. P.

    2013-12-01

    Hawaiian Volcanoes are best known for their frequent basaltic eruptions, which typically start with fast-moving channelized `a`a flows fed by high eruptions rates. If the flows continue, they generally transition into pahoehoe flows, fed by lower eruption rates, after a few days to weeks. Kilauea Volcano's ongoing eruption illustrates this--since 1986, effusion at Kilauea has mostly produced pahoehoe. The current state of lava flow simulation is quite advanced, but the simplicity of the models mean that they are most appropriately used during the first, most vigorous, days to weeks of an eruption - during the effusion of `a`a flows. Colleagues at INGV in Catania have shown decisively that MAGFLOW simulations utilizing satellite-derived eruption rates can be effective at estimating hazards during the initial periods of an eruption crisis. However, the algorithms do not simulate the complexity of pahoehoe flows. Forecasts of lava flow hazards are the most common form of volcanic hazard assessments made in Hawai`i. Communications with emergency managers over the last decade have relied on simple steepest-descent line maps, coupled with empirical lava flow advance rate information, to portray the imminence of lava flow hazard to nearby communities. Lavasheds, calculated as watersheds, are used as a broader context for the future flow paths and to advise on the utility of diversion efforts, should they be contemplated. The key is to communicate the uncertainty of any approach used to formulate a forecast and, if the forecast uses simple tools, these communications can be fairly straightforward. The calculation of steepest-descent paths and lavasheds relies on the accuracy of the digital elevation model (DEM) used, so the choice of DEM is critical. In Hawai`i, the best choice is not the most recent but is a 1980s-vintage 10-m DEM--more recent LIDAR and satellite radar DEM are referenced to the ellipsoid and include vegetation effects. On low-slope terrain, steepest descent lines calculated on a geoid-based DEM may differ significantly from those calculated on an ellipsoid-based DEM. Good estimates of lava flow advance rates can be obtained from empirical compilations of historical advance rates of Hawaiian lava flows. In this way, rates appropriate for observed flow types (`a`a or pahoehoe, channelized or not) can be applied. Eruption rate is arguably the most important factor, while slope is also significant for low eruption rates. Eruption rate, however, remains the most difficult parameter to estimate during an active eruption. The simplicity of the HVO approach is its major benefit. How much better can lava-flow advance be forecast for all types of lava flows? Will the improvements outweigh the increased uncertainty propagated through the simulation calculations? HVO continues to improve and evaluate its lava flow forecasting tools to provide better hazard assessments to emergency personnel.

  17. Catalog of earthquake hypocenters at Alaskan Volcanoes: January 1 through December 31, 2011

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Searcy, Cheryl K.

    2012-01-01

    Between January 1 and December 31, 2011, the Alaska Volcano Observatory (AVO) located 4,364 earthquakes, of which 3,651 occurred within 20 kilometers of the 33 volcanoes with seismograph subnetworks. There was no significant seismic activity above background levels in 2011 at these instrumented volcanic centers. This catalog includes locations, magnitudes, and statistics of the earthquakes located in 2011 with the station parameters, velocity models, and other files used to locate these earthquakes.

  18. A distal earthquake cluster concurrent with the 2006 explosive eruption of Augustine Volcano, Alaska

    USGS Publications Warehouse

    Fisher, M.A.; Ruppert, N.A.; White, R.A.; Wilson, F.H.; Comer, D.; Sliter, R.W.; Wong, F.L.

    2009-01-01

    Clustered earthquakes located 25??km northeast of Augustine Volcano began about 6??months before and ceased soon after the volcano's 2006 explosive eruption. This distal seismicity formed a dense cluster less than 5??km across, in map view, and located in depth between 11??km and 16??km. This seismicity was contemporaneous with sharply increased shallow earthquake activity directly below the volcano's vent. Focal mechanisms for five events within the distal cluster show strike-slip fault movement. Cluster seismicity best defines a plane when it is projected onto a northeast-southwest cross section, suggesting that the seismogenic fault strikes northwest. However, two major structural trends intersect near Augustine Volcano, making it difficult to put the seismogenic fault into a regional-geologic context. Specifically, interpretation of marine multichannel seismic-reflection (MCS) data shows reverse faults, directly above the seismicity cluster, that trend northeast, parallel to the regional geologic strike but perpendicular to the fault suggested by the clustered seismicity. The seismogenic fault could be a reactivated basement structure.

  19. Glacier ice-volume modeling and glacier volumes on Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Trabant, Dennis C.; Hawkins, Daniel B.

    1997-01-01

    Assessment of ice volumes and hydrologic hazards on Redoubt Volcano began four months before the 1989-90 eruptions removed 0.29 cubic kilometer of perennial snow and ice from Drift glacier. A volume model was developed for evaluating glacier volumes on Redoubt Volcano. The volume model is based on third-order polynomial simulations of valley cross sections. The third-order polynomial is an interpolation from the valley walls exposed above glacier surfaces and takes advantage of ice-thickness measurements. The fortuitous 1989-90 eruptions removed the ice from a 4.5-kilometer length of Drift glacier, providing a unique opportunity for verification of the volume model. A 2.5-kilometer length was chosen in the denuded glacier valley and the ice volume was measured by digitally comparing two new maps: one derived from the most recent pre-eruption 1979 aerial photographs and the other from post-eruption 1990 aerial photographs. The measured volume in the reference reach was 99 x 106 cubic meters, about 1 percent less than was estimated by the volume model. The volume estimate produced by this volume model was much closer to the measured volume than was the volume estimated by other techniques. The verified volume model was used to evaluate the total volume of perennial snow and glacier ice on Redoubt Volcano, which was estimated to be 4.1?0.8 cubic kilometers. Substantial snow and ice covers on volcanoes exacerbate the hydrologic hazards associated with eruptions. The volume on Redoubt Volcano is about 23 times the volume that was present on Mount St. Helens before its 1980 eruption, which generated lahars and floods.

  20. Seismic investigations of subsurface volcanic structures and processes at Mount Spurr, Alaska and Soufriere Hills Volcano, Montserrat, West Indies

    NASA Astrophysics Data System (ADS)

    Power, John A.

    Seismological techniques are used to infer the subsurface structures and volcanic processes at two recently active volcanoes: Mount Spurr, Alaska, and Soufriere Hills Volcano, Montserrat, West Indies. The three-dimensional P-wave velocity structure of Mount Spurr is determined to depths of 10 km by tomographic inversion of 3,754 P-wave arrival times from local earthquakes. Results show a prominent low-velocity zone beneath the southeast flank of Crater Peak extending from the surface to 3--4 km below sea level, spatially coincident with an active geothermal system. Beneath Crater Peak an approximately 3-km-wide zone of relatively low velocities correlates with a near vertical band of seismicity, suggestive of a magma conduit. No large low-velocity zone indicative of a magma chamber occurs within the upper 10 km of the crust. In the three years bracketing the 1992 eruptions of Mount Spurr's Crater Peak vent, approximately 2,500 located events were classified as Volcano-Tectonic (VT) earthquakes, Long-Period (LP) events, or Hybrid events. An unusual mix of VT, LP, and hybrid events at 20 to 40 km depth began coincident with the onset of unrest and peaked shortly after eruptive activity ended. The classified seismic events are combined with geophysical and geological data to develop a simplified model of the magmatic plumbing system of Mount Spurr. The major components of this model are a deep magma source zone at 20--40 km depth, a smaller storage zone at about 10 km depth, and a pipe-like conduit that extends to the surface. The frequency-magnitude distribution of earthquakes measured by the b-value is determined as a function of space beneath Soufriere Hills Volcano, from data recorded between August 1, 1995 and March 31, 1996. A volume of high b-values (b > 3.0) with a 1.5 Ian radius is imaged between 0 and 1.5 Ian beneath English's Crater and Chance's Peak. This anomaly extends southwest to Gage's Soufriere. At depths greater than 2.5 km, volumes of comparatively low b-values ( b ˜ 1) are found beneath St. George's Hill, Windy Hill, and below 2.5 kin to the south of English's Crater.

  1. Volcanoes: Nature's Caldrons Challenge Geochemists.

    ERIC Educational Resources Information Center

    Zurer, Pamela S.

    1984-01-01

    Reviews various topics and research studies on the geology of volcanoes. Areas examined include volcanoes and weather, plate margins, origins of magma, magma evolution, United States Geological Survey (USGS) volcano hazards program, USGS volcano observatories, volcanic gases, potassium-argon dating activities, and volcano monitoring strategies.

  2. Volcanoes: Nature's Caldrons Challenge Geochemists.

    ERIC Educational Resources Information Center

    Zurer, Pamela S.

    1984-01-01

    Reviews various topics and research studies on the geology of volcanoes. Areas examined include volcanoes and weather, plate margins, origins of magma, magma evolution, United States Geological Survey (USGS) volcano hazards program, USGS volcano observatories, volcanic gases, potassium-argon dating activities, and volcano monitoring strategies.…

  3. A Compilation of Gas Emission-Rate Data from Volcanoes of Cook Inlet (Spurr, Crater Peak, Redoubt, Iliamna, and Augustine) and Alaska Peninsula (Douglas, Fourpeaked, Griggs, Mageik, Martin, Peulik, Ukinrek Maars, and Veniaminof), Alaska, from 1995-2006

    USGS Publications Warehouse

    Doukas, Michael P.; McGee, Kenneth A.

    2007-01-01

    INTRODUCTION This report presents gas emission rates from data collected during numerous airborne plume-measurement flights at Alaskan volcanoes since 1995. These flights began in about 1990 as means to establish baseline values of volcanic gas emissions during periods of quiescence and to identify anomalous levels of degassing that might signal the beginning of unrest. The primary goal was to make systematic measurements at the major volcanic centers around the Cook Inlet on at least an annual basis, and more frequently during periods of unrest and eruption. A secondary goal was to measure emissions at selected volcanoes on the Alaska Peninsula. While the goals were not necessarily met in all cases due to weather, funding, or the availability of suitable aircraft, a rich dataset of quality measurements is the legacy of this continuing effort. An earlier report (Doukas, 1995) presented data for the period from 1990 through 1994 and the current report provides data through 2006. This report contains all of the available measurements for SO2, CO2, and H2S emission rates in Alaska determined by the U. S. Geological Survey from 1995 through 2006; airborne measurements for H2S began in Alaska in 2001. The results presented here are from Cook Inlet volcanoes at Spurr, Crater Peak, Redoubt, Iliamna, and Augustine and cover periods of unrest at Iliamna (1996) and Spurr (2004-2006) as well as the 2006 eruption of Augustine. Additional sporadic measurements at volcanoes on the Alaska Peninsula (Douglas, Martin, Mageik, Griggs, Veniaminof, Ukinrek Maars, Peulik, and Fourpeaked during its 2006 unrest) are also reported here.

  4. Monitoring changes in seismic velocity related to an ongoing rapid inflation event at Okmok volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Bennington, Ninfa L.; Haney, Matthew; De Angelis, Silvio; Thurber, Clifford H.; Freymueller, Jeffrey

    2015-08-01

    Okmok is one of the most active volcanoes in the Aleutian Arc. In an effort to improve our ability to detect precursory activity leading to eruption at Okmok, we monitor a recent, and possibly ongoing, GPS-inferred rapid inflation event at the volcano using ambient noise interferometry (ANI). Applying this method, we identify changes in seismic velocity outside of Okmok's caldera, which are related to the hydrologic cycle. Within the caldera, we observe decreases in seismic velocity that are associated with the GPS-inferred rapid inflation event. We also determine temporal changes in waveform decorrelation and show a continual increase in decorrelation rate over the time associated with the rapid inflation event. The magnitude of relative velocity decreases and decorrelation rate increases are comparable to previous studies at Piton de la Fournaise that associate such changes with increased production of volatiles and/or magmatic intrusion within the magma reservoir and associated opening of fractures and/or fissures. Notably, the largest decrease in relative velocity occurs along the intrastation path passing nearest to the center of the caldera. This observation, along with equal amplitude relative velocity decreases revealed via analysis of intracaldera autocorrelations, suggests that the inflation source may be located approximately within the center of the caldera and represent recharge of shallow magma storage in this location. Importantly, there is a relative absence of seismicity associated with this and previous rapid inflation events at Okmok. Thus, these ANI results are the first seismic evidence of such rapid inflation at the volcano.

  5. Post-2008 Inflation of Okmok Volcano, Alaska, from InSAR

    NASA Astrophysics Data System (ADS)

    Lu, Z.; QU, F.; Dzurisin, D.; Kim, J.

    2014-12-01

    Okmok Volcano, a dominantly basaltic volcanic complex that occupies most of the northeastern end of Umnak Island, is among the most active volcanoes in the Aleutian arc (Lu and Dzurisin, 2014). Minor ash eruptions were reported a dozen times since the 1930s. Blocky basalt flows were extruded during dominantly effusive eruptions in 1945, 1958, and 1997, together with minor amounts of ash. From the 1930s to 1997, all of Okmok's eruptions originated from Cone A within the summit caldera. The most recent eruption at Okmok during July-August 2008 was by far the largest and most explosive eruption since at least the early 19th century. The eruption issued from a new vent in the northeast part of the caldera near Cone D, about 5 km northeast of Cone A. The eruption was strongly hydrovolcanic in nature and produced a new tuff cone roughly 240 m high, dramatically altering the landscape inside the caldera. Interferometric synthetic aperture radar (InSAR) observations suggest that a magma reservoir, probably an interconnected network of magma bodies of varying sizes located beneath the caldera and centered ~3 km BSL, was responsible for volcano-wide deformation during 1992-2008, including the 1997 and 2008 eruptions (Lu and Dzurisin, 2014). The reservoir inflated at a variable rate before the 1997 and 2008 eruptions, and withdrawal of magma during both eruptions depressurized the reservoir, causing rapid volcano-wide subsidence. In this study, we report re-inflation of the Okmok reservoir from 2008 to 2014. InSAR imagery from X-band TerraSAR-X, C-band Envisat and L-band ALOS PALSAR satellites indicate that Okmok started inflating soon after the end of 2008 eruption at a rate of 5-10 cm/year, which is confirmed by GPS measurements. Deformation modeling suggests the inflation source is located beneath the center of Okmok caldera at ~3 km BSL, which is essentially the same location responsible for uplift and subsidence during 1992-2008. Lu, Z., and Dzurisin, D., 2014. "InSAR Imaging of Aleutian Volcanoes: Monitoring a Volcanic Arc from Space", Springer Praxis Books, Geophysical Sciences, ISBN 978-3-642-00347-9, 390 pp.

  6. Gas emissions from failed and actual eruptions from Cook Inlet Volcanoes, Alaska, 1989-2006

    USGS Publications Warehouse

    Werner, C.A.; Doukas, M.P.; Kelly, P.J.

    2011-01-01

    Cook Inlet volcanoes that experienced an eruption between 1989 and 2006 had mean gas emission rates that were roughly an order of magnitude higher than at volcanoes where unrest stalled. For the six events studied, mean emission rates for eruptions were ~13,000 t/d CO2 and 5200 t/d SO2, but only ~1200 t/d CO2 and 500 t/d SO2 for non-eruptive events (‘failed eruptions’). Statistical analysis suggests degassing thresholds for eruption on the order of 1500 and 1000 t/d for CO2 and SO2, respectively. Emission rates greater than 4000 and 2000 t/d for CO2 and SO2, respectively, almost exclusively resulted during eruptive events (the only exception being two measurements at Fourpeaked). While this analysis could suggest that unerupted magmas have lower pre-eruptive volatile contents, we favor the explanations that either the amount of magma feeding actual eruptions is larger than that driving failed eruptions, or that magmas from failed eruptions experience less decompression such that the majority of H2O remains dissolved and thus insufficient permeability is produced to release the trapped volatile phase (or both). In the majority of unrest and eruption sequences, increases in CO2 emission relative to SO2 emission were observed early in the sequence. With time, all events converged to a common molar value of C/S between 0.5 and 2. These geochemical trends argue for roughly similar decompression histories until shallow levels are reached beneath the edifice (i.e., from 20–35 to ~4–6 km) and perhaps roughly similar initial volatile contents in all cases. Early elevated CO2 levels that we find at these high-latitude, andesitic arc volcanoes have also been observed at mid-latitude, relatively snow-free, basaltic volcanoes such as Stromboli and Etna. Typically such patterns are attributed to injection and decompression of deep (CO2-rich) magma into a shallower chamber and open system degassing prior to eruption. Here we argue that the C/S trends probably represent tapping of vapor-saturated regions with high C/S, and then gradual degassing of remaining dissolved volatiles as the magma progresses toward the surface. At these volcanoes, however, C/S is often accentuated due to early preferential scrubbing of sulfur gases. The range of equilibrium degassing is consistent with the bulk degassing of a magma with initial CO2 and S of 0.6 and 0.2 wt.%, respectively, similar to what has been suggested for primitive Redoubt magmas.

  7. Gas emissions from failed and actual eruptions from Cook Inlet Volcanoes, Alaska, 1989-2006

    NASA Astrophysics Data System (ADS)

    Werner, Cynthia A.; Doukas, Mike P.; Kelly, Peter J.

    2011-03-01

    Cook Inlet volcanoes that experienced an eruption between 1989 and 2006 had mean gas emission rates that were roughly an order of magnitude higher than at volcanoes where unrest stalled. For the six events studied, mean emission rates for eruptions were 13,000 t/d CO2 and 5200 t/d SO2, but only 1200 t/d CO2 and 500 t/d SO2 for non-eruptive events (`failed eruptions'). Statistical analysis suggests degassing thresholds for eruption on the order of 1500 and 1000 t/d for CO2 and SO2, respectively. Emission rates greater than 4000 and 2000 t/d for CO2 and SO2, respectively, almost exclusively resulted during eruptive events (the only exception being two measurements at Fourpeaked). While this analysis could suggest that unerupted magmas have lower pre-eruptive volatile contents, we favor the explanations that either the amount of magma feeding actual eruptions is larger than that driving failed eruptions, or that magmas from failed eruptions experience less decompression such that the majority of H2O remains dissolved and thus insufficient permeability is produced to release the trapped volatile phase (or both). In the majority of unrest and eruption sequences, increases in CO2 emission relative to SO2 emission were observed early in the sequence. With time, all events converged to a common molar value of C/S between 0.5 and 2. These geochemical trends argue for roughly similar decompression histories until shallow levels are reached beneath the edifice (i.e., from 20-35 to 4-6 km) and perhaps roughly similar initial volatile contents in all cases. Early elevated CO2 levels that we find at these high-latitude, andesitic arc volcanoes have also been observed at mid-latitude, relatively snow-free, basaltic volcanoes such as Stromboli and Etna. Typically such patterns are attributed to injection and decompression of deep (CO2-rich) magma into a shallower chamber and open system degassing prior to eruption. Here we argue that the C/S trends probably represent tapping of vapor-saturated regions with high C/S, and then gradual degassing of remaining dissolved volatiles as the magma progresses toward the surface. At these volcanoes, however, C/S is often accentuated due to early preferential scrubbing of sulfur gases. The range of equilibrium degassing is consistent with the bulk degassing of a magma with initial CO2 and S of 0.6 and 0.2 wt.%, respectively, similar to what has been suggested for primitive Redoubt magmas.

  8. The 7-8 August 2008 eruption of Kasatochi Volcano, central Aleutian Islands, Alaska

    NASA Astrophysics Data System (ADS)

    Waythomas, Christopher F.; Scott, William E.; Prejean, Stephanie G.; Schneider, David J.; Izbekov, Pavel; Nye, Christopher J.

    2010-12-01

    Kasatochi volcano in the central Aleutian Islands erupted unexpectedly on 7-8 August 2008. Kasatochi has received little study by volcanologists and has had no confirmed historical eruptions. The island is an important nesting area for seabirds and a long-term biological study site of the U.S. Fish and Wildlife Service. After a notably energetic preeruptive earthquake swarm, the volcano erupted violently in a series of explosive events beginning in the early afternoon of 7 August. Each event produced ash-gas plumes that reached 14-18 km above sea level. The volcanic plume contained large amounts of SO2 and was tracked around the globe by satellite observations. The cumulative volcanic cloud interfered with air travel across the North Pacific, causing many flight cancelations that affected thousands of travelers. Visits to the volcano in 2008-2009 indicated that the eruption generated pyroclastic flows and surges that swept all flanks of the island, accumulated several tens of meters of pyroclastic debris, and increased the diameter of the island by about 800 m. Pyroclastic flow deposits contain abundant accidental lithic debris derived from the inner walls of the Kasatochi crater. Juvenile material is crystal-rich silicic andesite that ranges from slightly pumiceous to frothy pumice. Fine-grained pyroclastic surge and fall deposits with accretionary lapilli cover the lithic-rich pyroclastic flow deposits and mark a change in eruptive style from episodic explosive activity to more continuous ash emission with smaller intermittent explosions. Pyroclastic deposits completely cover the island, but wave erosion and gully development on the flanks have begun to modify the surface mantle of volcanic deposits.

  9. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 2000 through December 31, 2001

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Moran, Seth C.; Paskievitch, John; McNutt, Stephen R.

    2002-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog reflects the status and evolution of the seismic monitoring program, and presents the basic seismic data for the time period January 1, 2000, through December 31, 2001. For an interpretation of these data and previously recorded data, the reader should refer to several recent articles on volcano related seismicity on Alaskan volcanoes in Appendix G. The AVO seismic network was used to monitor twenty-three volcanoes in real time in 2000-2001. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). AVO located 1551 and 1428 earthquakes in 2000 and 2001, respectively, on and around these volcanoes. Highlights of the catalog period (Table 1) include: volcanogenic seismic swarms at Shishaldin Volcano between January and February 2000 and between May and June 2000; an eruption at Mount Cleveland between February and May 2001; episodes of possible tremor at Makushin Volcano starting March 2001 and continuing through 2001, and two earthquake swarms at Great Sitkin Volcano in 2001. This catalog includes: (1) earthquake origin times, hypocenters, and magnitudes with summary statistics describing the earthquake location quality; (2) a description of instruments deployed in the field and their locations; (3) a description of earthquake detection, recording, analysis, and data archival systems; (4) station parameters and velocity models used for earthquake locations; (5) a summary of daily station usage throughout the catalog period; and (6) all HYPOELLIPSE files used to determine the earthquake locations presented in this report.

  10. Post-eruptive inflation of Okmok Volcano, Alaska, from InSAR, 2008–2014

    USGS Publications Warehouse

    Qu, Feifei; Lu, Zhong; Poland, Michael; Freymueller, Jeffrey T.; Zhang, Qin; Jung, Hyung-Sup

    2016-01-01

    Okmok, a ~10-km wide caldera that occupies most of the northeastern end of Umnak Island, is one of the most active volcanoes in the Aleutian arc. The most recent eruption at Okmok during July-August 2008 was by far its largest and most explosive since at least the early 19th century. We investigate post-eruptive magma supply and storage at the volcano during 2008–2014 by analyzing all available synthetic aperture radar (SAR) images of Okmok acquired during that time period using the multi-temporal InSAR technique. Data from the C-band Envisat and X-band TerraSAR-X satellites indicate that Okmok started inflating very soon after the end of 2008 eruption at a time-variable rate of 48-130 mm/y, consistent with GPS measurements. The “model-assisted” phase unwrapping method is applied to improve the phase unwrapping operation for long temporal baseline pairs. The InSAR time-series is used as input for deformation source modeling, which suggests magma accumulating at variable rates in a shallow storage zone at ~3.9 km below sea level beneath the summit caldera, consistent with previous studies. The modeled volume accumulation in the 6 years following the 2008 eruption is ~75% of the 1997 eruption volume and ~25% of the 2008 eruption volume.

  11. August 2008 eruption of Kasatochi volcano, Aleutian Islands, Alaska-resetting an Island Landscape

    USGS Publications Warehouse

    Scott, W.E.; Nye, C.J.; Waythomas, C.F.; Neal, C.A.

    2010-01-01

    Kasatochi Island, the subaerial portion of a small volcano in the western Aleutian volcanic arc, erupted on 7-8 August 2008. Pyroclastic flows and surges swept the island repeatedly and buried most of it and the near-shore zone in decimeters to tens of meters of deposits. Several key seabird rookeries in taluses were rendered useless. The eruption lasted for about 24 hours and included two initial explosive pulses and pauses over a 6-hr period that produced ash-poor eruption clouds, a 10-hr period of continuous ash-rich emissions initiated by an explosive pulse and punctuated by two others, and a final 8-hr period of waning ash emissions. The deposits of the eruption include a basal muddy tephra that probably reflects initial eruptions through the shallow crater lake, a sequence of pumiceous and lithic-rich pyroclastic deposits produced by flow, surge, and fall processes during a period of energetic explosive eruption, and a fine-grained upper mantle of pyroclastic-fall and -surge deposits that probably reflects the waning eruptive stage as lake and ground water again gained access to the erupting magma. An eruption with similar impact on the island's environment had not occurred for at least several centuries. Since the 2008 eruption, the volcano has remained quiet other than emission of volcanic gases. Erosion and deposition are rapidly altering slopes and beaches. ?? 2010 Regents of the University of Colorado.

  12. A tectonic earthquake sequence preceding the April-May 1999 eruption of Shishaldin Volcano, Alaska

    USGS Publications Warehouse

    Moran, S.C.; Stihler, S.D.; Power, J.A.

    2002-01-01

    On 4 March 1999, a shallow ML 5.2 earthquake occurred beneath Unimak Island in the Aleutian Arc. This earthquake was located 10-15 km west of Shishaldin Volcano, a large, frequently active basaltic-andesite stratovolcano. A Strombolian eruption began at Shishaldin roughly 1 month after the mainshock, culminating in a large explosive eruption on 19 April. We address the question of whether or not the eruption caused the mainshock by computing the Coulomb stress change caused by an inflating dike on fault planes oriented parallel to the mainshock focal mechanism. We found Coulomb stress increases of ???0.1 MPa in the region of the mainshock, suggesting that magma intrusion prior to the eruption could have caused the mainshock. Satellite and seismic data indicate that magma was moving upwards beneath Shishaldin well before the mainshock. indicating that, in an overall sense, the mainshock cannot be said to have caused the eruption. However, observations of changes at the volcano following the mainshock and several large aftershocks suggest that the earthquakes may, in turn, have influenced the course of the eruption.

  13. Mapping recent lava flows at Westdahl Volcano, Alaska, using radar and optical satellite imagery

    USGS Publications Warehouse

    Lu, Zhiming; Rykhus, Russ; Masterlark, Timothy; Dean, K.G.

    2004-01-01

    Field mapping of young lava flows at Aleutian volcanoes is logistically difficult, and the utility of optical images from aircraft or satellites for this purpose is greatly reduced by persistent cloud cover. These factors have hampered earlier estimates of the areas and volumes of three young lava flows at Westdahl Volcano, including its most recent (1991-1992) flow. We combined information from synthetic aperture radar (SAR) images with multispectral Landsat-7 data to differentiate the 1991-1992 flow from the 1964 flow and a pre-1964 flow, and to calculate the flow areas (8.4, 9.2, and 7.3 km 2, respectively). By differencing a digital elevation model (DEM) from the 1970-1980s with a DEM from the Shuttle Radar Topography Mission (SRTM) in February 2000, we estimated the average thickness of the 1991-1992 flow to be 13 m, which reasonably agrees with field observations (5-10 m). Lava-flow maps produced in this way can be used to facilitate field mapping and flow-hazards assessment, and to study magma-supply dynamics and thus to anticipate future eruptive activity. Based on the recurrence interval of recent eruptions and the results of this study, the next eruption at Westdahl may occur before the end of this decade. ?? 2004 Elsevier Inc. All rights reserved.

  14. Glacier Destruction and Lahar Generation during the 2009 Eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.

    2010-12-01

    Two large lahars with volumes of 0.4-0.6 km3 and several smaller lahars with volumes of 0.05-0.1 km3 inundated the Drift River valley on the north flank of Redoubt Volcano during its 2009 eruption. Significant lahars were produced on March 22-23 during the initial explosive phase of the eruption following about 8 months of precursory unrest that included increased fumarolic melting of glacier ice and snow in the summit crater and upper Drift glacier. From the beginning of unrest in late July 2008 through March 20, 2009 about 3-7 x 106 m3 of glacier ice and snow were lost from upper Drift glacier as a result of fumarolic emissions and associated melting. Water and debris outflow during this period was minor and posed no downstream flow hazard beyond the base of the volcano. On March 22-23, explosive eruptions from a summit crater vent destroyed a significant amount of ice in upper Drift glacier and produced a funnel-shaped explosion crater within the larger summit crater. Glacier ice, 50-100 m thick, in the gorge below the vent was stripped to bedrock by pyroclastic flows and melt water. By the next available clear views of the volcano on March 26, about 0.5-1.0 x 108 m3 of ice had been removed from upper Drift glacier including part of the ice field in the summit crater. Melt water liberated by eruptive activity on March 22-23 also eroded or removed most of the river ice and snowpack present in the Drift River valley which may have added an additional 0.1-0.2 km3 of water to the lahars produced during that time. Additional explosions from March 26-April 4 caused further melting of Drift glacier and produced small lahars, but the extent of ice loss and lahar inundation during this period could not be determined because clouds obscured the volcano and much of the Drift River valley. The final explosive event and lahar of the eruption occurred on April 4 when pyroclastic flows produced by lava dome collapse swept over upper Drift glacier and a portion of its piedmont lobe. This event removed about 0.5-1.0 x 108 m3 of glacier ice and initiated a lahar, just slightly larger than the March 22-23 lahar, that inundated an area of about 125 km2 in the Drift River valley from the piedmont lobe to the Cook Inlet coastline about 35 km distant. Pre-eruptive Drift glacier ice volume was about 1 km3 and the total ice removed by the 2009 eruption was 0.1-0.2 km3 or about 10-20% of the total. The total amount of Drift glacier ice removed during the 1989-90 eruption was about 0.1 km3, roughly half of that removed during the 2009 eruption. The largest and most energetic event of the 1989-90 Redoubt eruption on January 2, 1990 removed about 0.25 x 108 m3 of ice from Drift glacier and initiated a lahar of about 0.2 km3, the largest of that eruption. Both the March 22-23 and April 4, 2009 events resulted in greater ice loss and larger lahars than did the January 2, 1990 event. The upper part of Drift glacier is narrow and confined by steep valley walls that restrict the lateral spreading of pyroclastic debris generated by lava dome collapse. This enhances the efficiency of ice melt by funneling pyroclastic flows over the glacier and mechanical erosion and thermal interaction leads to the production of large volumes of melt water and correspondingly large lahars downstream.

  15. Wet deposition of tephra: constraints from eruptions of Kasatochi and Redoubt Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Schwaiger, H.; Schneider, D. J.

    2011-12-01

    The removal of airborne volcanic ash and the deposition onto the ground surface is a result of several mechanisms, including sedimentation, dry deposition, washout and rainout. The last two terms refer to the wet removal from in-cloud scavenging and below-cloud scavenging, respectively. Ash dispersion models are used to forecast the movement of volcanic ash clouds and provide guidance for warning messages to aviation. However, these models often only consider sedimentation, and thus may significantly over-predict the residence time of very fine ash particles (<30 μm). Since explosive silicic eruptions can produce large proportions (30 - >50%) of very fine ash, neglecting wet deposition effects can lead to errors in the prediction of ash dispersal and fallout. Wet deposition of particular aerosols can be parameterized using scavenging coefficients that are a function of the precipitation rate. Wet deposition of volcanic ash is complicated by the large range of particle sizes in a typical ash cloud. Our approach to this problem is to parameterize wet deposition by incorporating variations in particle size into the expression for the scavenging coefficient in an ash dispersion model, Ash3d. Using published observations of wet scavenging of fine particles, we compare model predictions assuming various ash and rain drop size distributions. We test our parameterization scheme using ash-loading calculations from satellite observations of ash plumes generated by the 2008 eruption of Kasatochi volcano and satellite, ground-based radar, and ash fallout observations of the 2009 eruption of Redoubt Volcano. Initial results show that our model agrees well with scavenging observations for particle sizes > 1μm.

  16. Geodetic Measurements and Numerical Modeling of the Deformation Cycle for Okmok Volcano, Alaska: 1993-2008

    NASA Astrophysics Data System (ADS)

    Ohlendorf, S. J.; Feigl, K.; Thurber, C. H.; Lu, Z.; Masterlark, T.

    2011-12-01

    Okmok Volcano is an active caldera located on Umnak Island in the Aleutian Island arc. Okmok, having recently erupted in 1997 and 2008, is well suited for multidisciplinary studies of magma migration and storage because it hosts a good seismic network and has been the subject of synthetic aperture radar (SAR) images that span the recent eruption cycle. Interferometric SAR can characterize surface deformation in space and time, while data from the seismic network provides important information about the interior processes and structure of the volcano. We conduct a complete time series analysis of deformation of Okmok with images collected by the ERS and Envisat satellites on more than 100 distinct epochs between 1993 and 2008. We look for changes in inter-eruption inflation rates, which may indicate inelastic rheologic effects. For the time series analysis, we analyze the gradient of phase directly, without unwrapping, using the General Inversion of Phase Technique (GIPhT) [Feigl and Thurber, 2009]. This approach accounts for orbital and atmospheric effects and provides realistic estimates of the uncertainties of the model parameters. We consider several models for the source, including the prolate spheroid model and the Mogi model, to explain the observed deformation. Using a medium that is a homogeneous half space, we estimate the source depth to be centered at about 4 km below sea level, consistent with the findings of Masterlark et al. [2010]. As in several other geodetic studies, we find the source to be approximately centered beneath the caldera. To account for rheologic complexity, we next apply the Finite Element Method to simulate a pressurized cavity embedded in a medium with material properties derived from body wave seismic tomography. This approach allows us to address the problem of unreasonably large pressure values implied by a Mogi source with a radius of about 1 km by experimenting with larger sources. We also compare the time dependence of the source to published results that used GPS data.

  17. Catalog of earthquake hypocenters at Alaskan Volcanoes: January 1 through December 31, 2010

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Searcy, Cheryl K.

    2011-01-01

    Between January 1 and December 31, 2010, the Alaska Volcano Observatory (AVO) located 3,405 earthquakes, of which 2,846 occurred within 20 kilometers of the 33 volcanoes with seismograph subnetworks. There was no significant seismic activity in 2010 at these monitored volcanic centers. Seismograph subnetworks with severe outages in 2009 were repaired in 2010 resulting in three volcanic centers (Aniakchak, Korovin, and Veniaminof) being relisted in the formal list of monitored volcanoes. This catalog includes locations and statistics of the earthquakes located in 2010 with the station parameters, velocity models, and other files used to locate these earthquakes.

  18. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2002

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sánchez, John; Estes, Steve; McNutt, Stephen R.; Paskievitch, John

    2003-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001; Dixon and others, 2002). The primary objectives of this program are the seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the basic seismic data and changes in the seismic monitoring program for the period January 1, 2002 through December 31, 2002. Appendix G contains a list of publications pertaining to seismicity of Alaskan volcanoes based on these and previously recorded data. The AVO seismic network was used to monitor twenty-four volcanoes in real time in 2002. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). Monitoring highlights in 2002 include an earthquake swarm at Great Sitkin Volcano in May-June; an earthquake swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and long-period events at Mount Veniaminof in September-October and in December; and continuing volcanogenic seismic swarms at Shishaldin Volcano throughout the year. Instrumentation and data acquisition highlights in 2002 were the installation of a subnetwork on Okmok Volcano, the establishment of telemetry for the Mount Veniaminof subnetwork, and the change in the data acquisition system to an EARTHWORM detection system. AVO located 7430 earthquakes during 2002 in the vicinity of the monitored volcanoes. This catalog includes: (1) a description of instruments deployed in the field and their locations; (2) a description of earthquake detection, recording, analysis, and data archival systems; (3) a description of velocity models used for earthquake locations; (4) a summary of earthquakes located in 2002; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, and location quality statistics; daily station usage statistics; and all HYPOELLIPSE files used to determine the earthquake locations in 2002.

  19. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2003

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sanchez, John J.; McNutt, Stephen R.; Estes, Steve; Paskievitch, John

    2004-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of this program are the near real time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the calculated earthquake hypocenter and phase arrival data, and changes in the seismic monitoring program for the period January 1 through December 31, 2003. The AVO seismograph network was used to monitor the seismic activity at twenty-seven volcanoes within Alaska in 2003. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai volcanic cluster (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Okmok Caldera, Great Sitkin Volcano, Kanaga Volcano, Tanaga Volcano, and Mount Gareloi. Monitoring highlights in 2003 include: continuing elevated seismicity at Mount Veniaminof in January-April (volcanic unrest began in August 2002), volcanogenic seismic swarms at Shishaldin Volcano throughout the year, and low-level tremor at Okmok Caldera throughout the year. Instrumentation and data acquisition highlights in 2003 were the installation of subnetworks on Tanaga and Gareloi Islands, the installation of broadband installations on Akutan Volcano and Okmok Caldera, and the establishment of telemetry for the Okmok Caldera subnetwork. AVO located 3911 earthquakes in 2003. This catalog includes: (1) a description of instruments deployed in the field and their locations; (2) a description of earthquake detection, recording, analysis, and data archival systems; (3) a description of velocity models used for earthquake locations; (4) a summary of earthquakes located in 2003; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, and location quality statistics; daily station usage statistics; and all HYPOELLIPSE files used to determine the earthquake locations in 2003.

  20. A space-borne, multi-parameter, Virtual Volcano Observatory for the real-time, anywhere-anytime support to decision-making during eruptive crises

    NASA Astrophysics Data System (ADS)

    Ferrucci, F.; Tampellini, M.; Loughlin, S. C.; Tait, S.; Theys, N.; Valks, P.; Hirn, B.

    2013-12-01

    The EVOSS consortium of academic, industrial and institutional partners in Europe and Africa, has created a satellite-based volcano observatory, designed to support crisis management within the Global Monitoring for Environment and Security (GMES) framework of the European Commission. Data from 8 different payloads orbiting on 14 satellite platforms (SEVIRI on-board MSG-1, -2 and -3, MODIS on-board Terra and Aqua, GOME-2 and IASI onboard MetOp-A, OMI on-board Aura, Cosmo-SkyMED/1, /2, /3 and /4, JAMI on-board MTSAT-1 and -2, and, until April 8th2012, SCHIAMACHY on-board ENVISAT) acquired at 5 different down-link stations, are disseminated to and automatically processed at 6 locations in 4 countries. The results are sent, in four separate geographic data streams (high-temperature thermal anomalies, volcanic Sulfur dioxide daily fluxes, volcanic ash and ground deformation), to a central facility called VVO, the 'Virtual Volcano Observatory'. This system operates 24H/24-7D/7 since September 2011 on all volcanoes in Europe, Africa, the Lesser Antilles, and the oceans around them, and during this interval has detected, measured and monitored all subaerial eruptions occurred in this region (44 over 45 certified, with overall detection and processing efficiency of ~97%). EVOSS borne realtime information is delivered to a group of 14 qualified end users, bearing the direct or indirect responsibility of monitoring and managing volcano emergencies, and of advising governments in Comoros, DR Congo, Djibouti, Ethiopia, Montserrat, Uganda, Tanzania, France and Iceland. We present the full set of eruptions detected and monitored - from 2004 to present - by multispectral payloads SEVIRI onboard the geostationary platforms of the MSG constellation, for developing and fine tuning-up the EVOSS system along with its real-time, pre- and post-processing automated algorithms. The set includes 91% of subaerial eruptions occurred at 15 volcanoes (Piton de la Fournaise, Karthala, Jebel al Tair, Erta Ale, Manda Hararo, Dalafilla, Nabro, Ol Doinyo Lengai, Nyiamulagira, Nyiragongo, Etna, Stromboli, Eyjafjallajökull, Grimsvötn, Soufriere Hills) showing radiant fluxes above ~0.5 GW and/or SO2 columns in excess of ~6 DU. Porting of automated thermal algorithms on MTSAT's JAMI (orbiting at 145°E) was developed on the eruptions of Merapi, Semeru Kliuchevskoi, Bezymianny and Shiveluch in 2006-2007, calibrated on the frequent activity of Batu Tara, and demonstrated on the 2012-2013 large eruption of Tolbachik.

  1. Evidence for Magmatic Intrusion at Mount Spurr Volcano, Alaska, from GPS measurements.

    NASA Astrophysics Data System (ADS)

    Cervelli, P. F.; Coombs, M. L.; Freymueller, J. T.; McGee, K. A.

    2005-12-01

    Mount Spurr is a 3400-m high ice- and snow-covered andesitic stratovolcano located ~105 km east of Anchorage, Alaska, USA. Two historical eruptions (1953 and 1992) have occurred. Both were sub-Plinian (VEI 4), the eruption columns reaching ~20 km above sea level, and both deposited several mm of ash over south-central Alaska. In July, 2004, the micro-seismicity rate at Mount Spurr rose markedly. At about the same time, a melt pit appeared at Spurr's summit. Airborne gas measurements, begun in August 2004, showed abnormally high CO2 flux (~1000 tonnes/day). A plausible interpretation of this unrest is the intrusion of magma at some depth beneath Mount Spurr. As volatiles began to exsolve from the intrusion, they rose into the edifice, raising pore fluid pressure and triggering the increased seismicity. The rising volatiles carried heat convectively to the surface, melting the ice and snow at the summit. In an effort to image the hypothesized magmatic intrusion, three telemetered, continuous Global Positioning System (GPS) receivers were deployed on the flanks of Mount Spurr in September, 2004. Four campaign monuments were also established and then re-occupied in June, 2005. For terrain and logistical reasons, the stations are located predominantly to the south of the summit, though one campaign station does lie slightly to the northwest. Benchmark instability is a concern in this region of alpine permafrost. One station in particular shows evidence of seasonal down-slope creep. We calculated station velocities from the GPS measurements, correcting for obvious benchmark instability where possible. The velocity field stands out prominently from the background regional signal. The southern stations, including all three continuous instruments, show a radial pattern of motion, with the center roughly coincident with Spurr's summit, with a maximum horizontal velocity of 3 to 4 cm/yr. However, the northwest campaign station shows little or no motion, making it inconsistent with the radial pattern of the other stations. We interpret the velocity field as arising from magmatic intrusion, especially in light of the other geophysical measurements and geologic observations, which support the same conclusion. The asymmetric character of the velocity field suggests either a geometrically complex source or the existence of active structures within the edifice that distort an otherwise radial magmatic signal. We explore both possibilities, though the relatively small number of geophysical data points and the poorly known structural geology of the area pose a serious non-uniqueness problem. Provided that the basic interpretation of magmatic intrusion is correct, the magnitude of the velocities suggests an intrusive rate on the order of 107 m3 per year.

  2. Estimating lava volume by precision combination of multiple baseline spaceborne and airborne interferometric synthetic aperture radar: The 1997 eruption of Okmok Volcano, Alaska

    USGS Publications Warehouse

    Lu, Zhiming; Fielding, E.; Patrick, M.R.; Trautwein, C.M.

    2003-01-01

    Interferometric synthetic aperture radar (InSAR) techniques are used to calculate the volume of extrusion at Okmok volcano, Alaska by constructing precise digital elevation models (DEMs) that represent volcano topography before and after the 1997 eruption. The posteruption DEM is generated using airborne topographic synthetic aperture radar (TOPSAR) data where a three-dimensional affine transformation is used to account for the misalignments between different DEM patches. The preeruption DEM is produced using repeat-pass European Remote Sensing satellite data; multiple interferograms are combined to reduce errors due to atmospheric variations, and deformation rates are estimated independently and removed from the interferograms used for DEM generation. The extrusive flow volume associated with the 1997 eruption of Okmok volcano is 0.154 ?? 0.025 km3. The thickest portion is approximately 50 m, although field measurements of the flow margin's height do not exceed 20 m. The in situ measurements at lava edges are not representative of the total thickness, and precise DEM data are absolutely essential to calculate eruption volume based on lava thickness estimations. This study is an example that demonstrates how InSAR will play a significant role in studying volcanoes in remote areas.

  3. Chemical versus temporal controls on the evolution of tholeiitic and calc-alkaline magmas at two volcanoes in the Alaska-Aleutian arc

    USGS Publications Warehouse

    George, R.; Turner, S.; Hawkesworth, C.; Bacon, C.R.; Nye, C.; Stelling, P.; Dreher, S.

    2004-01-01

    The Alaska-Aleutian island arc is well known for erupting both tholeiitic and calc-alkaline magmas. To investigate the relative roles of chemical and temporal controls in generating these contrasting liquid lines of descent we have undertaken a detailed study of tholeiitic lavas from Akutan volcano in the oceanic A1eutian arc and calc-alkaline products from Aniakchak volcano on the continental A1askan Peninsula. The differences do not appear to be linked to parental magma composition. The Akutan lavas can be explained by closed-system magmatic evolution, whereas curvilinear trace element trends and a large range in 87 Sr/86 Sr isotope ratios in the Aniakchak data appear to require the combined effects of fractional crystallization, assimilation and magma mixing. Both magmatic suites preserve a similar range in 226 Ra-230 Th disequilibria, which suggests that the time scale of crustal residence of magmas beneath both these volcanoes was similar, and of the order of several thousand years. This is consistent with numerical estimates of the time scales for crystallization caused by cooling in convecting crustal magma chambers. During that time interval the tholeiitic Akutan magmas underwent restricted, closed-system, compositional evolution. In contrast, the calc-alkaline magmas beneath Aniakchak volcano underwent significant open-system compositional evolution. Combining these results with data from other studies we suggest that differentiation is faster in calc-alkaline and potassic magma series than in tholeiitic series, owing to a combination of greater extents of assimilation, magma mixing and cooling.

  4. Precursory swarms of long-period events at Redoubt Volcano (1989 1990), Alaska: Their origin and use as a forecasting tool

    NASA Astrophysics Data System (ADS)

    Chouet, Bernard A.; Page, Robert A.; Stephens, Christopher D.; Lahr, John C.; Power, John A.

    1994-08-01

    During the eruption of Redoubt Volcano from December 1989 through April 1990, the Alaska Volcano Observatory issued advance warnings of several tephra eruptions based on changes in seismic activity related to the occurrence of precursory swarms of long-period (LP) seismic events (dominant period of about 0.5 s). The initial eruption on December 14 occurred after 23 years of quiescence and was heralded by a 23-hour swarm of LP events that ended abruptly with the eruption. After a series of vent-clearing explosions over the next few days, dome growth began on December 21. Another swarm, with LP events similar to those of the first, began on the 26th and ended in a major tephra eruption on January 2. Eruptions continued over the next two weeks and then ceased until February 15, when a large eruption initiated a long phase of repetitive dome-building and dome-destroying episodes that continued into April. Warnings were issued before the major events on December 14 and January 2, but as the eruptive sequence continued after January 2, the energy of the swarms decreased and forecasting became more difficult. A significant but less intense swarm preceded the February 15 eruption, which was not forecast. This eruption destroyed the only seismograph on the volcanic edifice and stymied forecasting until March 4, when the first of three new stations was installed within 3 km of the active vent. From March 4 to the end of the sequence on April 21, there were eight eruptions, six of which were preceded by detectable swarms of LP events. Although weak, these swarms provided the basis for warnings issued before the eruptions on March 23 and April 6. The initial swarm on December 13 had the following features: (1) short duration (23 hours); (2) a rapidly accelerating rate of seismic energy release over the first 18 hours of the swarm, followed by a decline of activity during the 5 hours preceding the eruption; (3) a magnitude range from -0.4 to 1.6; (4) nearly identical LP signatures with a dominant period near 0.5 s; (5) dilatational first motions everywhere; and (6) a stationary source location at a depth of 1.4 km beneath the crater. This occurrence of long-period events suggests a model involving the interaction of magma with groundwater in which magmatic gases, steam and water drive a fixed conduit at a stationary point throughout the swarm. The initiation of that sequence of events is analogous to the failure of a pressure-relief valve connecting a lower, supercharged magma-dominated reservoir to a shallow hydrothermal system. A three-dimensional model of a vibrating fluid-filled crack recently developed by Chouet is found to be compatible with the seismic data and yields the following parameters for the LP source: crack length, 280-380 m; crack width, 140-190 m; crack thickness, 0.05-0.20 m; crack stiffness, 100-200; sound speed of fluid, 0.8-1.3 km/s; compressional-wave speed of rock, 5.1 km/s; density ratio of fluid to rock, ≈0.4; and ratio of bulk modulus of fluid to rigidity of rock, 0.03-0.07. The fluid-filled crack is excited intermittently by an impulsive pressure drop that varies in magnitude within the range of 0.4 to 40 bar. Such disturbance appears to be consistent with a triggering mechanism associated with choked flow conditions in the crack.

  5. UNIT, ALASKA.

    ERIC Educational Resources Information Center

    Louisiana Arts and Science Center, Baton Rouge.

    THE UNIT DESCRIBED IN THIS BOOKLET DEALS WITH THE GEOGRAPHY OF ALASKA. THE UNIT IS PRESENTED IN OUTLINE FORM. THE FIRST SECTION DEALS PRINCIPALLY WITH THE PHYSICAL GEOGRAPHY OF ALASKA. DISCUSSED ARE (1) THE SIZE, (2) THE MAJOR LAND REGIONS, (3) THE MOUNTAINS, VOLCANOES, GLACIERS, AND RIVERS, (4) THE NATURAL RESOURCES, AND (5) THE CLIMATE. THE…

  6. Stable-isotope evidence for a magmatic component in fumarole condensates from Augustine Volcano, Cook Inlet, Alaska, U.S.A.

    USGS Publications Warehouse

    Viglino, J.A.; Harmon, R.S.; Borthwick, J.; Nehring, N.L.; Motyka, R.J.; White, L.D.; Johnston, D.A.

    1985-01-01

    D/H and 18O 16O ratios have been determined for fumarole condensates from Augustine Volcano, an active calc-alkaline stratovolcano in Lower Cook Inlet, Alaska. The isotopic data for the condensates form a linear ?? D-?? 18O array from low-temperature fluids (450??C) fluids collected at the volcano summit which are enriched in both D and 18O (?? D {reversed tilde equals} -35???, ?? 18O {reversed tilde equals} +3.5???). Several lines of evidence suggest that the D-and 18O-rich condensates likely are "magmatic" fluids released into the hydrothermal system during and immediately after the 1976 eruption. Prior to 1976, the Augustine hydrothermal system was dominated completely by local meteoric waters. Between 1976 and 1982, fumarole condensates were observed to be variable mixtures of the "magmatic" fluid and meteoric water, with the proportion of the former systematically decreasing as the hydrothermal system cooled following the 1976 eruption. ?? 1985.

  7. Improving attenuation tomography by novel inversions for t* and Q: application to Parkfield, California and Okmok volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Pesicek, J. D.; Bennington, N. L.; Thurber, C. H.; Zhang, H.

    2011-12-01

    Standard methods for mapping variations in seismic attenuation (Q) structure using local earthquake data involve a two-step process. First, values of the whole path attenuation operator t* are determined from earthquake data recorded on a seismic array by inverting observed spectra for source and attenuation parameters. Then, these t* data are used to invert tomographically for frequency-independent Q models. The observed earthquake amplitude spectra depend on both source parameters and site effects. However, quantification of site effects is often neglected. Bennington et al. [2008] determined site response jointly with source parameters for small groups of events and then computed each station's site response as the average over all groups. Building on this work, we have adapted the method to model all events simultaneously to more accurately determine site response from the earthquake spectra. This in turn allows us to more accurately determine t*. However, resolution analysis of the results shows that some parameters are not well resolved in the joint inversion. Thus, an alternating inversion scheme is tested and adapted to alleviate poor resolution and parameter trade-offs. The new scheme produces better fits to the earthquake spectra than previous methods, and the resulting t* data should allow for more accurate determination of the Q structure. Because the equation relating t* to Q is nonlinear, the typical approach to determining Q is to solve for changes to a starting model iteratively, similar to methods commonly used in travel time tomography. However, if we instead solve for the inverse of Q, the equation becomes linear and the solution no longer depends on the starting model. This simple modification may allow us to more accurately determine Q. We test these new t* and Q methods using earthquake data from Parkfield, California and Okmok volcano, Alaska. We present the results for real and synthetic data and compare and contrast these results to more traditional inversion techniques to illustrate enhancements to the Q models.

  8. Amphibole reaction rim textures and mineralogy from the 2006 eruption of Augustine Volcano, Alaska: Nature vs. experiment

    NASA Astrophysics Data System (ADS)

    Henton, S.; Larsen, J. F.; Coombs, M. L.

    2011-12-01

    Augustine Volcano forms a small island located in Alaska's Cook Inlet, approximately 180 miles southwest of Anchorage. The 2006 eruption began January 11, 2006, and evolved from an initial phase of explosive activity, through continuous and effusive phases, ending approximately mid-March 2006. We present data on the textural and mineralogical make-up of amphibole reaction rims from 2006 andesites from Augustine. Naturally formed reaction rims are compared to rims formed through decompression and heating experiments. Amphiboles make up less than 1 modal % of most samples. However, variations in composition and texture help to explain pre-and syn-eruptive magma histories. The Augustine 2006 amphiboles contain a mixture of rimmed and unrimmed grains. In order of decreasing abundance (by tally), the dominant phases in reaction rims are orthopyroxene, oxides, plagioclase, and clinopyroxene. Most amphibole reaction rims are between 1- 40 microns in thickness. Thicker rims (> 40 microns) were primarily erupted in the later effusive phase of the eruption. In general, the thickest reactions rims (> 60 microns average thickness) contain coarser individual reaction rim grains (with feret diameters of 15-50 microns). Reaction rims with average thickness of less than 60 microns tend to contain finer reaction rim grains (with feret diameters of 10 microns or less). Some reactions rims show a coarsening of rim grains across the rim, from the amphibole boundary to the glass boundary. Preliminary results show no systematic changes in the aspect ratios of reaction rim grains, either across the rim, or between the different rims. Some rims show a decrease in the An content of plagioclase across the rim, from the amphibole boundary to the glass boundary. Reaction rim textures and mineralogy are complex and suggest that multiple forcing factors (including heating and decompression) were responsible for their formation. This study will compare these natural reaction rims to those formed in experiments.

  9. Preliminary assessment for the use of VORIS as a tool for rapid lava flow simulation at Goma Volcano Observatory, Democratic Republic of the Congo

    NASA Astrophysics Data System (ADS)

    Syavulisembo, A. M.; Havenith, H.-B.; Smets, B.; d'Oreye, N.; Marti, J.

    2015-10-01

    Assessment and management of volcanic risk are important scientific, economic, and political issues, especially in densely populated areas threatened by volcanoes. The Virunga volcanic province in the Democratic Republic of the Congo, with over 1 million inhabitants, has to cope permanently with the threat posed by the active Nyamulagira and Nyiragongo volcanoes. During the past century, Nyamulagira erupted at intervals of 1-4 years - mostly in the form of lava flows - at least 30 times. Its summit and flank eruptions lasted for periods of a few days up to more than 2 years, and produced lava flows sometimes reaching distances of over 20 km from the volcano. Though most of the lava flows did not reach urban areas, only impacting the forests of the endangered Virunga National Park, some of them related to distal flank eruptions affected villages and roads. In order to identify a useful tool for lava flow hazard assessment at Goma Volcano Observatory (GVO), we tested VORIS 2.0.1 (Felpeto et al., 2007), a freely available software (http://www.gvb-csic.es) based on a probabilistic model that considers topography as the main parameter controlling the lava flow propagation. We tested different parameters and digital elevation models (DEM) - SRTM1, SRTM3, and ASTER GDEM - to evaluate the sensitivity of the models to changes in input parameters of VORIS 2.0.1. Simulations were tested against the known lava flows and topography from the 2010 Nyamulagira eruption. The results obtained show that VORIS 2.0.1 is a quick, easy-to-use tool for simulating lava-flow eruptions and replicates to a high degree of accuracy the eruptions tested when input parameters are appropriately chosen. In practice, these results will be used by GVO to calibrate VORIS for lava flow path forecasting during new eruptions, hence contributing to a better volcanic crisis management.

  10. Dante's Volcano

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

  11. Dante's volcano

    NASA Astrophysics Data System (ADS)

    1994-09-01

    This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

  12. The Alaska Lake Ice and Snow Observatory Network (ALISON): Hands-on Experiential K- 12 Learning in the North

    NASA Astrophysics Data System (ADS)

    Morris, K.; Jeffries, M.

    2008-12-01

    The Alaska Lake Ice and Snow Observatory Network (ALISON) was initiated by Martin Jeffries (UAF polar scientist), Delena Norris-Tull (UAF education professor) and Ron Reihl (middle school science teacher, Fairbanks North Star Borough School District). The snow and ice measurement protocols were developed in 1999-2000 at the Poker Flat Research Range (PFRR) by Geophysical Institute, University of Alaska scientists and tested by home school teacher/students in winter 2001-2002 in Fairbanks, AK. The project was launched in 2002 with seven sites around the state (PFRR, Fairbanks, Barrow, Mystic Lake, Nome, Shageluk and Wasilla). The project reached its broadest distribution in 2005-2006 with 22 sites. The schools range from urban (Wasilla) to primarily Alaska native villages (Shageluk). They include public schools, charter schools, home schooled students and parents, informal educators and citizen scientists. The grade levels range from upper elementary to high school. Well over a thousand students have participated in ALISON since its inception. Equipment is provided to the observers at each site. Measurements include ice thickness (with a hot wire ice thickness gauge), snow depth and snow temperature (surface and base). Snow samples are taken and snow density derived. Snow variables are used to calculate the conductive heat flux through the ice and snow cover to the atmosphere. All data are available on the Web site. The students and teachers are scientific partners in the study of lake ice processes, contributing to new scientific knowledge and understanding while also learning science by doing science with familiar and abundant materials. Each autumn, scientists visit each location to work with the teachers and students, helping them to set up the study site, showing them how to make the measurements and enter the data into the computer, and discussing snow, ice and polar environmental change. A number of 'veteran' teachers are now setting up the study sites on their own. Each summer, a workshop in Fairbanks offers the teachers the opportunity to work and learn together, sharing their ALISON field experiences and transfer to the classroom, testing activities and materials, and adding to their content knowledge. This experiential learning project demonstrates that teachers and students can make scientifically valuable measurements when provided with easy-to-use equipment, clear directions and training. The project also shows that when provided with a stimulating learning opportunity, teachers and students find imaginative ways to extend the experience. For example, a number of students have made videos about their ALISON. Lesson plans using ALISON-related science concepts have been generated by ALISON teachers and others. Several ALISON teachers have published articles about the ALISON experience. ALISON teachers have been awarded prestigious Toyota Tapestry grants in support of their activities.

  13. Hydrothermal activity and carbon-dioxide discharge at Shrub and upper Klawasi mud volcanoes, Wrangell Mountains, Alaska

    USGS Publications Warehouse

    Sorey, Michael L.; Werner, Cindy; McGimsey, Robert G.; Evans, William C.

    2000-01-01

    Shrub mud volcano, one of three mud volcanoes of the Klawasi group in the Copper River Basin, Alaska, has been discharging warm mud and water and CO2?rich gas since 1996. A field visit to Shrub in June 1999 found the general level of hot-spring discharge to be similar, but somewhat more widespread, than in the previous two years. Evidence of recent animal and vegetation deaths from CO2 exposure were confined to localized areas around various gas and fluid vents. Maximum fluid temperatures in each of three main discharge areas, ranging from 48-54?C, were equal to or higher than those measured in the two previous years; such temperatures are significantly higher than those observed intermittently over the past 30 years. At Upper Klawasi mud volcano, measured temperatures of 23-26?C and estimated rates of gas and water discharge in the summit crater lake were also similar to those observed in the previous two years. Gas discharging at Shrub and Upper Klawasi is composed of over 98% CO2 and minor amounts of meteoric gases (N2, O2, Ar) and gases partly of deeper origin (CH4 and He). The rate of CO2 discharge from spring vents and pools at Shrub is estimated to be ~10 metric tonnes per day. This discharge, together with measured concentrations of bicarbonate, suggest that a total CO2 upflow from depth of 20-40 metric tonnes per day at Shrub.Measurements were made of diffuse degassing rates from soil at one ~300 m2 area near the summit of Shrub that included vegetation kill suggestive of high CO2 concentrations in the root zone. Most of measured gas flow rates in this area were significantly higher than background values, and a CO2 concentration of 26 percent was measured at a depth of 10 cm where the gas flow rate was highest. Although additional measurements of diffuse gas flow were made elsewhere at Shrub, no other areas of vegetation kill related to diffuse degassing and high soil-gas CO2 concentrations could be seen from the air.Chemical and isotopic compositions of the gas and water discharging at Shrub and Upper Klawasi indicate derivation from a combination of mantle (magmatic) and crustal (marine sedimentary rock) sources and suggest a common fluid reservoir at depth. In particular, both the total dissolved carbon and values of 13C in CO2 are similar for fluids and gas sampled at each area, and do not appear to have changed with the onset of increased spring temperatures and fluid discharge at Shrub. This suggests that the underlying cause of the recent changes in discharge rate and temperature at Shrub is not an increase in the rate of input of magmatic heat and volatiles, but rather increases in the permeability of the upflow conduits that connect the gas-rich reservoir to the surface.

  14. 2005 Crater Lake Formation, Lahar, Acidic Flood, and Gas Emission From Chiginagak Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Schaefer, J. R.; Scott, W. E.; McGimsey, R. G.; Jorgenson, J.

    2005-12-01

    A 400-m-wide crater lake developed in the formerly snow-and-ice-filled crater of Mount Chiginagak volcano sometime between August 2004 and June 2005, presumably due to increased heat flux from the hydrothermal system. We are also evaluating the possible role of magma intrusion and degassing. In early summer 2005, clay-rich debris and an estimated 5.6 million cubic meters of acidic water from the crater exited through tunnels in the base of a glacier that breaches the south crater rim. Over 27 kilometers downstream, the acidic waters of the flood reached approximately 1.5 meters above current water levels and inundated an important salmon spawning drainage, acidifying at least the surface water of Mother Goose Lake (approximately 1 cubic kilometer in volume) and preventing the annual salmon run. No measurements of pH were taken until late August 2005. At that time the pH of water sampled from the Mother Goose Lake inlet, lake surface, and outlet stream (King Salmon River) was 3.2. Defoliation and leaf damage of vegetation along affected streams, in areas to heights of over 70 meters in elevation above flood level, indicates that a cloud of detrimental gas or aerosol accompanied the flood waters. Analysis of stream water, lake water, and vegetation samples is underway to better determine the agent responsible for the plant damage. This intriguing pattern of gas-damaged vegetation concentrated along and above the flood channels is cause for further investigation into potential hazards associated with Chiginagak's active crater lake. Anecdotal evidence from local lodge owners and aerial photographs from 1953 suggest that similar releases occurred in the mid-1970s and early 1950s.

  15. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this spectacular MODIS image from November 7, 2001, the skies are clear over Alaska, revealing winter's advance. Perhaps the most interesting feature of the image is in its center; in blue against the rugged white backdrop of the Alaska Range, Denali, or Mt. McKinley, casts its massive shadow in the fading daylight. At 20,322 ft (6,194m), Denali is the highest point in North America. South of Denali, Cook Inlet appears flooded with sediment, turning the waters a muddy brown. To the east, where the Chugach Mountains meet the Gulf of Alaska, and to the west, across the Aleutian Range of the Alaska Peninsula, the bright blue and green swirls indicate populations of microscopic marine plants called phytoplankton. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  16. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this spectacular MODIS image from November 7, 2001, the skies are clear over Alaska, revealing winter's advance. Perhaps the most interesting feature of the image is in its center; in blue against the rugged white backdrop of the Alaska Range, Denali, or Mt. McKinley, casts its massive shadow in the fading daylight. At 20,322 ft (6,194m), Denali is the highest point in North America. South of Denali, Cook Inlet appears flooded with sediment, turning the waters a muddy brown. To the east, where the Chugach Mountains meet the Gulf of Alaska, and to the west, across the Aleutian Range of the Alaska Peninsula, the bright blue and green swirls indicate populations of microscopic marine plants called phytoplankton.

  17. Preliminary Seismic, Infrasound and Lightning Observations of the July 2008 Eruptions of Okmok Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    McNutt, S. R.; Arnoult, K. M.; Szuberla, C. A.; Stihler, S. D.

    2008-12-01

    Okmok volcano began to erupt July 12, 2008, following an 11 year hiatus. The previous eruption in 1997 was from Cone A whereas the new activity occurred on the north flank of Cone D, a structure that had not been active for 800 years. Seismic activity at Okmok is monitored by a network of eight short-period and four broadband seismometers. The eruption was preceded by a swarm of earthquakes lasting just 5 hours, with events large enough to be located only occurring in the last hour. The bulk of these events occurred under Cone D with a few near Cone A. The eruption began with the onset of continuous tremor at 19:43 UT, which increased abruptly at 19:48 UT and lasted about 12 hours, strongest at about 22:00 UT. The tremor was strong enough to appear on stations out to 260 km distance. The ash cloud quickly grew to an elevation of 16 km or more. Infrasonic waves from the eruption were recorded on the I53US infrasound array in Fairbanks as three groups of waves starting at 21:44 UT, 01:14 UT July 13, and 05:41 UT July 13 and lasting 29-95 minutes. The time of flight is estimated to be 94 minutes along a great circle path. The waves were strongest between 0.1 and 0.5 Hz and had amplitudes of 0.1-0.3 Pa at the array. Low-pass filtered broadband seismic data showed extremely long-period waves with a period of 540 sec starting at about 22:45 UT. However, these waves, which were also visible in GOES satellite images and are thought to be gravity waves, have not yet been found in the infrasound data. Vigorous lightning was observed in the eruption column by observers at Fort Glenn, 12 km from the vent, on July 12 and several occasions after that. Unfortunately no instrumental data were obtained for the lightning.

  18. SAR-based Estimation of Glacial Extent and Velocity Fields on Isanotski Volcano, Aleutian Islands, Alaska

    NASA Astrophysics Data System (ADS)

    Sousa, D.; Lee, A.; Parker, O. P.; Pressler, Y.; Guo, S.; Osmanoglu, B.; Schmidt, C.

    2012-12-01

    Global studies show that Earth's glaciers are losing mass at increasing rates, creating a challenge for communities that rely on them as natural resources. Field observation of glacial environments is limited by cost and inaccessibility. Optical remote sensing is often precluded by cloud cover and seasonal darkness. Synthetic aperture radar (SAR) overcomes these obstacles by using microwave-frequency electromagnetic radiation to provide high resolution information on large spatial scales and in remote, atmospherically obscured environments. SAR is capable of penetrating clouds, operating in darkness, and discriminating between targets with ambiguous spectral signatures. This study evaluated the efficacy of two SAR Earth observation methods on small (< 7 km2) glaciers in rugged topography. The glaciers chosen for this study lie on Isanotski Volcano in Unimak Island, Aleutian Archipelago, USA. The local community on the island, the City of False Pass, relies on glacial melt for drinking water and hydropower. Two methods were used: (1) velocity field estimation based on Repeat Image Feature Tracking (RIFT) and (2) glacial boundary delineation based on interferometric coherence mapping. NASA Uninhabited Aerial Vehicle SAR (UAVSAR) single-polarized power images and JAXA Advanced Land Observing Satellite Phased Array type L-band SAR (ALOS PALSAR) single-look complex images were analyzed over the period 2008-2011. UAVSAR image pairs were coregistered to sub-pixel accuracy and processed with the Coregistration of Optically Sensed Images and Correlation (COSI-Corr) feature tracking module to derive glacial velocity field estimates. Maximum glacier velocities ranged from 28.9 meters/year to 58.3 meters/year. Glacial boundaries were determined from interferometric coherence of ALOS PALSAR data and subsequently refined with masking operations based on terrain slope and segment size. Accuracy was assessed against hand-digitized outlines from high resolution UAVSAR power images, yielding 83.0% producer's accuracy (errors of omission) and 86.1% user's accuracy (errors of commission). These results represent a refinement of a decades-old entry from the USGS National Hydrography Dataset (NHD). The information gained from this study could strengthen management practices by helping decision makers understand the ecological and economic consequences of glacial change. This procedure could be repeated in similar locations worldwide to provide communities with accurate, quantitative information about their changing glacial resources.

  19. The 1992 eruptions of Crater Peak vent, Mount Spurr Volcano, Alaska

    USGS Publications Warehouse

    Keith, Terry E.C.

    1995-01-01

    Sulfur dioxide scrubbing by liquid water masked SO2 emissions from shallow magma during the 1992 eruptions of Crater Peak and effectively prevented observation of SO2 emissions from shallow magma both before and after explosive eruptions and seismic crises. Airborne ultraviolet correlation spectrometer (COSPEC) measurements from July 22, 1991, to September 24, 1992, indicate only background to minor ( H2S(aq) + 3H+(aq) + 3HSO4-(aq). Sulfur dioxide hydrolysis also explains the increase in the sulfate content of Crater Peak lake water prior to the first eruption, the strong H2S odor during periods of background to low SO2 emission, the TOMS evidence for significant H2S emissions during the explosive eruptions, and the observed decline of SO2 during periods of volcanic tremor. Abundant, local sources of melt water and a high permeability for the Mount Spurr volcanic edifice are probably the chief factors responsible for masking SO2 emissions by scrubbing, and possibly for quenching shallow intrusions that were ascending. Large SO2 emissions unencumbered by scrubbing were only possible during the three explosive eruptions when magma penetrated through liquid water zones under Crater Peak and reached the surface. Nonexplosive SO2 emissions of as much as 750 t/d were possible, however, for a brief period when dry pathways to the surface existed from September 25 until about October 10, 1992. Airborne infrared spectrometer (MIRAN) measurements of CO2 emissions indicate that in addition to the degassing of magma through dry pathways, degassing through boiling water with the loss of SO2 by scrubbing was also important during that time. The CO2 emission data indicate that magma degassing was taking place, and CO2/SO2 values calculated from MIRAN and COSPEC data are in the range 10 to 100, which supports the hypothesis of SO2 loss by scrubbing. Because of its strong preference for the vapor phase during boiling, CO2 emissions from degassing magma are less likely to be masked by the presence of water, whereas SO2 emissions may be lost totally from interactions with water; thus misleading COSPEC results are obtained. We recommended prompt and early monitoring of CO2 when Cook Inlet volcanoes become restless.

  20. Lightning associated with the 1992 eruptions of Crater Peak, Mount Spurr Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    McNutt, S. R.; Davis, C. M.

    2000-10-01

    Lightning occurred associated with the ash clouds of all three eruptions of Mt. Spurr Volcano in 1992. Lightning was detected on seismograms as simultaneous spikes and simultaneous gain-ranging (a feature that normally lowers the gain at a station when the signal level begins to saturate). Spikes had typical durations of 0.04-0.05 s. Using uniform criteria we found 28 lightning flashes in the June 27th eruption, 29 in the August 18th eruption, and three in the September 17th eruption. We measured peak voltages on station RSO, 94 km SSW, to determine the relative strengths of lightning, and found that the August lightning was strongest, June weakest, and September intermediate. Based on relative signal strengths at different stations, we found evidence for different lightning geometries between the June and August eruptions, during which prevailing winds blew the ash clouds to the north and east, respectively. For all three eruptions the first lightning was recorded 21-26 min after the onset of the eruption, suggesting that charge separation occurred in the convecting cloud rather than at the vent. Data recorded by a Bureau of Land Management lightning detection system for the August eruption showed negative polarities for the first 12 recorded flashes and a positive polarity for the last. This suggests a charge separation based on particle size, in which negative charge is found for larger particles which fall first, and positive charge remains on smaller particles which remain suspended longer. All three eruptions had similar durations of 3.5-4 h, and tephra volumes of 44-56 million cubic meters. The August eruption, however, produced stronger volcanic tremor, 30 cm 2 reduced displacement as compared with 16 cm 2 for June, and greater gas, 400±120 kt SO 2 for August and 200±60 kt for June. Thus lightning strength correlates with both tremor amplitude and magmatic gas content. The August eruption occurred during the lightest winds, so the ash cloud and charge separation were vertically oriented and favored cloud-to-ground lightning. The September eruption occurred during the coldest and driest atmospheric conditions, which may explain the small amount of lightning. In general, volcanic lightning is important because it can help confirm that explosive eruptions are in progress, although the value of the information may be limited by the long delay from eruption onset to first lightning and the variability of eruptive and atmospheric conditions.

  1. Eruption of Shiveluch Volcano, Kamchatka Peninsula

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On March 29, 2007, the Shiveluch Volcano on the Russian Federation's Kamchatka Peninsula erupted. According to the Alaska Volcano Observatory the volcano underwent an explosive eruption between 01:50 and 2:30 UTC, sending an ash cloud skyward roughly 9,750 meters (32,000 feet), based on visual estimates. The Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard NASA's Aqua satellite took this picture at 02:00 UTC on March 29. The top image shows the volcano and its surroundings. The bottom image shows a close-up view of the volcano at 250 meters per pixel. Satellites often capture images of volcanic ash plumes, but usually as the plumes are blowing away. Plumes have been observed blowing away from Shiveluch before. This image, however, is different. At the time the Aqua satellite passed overhead, the eruption was recent enough (and the air was apparently still enough) that the ash cloud still hovered above the summit. In this image, the bulbous cloud casts its shadow northward over the icy landscape. Volcanic ash eruptions inject particles into Earth's atmosphere. Substantial eruptions of light-reflecting particles can reduce temperatures and even affect atmospheric circulation. Large eruptions impact climate patterns for years. A massive eruption of the Tambora Volcano in Indonesia in 1815, for instance, earned 1816 the nickname 'the year without a summer.' Shiveluch is a stratovolcano--a steep-sloped volcano composed of alternating layers of solidified ash, hardened lava, and volcanic rocks. One of Kamchatka's largest volcanoes, it sports a summit reaching 3,283 meters (10,771 feet). Shiveluch is also one of the peninsula's most active volcanoes, with an estimated 60 substantial eruptions in the past 10,000 years.

  2. Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 through December 31, 2007

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.

    2008-01-01

    Between January 1 and December 31, 2007, AVO located 6,664 earthquakes of which 5,660 occurred within 20 kilometers of the 33 volcanoes monitored by the Alaska Volcano Observatory. Monitoring highlights in 2007 include: the eruption of Pavlof Volcano, volcanic-tectonic earthquake swarms at the Augustine, Illiamna, and Little Sitkin volcanic centers, and the cessation of episodes of unrest at Fourpeaked Mountain, Mount Veniaminof and the northern Atka Island volcanoes (Mount Kliuchef and Korovin Volcano). This catalog includes descriptions of : (1) locations of seismic instrumentation deployed during 2007; (2) earthquake detection, recording, analysis, and data archival systems; (3) seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2007; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, and all files used to determine the earthquake locations in 2007.

  3. Instrumentation Recommendations for Volcano Monitoring at U.S. Volcanoes Under the National Volcano Early Warning System

    USGS Publications Warehouse

    Moran, Seth C.; Freymueller, Jeff T.; LaHusen, Richard G.; McGee, Kenneth A.; Poland, Michael P.; Power, John A.; Schmidt, David A.; Schneider, David J.; Stephens, George; Werner, Cynthia A.; White, Randall A.

    2008-01-01

    As magma moves toward the surface, it interacts with anything in its path: hydrothermal systems, cooling magma bodies from previous eruptions, and (or) the surrounding 'country rock'. Magma also undergoes significant changes in its physical properties as pressure and temperature conditions change along its path. These interactions and changes lead to a range of geophysical and geochemical phenomena. The goal of volcano monitoring is to detect and correctly interpret such phenomena in order to provide early and accurate warnings of impending eruptions. Given the well-documented hazards posed by volcanoes to both ground-based populations (for example, Blong, 1984; Scott, 1989) and aviation (for example, Neal and others, 1997; Miller and Casadevall, 2000), volcano monitoring is critical for public safety and hazard mitigation. Only with adequate monitoring systems in place can volcano observatories provide accurate and timely forecasts and alerts of possible eruptive activity. At most U.S. volcanoes, observatories traditionally have employed a two-component approach to volcano monitoring: (1) install instrumentation sufficient to detect unrest at volcanic systems likely to erupt in the not-too-distant future; and (2) once unrest is detected, install any instrumentation needed for eruption prediction and monitoring. This reactive approach is problematic, however, for two reasons. 1. At many volcanoes, rapid installation of new ground-1. based instruments is difficult or impossible. Factors that complicate rapid response include (a) eruptions that are preceded by short (hours to days) precursory sequences of geophysical and (or) geochemical activity, as occurred at Mount Redoubt (Alaska) in 1989 (24 hours), Anatahan (Mariana Islands) in 2003 (6 hours), and Mount St. Helens (Washington) in 1980 and 2004 (7 and 8 days, respectively); (b) inclement weather conditions, which may prohibit installation of new equipment for days, weeks, or even months, particularly at midlatitude or high-latitude volcanoes; (c) safety factors during unrest, which can limit where new instrumentation can safely be installed (particularly at near-vent sites that can be critical for precursor detection and eruption forecasting); and (d) the remoteness of many U.S. volcanoes (particularly those in the Aleutians and the Marianas Islands), where access is difficult or impossible most of the year. Given these difficulties, it is reasonable to anticipate that ground-based monitoring of eruptions at U.S. volcanoes will likely be performed primarily with instruments installed before unrest begins. 2. Given a growing awareness of previously undetected 2. phenomena that may occur before an eruption begins, at present the types and (or) density of instruments in use at most U.S. volcanoes is insufficient to provide reliable early warning of volcanic eruptions. As shown by the gap analysis of Ewert and others (2005), a number of U.S. volcanoes lack even rudimentary monitoring. At those volcanic systems with monitoring instrumentation in place, only a few types of phenomena can be tracked in near-real time, principally changes in seismicity, deformation, and large-scale changes in thermal flux (through satellite-based remote sensing). Furthermore, researchers employing technologically advanced instrumentation at volcanoes around the world starting in the 1990s have shown that subtle and previously undetectable phenomena can precede or accompany eruptions. Detection of such phenomena would greatly improve the ability of U.S. volcano observatories to provide accurate early warnings of impending eruptions, and is a critical capability particularly at the very high-threat volcanoes identified by Ewert and others (2005). For these two reasons, change from a reactive to a proactive volcano-monitoring strategy is clearly needed at U.S. volcanoes. Monitoring capabilities need to be expanded at virtually every volcanic center, regardless of its current state of

  4. Peninsular terrane basement ages recorded by Paleozoic and Paleoproterozoic zircon in gabbro xenoliths and andesite from Redoubt volcano, Alaska

    USGS Publications Warehouse

    Bacon, Charles R.; Vazquez, Jorge A.; Wooden, Joseph L.

    2012-01-01

    Historically Sactive Redoubt volcano is an Aleutian arc basalt-to-dacite cone constructed upon the Jurassic–Early Tertiary Alaska–Aleutian Range batholith. The batholith intrudes the Peninsular tectonostratigraphic terrane, which is considered to have developed on oceanic basement and to have accreted to North America, possibly in Late Jurassic time. Xenoliths in Redoubt magmas have been thought to be modern cumulate gabbros and fragments of the batholith. However, new sensitive high-resolution ion microprobe (SHRIMP) U-Pb ages for zircon from gabbro xenoliths from a late Pleistocene pyroclastic deposit are dominated by much older, ca. 310 Ma Pennsylvanian and ca. 1865 Ma Paleoproterozoic grains. Zircon age distributions and trace-element concentrations indicate that the ca. 310 Ma zircons date gabbroic intrusive rocks, and the ca. 1865 Ma zircons also are likely from igneous rocks in or beneath Peninsular terrane basement. The trace-element data imply that four of five Cretaceous–Paleocene zircons, and Pennsylvanian low-U, low-Th zircons in one sample, grew from metamorphic or hydrothermal fluids. Textural evidence of xenocrysts and a dominant population of ca. 1865 Ma zircon in juvenile crystal-rich andesite from the same pyroclastic deposit show that this basement has been assimilated by Redoubt magma. Equilibration temperatures and oxygen fugacities indicated by Fe-Ti–oxide minerals in the gabbros and crystal-rich andesite suggest sources near the margins of the Redoubt magmatic system, most likely in the magma accumulation and storage region currently outlined by seismicity and magma petrology at ∼4–10 km below sea level. Additionally, a partially melted gabbro from the 1990 eruption contains zircon with U-Pb ages between ca. 620 Ma and ca. 1705 Ma, as well as one zircon with a U-Th disequilibrium model age of 0 ka. The zircon ages demonstrate that Pennsylvanian, and probably Paleoproterozoic, igneous rocks exist in, or possibly beneath, Peninsular terrane basement. Discovery of Pennsylvanian gabbro similar in age to Skolai arc plutons 500 km to the northeast indicates that the Peninsular terrane, along with the Wrangellia and Alexander terranes, has been part of the Wrangellia composite terrane since at least Pennsylvanian time. Moreover, the zircon data suggest that a Paleoproterozoic continental fragment may be present in the mid-to-upper crust in southern Alaska.

  5. Acoustic measurements of the 1999 basaltic eruption of Shishaldin volcano, Alaska 2. Precursor to the Subplinian phase

    USGS Publications Warehouse

    Vergniolle, S.; Caplan-Auerbach, J.

    2004-01-01

    The 1999 eruption of Shishaldin volcano (Alaska, USA) displayed both Strombolian and Subplinian basaltic activity. The Subplinian phase was preceded by a signal of low amplitude and constant frequency (??? 2 Hz) lasting 13 h. This "humming signal" is interpreted as the coalescence of the very shallow part of a foam building up in the conduit, which produces large gas bubbles before bursting. The acoustic waveform of the hum event is modelled by a Helmholtz resonator: gas is trapped into a rigid cavity and can only escape through a tiny upper hole producing sound waves. At Shishaldin, the radius of the hole (??? 5 m) is close to that of the conduit (??? 6 m), the cavity has a length of ??? 60 m, and gas presents only a small overpressure between (??? 1.2 ?? 10-3 and 4.5 ?? 10-3 MPa). Such an overpressure is obtained by the partial coalescence of a foam formed by bubbles with a diameter from ??? 2.3 mm at the beginning of the episode towards ??? 0.64 mm very close to the end of the phase. The intermittency between hum events is explained by the ripening of the foam induced by the H2O diffusion through the liquid films. The two extreme values, from 600 to 10 s, correspond to a bubble diameter from 2.2 to 0.3 mm at the beginning and end of the pre-Subplinian phase, respectively. The extremely good agreement between two independent estimates of bubble diameters in the shallow foam reinforces the validity of such an interpretation. The total gas volume lost at the surface during the humming events is at most 5.9 ?? 106 m3. At the very end of the pre-Subplinian phase, there is a single large bubble with an overpressure of ???0.42 MPa. The large overpressure suggests that it comes from significant depth, unlike other bubbles in the pre-Subplinian phase. This deep bubble may be responsible for the entire foam collapse, resulting in the Subplinian phase. ?? 2004 Elsevier B.V. All rights reserved.

  6. Paleo-tsunami and Tephrochronologic Investigations into the Late Holocene Volcanic History of Augustine Volcano on the Southwest Coast of the Kenai Peninsula, Lower Cook Inlet Alaska

    NASA Astrophysics Data System (ADS)

    Maharrey, J. Z.; Beget, J. E.; Wallace, K.

    2014-12-01

    Augustine Volcano, a small island volcano located in Cook Inlet, Alaska has produced approximately 11 flank-failure debris-avalanches over the last 2,000 yrs (BP) that were large enough to reach the coast of the island and enter the sea. Each debris avalanche conceivably could have triggered a tsunami. In 1883, a tsunami generated by an eruption and flank-failure of Augustine inundated the indigenous Alaskan village of Nanwalek (previously English Bay) with 8 meters of runup. Nanwalek is geographically located atop a coastal headland on the southwest coast of the Kenai Peninsula approximately 85 kilometers due east of Augustine (Beget et al., 2008). Current research in Nanwalek is focused on describing a peat exposure situated on the shoreward edge of the English Bay headland. We present new data from this locality on the sedimentology, tephrochronology, radiocarbon dating, and field stratigraphy. The exposure is basally dated to approximately 7,100 yr BP and includes exotic units of volcanic ash, sand, and gravel. We correlate 19 tephra layers to late Holocene eruptions of Augustine and several Cook Inlet and northern Alaska Peninsula volcanoes. We interpret the non-volcanic clastic sediment horizons in the peat as prehistoric tsunami-inundation events of the English Bay headland. Augustine volcanic-ash deposits found within the tsunami deposits allow correlation to prehistoric coeval flank-failure debris-avalanche deposits exposed on Augustine (Waitt and Beget, 2009). We correlate three tsunami deposits associated with Augustine tephra marker horizons H, I, and G of Waitt and Beget (2009) each of which were erupted approximately 1,400 yr BP, 1,700 yr BP, and 2,100 yr BP. Additionally, we present new tephra and sedimentological evidence for a 4,100 yr BP paleo-tsunami inundation event at Nanwalek that we correlate to a previously unidentified flank-failure debris-avalanche event at Augustine Volcano. The recognition of this new deposit extends the age record for flank-failure events of Augustine Volcano by approximately 2,000 years.

  7. A geologic evaluation of proposed lava diversion barriers for the NOAA Mauna Loa Observatory, Mauna Loa Volcano, Hawaii

    USGS Publications Warehouse

    Moore, H.J.

    1982-01-01

    Lava flow diversion barriers should protect the Mauna Loa Observatory from flows of reasonable magnitude if properly constructed. The a'a flow upon which the observatory is constructed represents a flow of reasonable magnitude. Proper construction of the barriers includes obtaining riprap from a zone exterior to the proposed V-shaped barrier so as to produce an exterior relief near 9.2 m for most of the barrier, construction of a channel about 8 m deep and 40 m wide along the east part of the barrier, and proper positioning of an isolated initiating barrier. Calculations suggest that the barriers should be able to handle peak volume flow rates near 800 m/s and possibly larger ones. Peak volume flow rates for the a'a flow upon which the observatory is constructed are estimated.

  8. Voluminous ice-rich and water-rich lahars generated during the 2009 eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Waythomas, Christopher F.; Pierson, Thomas C.; Major, Jon J.; Scott, William E.

    2013-06-01

    Redoubt Volcano in south-central Alaska began erupting on March 15, 2009, and by April 4, 2009, had produced at least 20 explosive events that generated multiple plumes of ash and numerous lahars. The 3108-m-high, snow- and ice-clad stratovolcano has an ice-filled summit crater that is breached to the north. The volcano supports about 4 km3 of ice and snow and about 1 km3 of this makes up the Drift glacier on the north side of the volcano. Explosive eruptions between March 23 and April 4, which included the destruction of at least two lava domes, triggered significant lahars in the Drift River valley on March 23 and April 4, and several smaller lahars between March 24 and March 31. Mud-line high-water marks, character of deposits, areas of inundation, and estimates of flow velocity revealed that the lahars on March 23 and April 4 were the largest of the eruption. In the 2-km-wide upper Drift River valley, average flow depths were at least 2-5 m. Average peak-flow velocities were likely between 10 and 15 ms- 1, and peak discharges were on the order of 104-105 m3 s- 1. The area inundated by lahars on March 23 was at least 100 km2 and on April 4 about 125 km2. Two substantial lahars emplaced on March 23 and one on April 4 had volumes on the order of 107-108 m3 and were similar in size to the largest lahar of the 1989-90 eruption. The two principal March 23 lahars were primarily flowing slurries of snow and ice derived from Drift glacier and the Drift River valley where seasonal snow and tabular blocks of river ice were entrained and incorporated into the lahars. Despite morphologic evidence of two lahars, only a single deposit up to 5 m thick was found in most places and it contained about 80-95% of poorly sorted, massive to imbricate assemblages of snow and ice clasts. The deposit was frozen soon after it was emplaced and later eroded and buried by the April 4 lahar. The lahar of April 4, in contrast, was primarily a hyperconcentrated flow, as interpreted from 1- to 6-m-thick deposits of massive to horizontally stratified sand to fine gravel. Rock material in the April 4 lahar deposit is predominantly juvenile andesite, whereas rock material in the March 23 deposit is rare and not obviously juvenile. We infer that the lahars generated on March 23 were initiated by a rapid succession of vent-clearing explosions that blasted through about 50-100 m of crater-filling glacier ice and snow, producing a voluminous release of meltwater from Drift glacier. The resulting surge of water entrained snow, fragments of glacier and river ice, and river water along its flow path. Small-volume pyroclastic flows, possibly associated with destruction of a small dome or minor eruption-column collapses, may have contributed additional meltwater to the March 23 lahars. Meltwater generated by subglacial hydrothermal activity and stored beneath Drift glacier may have been ejected or released rapidly as well. The April 4 lahar was initiated when hot dome-collapse pyroclastic flows entrained and swiftly melted snow and ice on Drift glacier. The resulting meltwater incorporated pyroclastic debris and rock material from Drift glacier to form the largest lahar of the 2009 eruption. The peak discharge of the April 4 lahar was in the range of 60,000-160,000 m3 s- 1. For comparison, the largest lahar of the 1989-90 eruption had a peak discharge of about 80,000 m3 s- 1. Lahars generated by the 2009 eruption led to significant channel aggradation in the lower Drift River valley and caused extensive inundation at an oil storage and transfer facility located there. The April 4, 2009, lahar was 6-30 times larger than the largest meteorological floods known or estimated in the Drift River drainage.

  9. Rapid chemical evolution of tropospheric volcanic emissions from Redoubt Volcano, Alaska, based on observations of ozone and halogen-containing gases

    NASA Astrophysics Data System (ADS)

    Kelly, Peter J.; Kern, Christoph; Roberts, Tjarda J.; Lopez, Taryn; Werner, Cynthia; Aiuppa, Alessandro

    2013-06-01

    We report results from an observational and modeling study of reactive chemistry in the tropospheric plume emitted by Redoubt Volcano, Alaska. Our measurements include the first observations of Br and I degassing from an Alaskan volcano, the first study of O3 evolution in a volcanic plume, as well as the first detection of BrO in the plume of a passively degassing Alaskan volcano. This study also represents the first detailed spatially-resolved comparison of measured and modeled O3 depletion in a volcanic plume. The composition of the plume was measured on June 20, 2010 using base-treated filter packs (for F, Cl, Br, I, and S) at the crater rim and by an instrumented fixed-wing aircraft on June 21 and August 19, 2010. The aircraft was used to track the chemical evolution of the plume up to ~ 30 km downwind (2 h plume travel time) from the volcano and was equipped to make in situ observations of O3, water vapor, CO2, SO2, and H2S during both flights plus remote spectroscopic observations of SO2 and BrO on the August 19th flight. The airborne data from June 21 reveal rapid chemical O3 destruction in the plume as well as the strong influence chemical heterogeneity in background air had on plume composition. Spectroscopic retrievals from airborne traverses made under the plume on August 19 show that BrO was present ~ 6 km downwind (20 min plume travel time) and in situ measurements revealed several ppbv of O3 loss near the center of the plume at a similar location downwind. Simulations with the PlumeChem model reproduce the timing and magnitude of the observed O3 deficits and suggest that autocatalytic release of reactive bromine and in-plume formation of BrO were primarily responsible for the observed O3 destruction in the plume. The measurements are therefore in general agreement with recent model studies of reactive halogen formation in volcanic plumes, but also show that field studies must pay close attention to variations in the composition of ambient air entrained into volcanic plumes in order to unambiguously attribute observed O3 anomalies to specific chemical or dynamic processes. Our results suggest that volcanic eruptions in Alaska are sources of reactive halogen species to the subarctic troposphere.

  10. Areal distribution, thickness, mass, volume, and grain size of tephra-fall deposits from the 1992 eruptions of Crater Peak vent, Mt. Spurr Volcano, Alaska

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Riley, Colleen M.

    2001-01-01

    The Crater Peak flank vent of Mount Spurr volcano erupted June 27, August 18, and September 16- 17, 1992. The three eruptions were similar in intensity (vulcanian to subplinian eruption columns reaching up to 14 km Above Sea Level) and duration (3.5 to 4.0 hours) and produced tephra-fall deposits (12, 14, 15 x 10 6 m3 Dense Rock Equivalent [DRE]) discernible up to 1,000 km downwind. The June 27 ash cloud traveled north over the rugged, ice- and snow-covered Alaska Range. The August 18 ash cloud was carried southeastward over Anchorage, across Prince William Sound, and down the southeastern shoreline of the Gulf of Alaska. The September 16-17 ash plume was directed eastward over the Talkeetna and Wrangell mountains and into the Yukon Territory of Canada. Over 50 mass-per-unit-area (MPUA) samples were collected for each of the latter two fall deposits at distances ranging from about 2 km to 370 km downwind from the volcano. Only 10 (mostly proximal) samples were collected for the June fall deposit due to inaccessible terrain and funding constraints. MPUA data were plotted and contoured (isomass lines) to graphically display the distribution of each fall deposit. For the August and September eruptions, fallout was concentrated along a narrow (30 to 50 km wide) belt. The fallout was most concentrated (100,000 to greater than 250,000 g/m2) within about 80 km of the volcano. Secondary maxima occur at 200 km (2,620 g/m2) and 300 km (4,659 g/m2), respectively, down axis for the August and September deposits. The maxima contain bimodal grain size distributions (with peaks at 88.4 and 22.1 microns) indicating aggregation within the ash cloud. Combined tephra-volume for the 1992 Mount Spurr eruptions (41 x 10 6 m3 DRE) is comparable to that (tephra-fall only) of the 1989-90 eruptions of nearby Redoubt volcano (31-49 x 106 m3 DRE).

  11. Monitoring and modeling ice-rock avalanches from ice-capped volcanoes: A case study of frequent large avalanches on Iliamna Volcano, Alaska

    USGS Publications Warehouse

    Huggel, C.; Caplan-Auerbach, J.; Waythomas, C.F.; Wessels, R.L.

    2007-01-01

    Iliamna is an andesitic stratovolcano of the Aleutian arc with regular gas and steam emissions and mantled by several large glaciers. Iliamna Volcano exhibits an unusual combination of frequent and large ice-rock avalanches in the order of 1 ?? 106??m3 to 3 ?? 107??m3 with recent return periods of 2-4??years. We have reconstructed an avalanche event record for the past 45??years that indicates Iliamna avalanches occur at higher frequency at a given magnitude than other mass failures in volcanic and alpine environments. Iliamna Volcano is thus an ideal site to study such mass failures and its relation to volcanic activity. In this study, we present different methods that fit into a concept of (1) long-term monitoring, (2) early warning, and (3) event documentation and analysis of ice-rock avalanches on ice-capped active volcanoes. Long-term monitoring methods include seismic signal analysis, and space-and airborne observations. Landsat and ASTER satellite data was used to study the extent of hydrothermally altered rocks and surface thermal anomalies at the summit region of Iliamna. Subpixel heat source calculation for the summit regions where avalanches initiate yielded temperatures of 307 to 613??K assuming heat source areas of 1000 to 25??m2, respectively, indicating strong convective heat flux processes. Such heat flow causes ice melting conditions and is thus likely to reduce the strength at the base of the glacier. We furthermore demonstrate typical seismic records of Iliamna avalanches with rarely observed precursory signals up to two hours prior to failure, and show how such signals could be used for a multi-stage avalanche warning system in the future. For event analysis and documentation, space- and airborne observations and seismic records in combination with SRTM and ASTER derived terrain data allowed us to reconstruct avalanche dynamics and to identify remarkably similar failure and propagation mechanisms of Iliamna avalanches for the past 45??years. Simple avalanche flow modeling was able to reasonably replicate Iliamna avalanches and can thus be applied for hazard assessments. Hazards at Iliamna Volcano are low due to its remote location; however, we emphasize the transfer potential of the methods presented here to other ice-capped volcanoes with much higher hazards such as those in the Cascades or the Andes. ?? 2007 Elsevier B.V. All rights reserved.

  12. Exploring Geology on the World-Wide Web--Volcanoes and Volcanism.

    ERIC Educational Resources Information Center

    Schimmrich, Steven Henry; Gore, Pamela J. W.

    1996-01-01

    Focuses on sites on the World Wide Web that offer information about volcanoes. Web sites are classified into areas of Global Volcano Information, Volcanoes in Hawaii, Volcanoes in Alaska, Volcanoes in the Cascades, European and Icelandic Volcanoes, Extraterrestrial Volcanism, Volcanic Ash and Weather, and Volcano Resource Directories. Suggestions…

  13. Using Google Maps to Access USGS Volcano Hazards Information

    NASA Astrophysics Data System (ADS)

    Venezky, D. Y.; Snedigar, S.; Guffanti, M.; Bailey, J. E.; Wall, B. G.

    2006-12-01

    The U.S. Geological Survey (USGS) Volcano Hazard Program (VHP) is revising the information architecture of our website to provide data within a geospatial context for emergency managers, educators, landowners in volcanic areas, researchers, and the general public. Using a map-based interface for displaying hazard information provides a synoptic view of volcanic activity along with the ability to quickly ascertain where hazards are in relation to major population and infrastructure centers. At the same time, the map interface provides a gateway for educators and the public to find information about volcanoes in their geographic context. A plethora of data visualization solutions are available that are flexible, customizable, and can be run on individual websites. We are currently using a Google map interface because it can be accessed immediately from a website (a downloadable viewer is not required), and it provides simple features for moving around and zooming within the large map area that encompasses U.S. volcanism. A text interface will also be available. The new VHP website will serve as a portal to information for each volcano the USGS monitors with icons for alert levels and aviation color codes. When a volcano is clicked, a window will provide additional information including links to maps, images, and real-time data, thereby connecting information from individual observatories, the Smithsonian Institution, and our partner universities. In addition to the VHP home page, many observatories and partners have detailed graphical interfaces to data and images that include the activity pages for the Alaska Volcano Observatory, the Smithsonian Google Earth files, and Yellowstone Volcano Observatory pictures and data. Users with varied requests such as raw data, scientific papers, images, or brief overviews expect to be able to quickly access information for their specialized needs. Over the next few years we will be gathering, cleansing, reorganizing, and posting data in multiple formats to meet these needs.

  14. Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 through December 31, 2005

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; McNutt, Stephen R.

    2006-01-01

    Summary: The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Figure 1). The primary objectives of the seismic program are the real-time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents calculated earthquake hypocenters and seismic phase arrival data, and details changes in the seismic monitoring program for the period January 1 through December 31, 2005. The AVO seismograph network was used to monitor the seismic activity at thirty-two volcanoes within Alaska in 2005 (Figure 1). The network was augmented by two new subnetworks to monitor the Semisopochnoi Island volcanoes and Little Sitkin Volcano. Seismicity at these volcanoes was still being studied at the end of 2005 and has not yet been added to the list of permanently monitored volcanoes in the AVO weekly update. Following an extended period of monitoring to determine the background seismicity at the Mount Peulik, Ukinrek Maars, and Korovin Volcano, formal monitoring of these volcanoes began in 2005. AVO located 9,012 earthquakes in 2005. Monitoring highlights in 2005 include: (1) seismicity at Mount Spurr remaining above background, starting in February 2004, through the end of the year and into 2006; (2) an increase in seismicity at Augustine Volcano starting in May 2005, and continuing through the end of the year into 2006; (3) volcanic tremor and seismicity related to low-level strombolian activity at Mount Veniaminof in January to March and September; and (4) a seismic swarm at Tanaga Volcano in October and November. This catalog includes: (1) descriptions and locations of seismic instrumentation deployed in the field in 2005; (2) a description of earthquake detection, recording, analysis, and data archival systems; (3) a description of seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2005; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, and location quality statistics; daily station usage statistics; and all HYPOELLIPSE files used to determine the earthquake locations in 2005.

  15. Significance of a near-source tephra-stratigraphic sequence to the eruptive history of Hayes Volcano, south-central Alaska

    USGS Publications Warehouse

    Wallace, Kristi; Coombs, Michelle L.; Hayden, Leslie A.; Waythomas, Christopher F.

    2014-01-01

    Bluffs along the Hayes River valley, 31 km northeast and 40 km downstream from Hayes Volcano, reveal volcanic deposits that shed new light on its eruptive history. Three thick (>10 cm) and five thin (<10 cm) tephra-fall deposits are dacitic in whole rock composition and contain high proportions of amphibole to pyroxene and minor biotite and broadly correlate to Hayes tephra set H defined by earlier investigators. Two basal ages for the tephra-fall sequence of 3,690±30 and 3,750±30 14C yr B.P. are also consistent with the Hayes tephra set H timeframe. Distinguishing among Hayes tephra set H units is critical because the set is an important time-stratigraphic marker in south-central Alaska and this section provides a new reference section for Hayes tephra set H. Analysis of Fe-Ti oxide grains in the tephras shows promise for identifying individual Hayes deposits. Beneath the dacitic tephra sequence lies an older, poorly sorted tephra (tephra A) that contains dacite and rhyolite lapilli and whose basal age is 4,450±30 14C yr B.P. Immediately below the tephra-fall sequence (Unit III) lies a series of mass-flow deposits that are rich in rhyodacitic clasts (Unit II). Below Unit II and possibly coeval with it, is a 20–30 m thick pumiceous pyroclastic-flow deposit (Unit I) that extends to the valley floor. Here informally named the Hayes River ignimbrite, this deposit contains pumice clasts of rhyolite with quartz, sanidine, plagioclase, and biotite phenocrysts, an assemblage that is unique among known Quaternary volcanic products of Hayes and other Alaskan volcanoes. Units I, II, and tephra A of Unit III represent at least two previously unrecognized eruptions of Hayes Volcano that occurred prior to ~3,700 yr B.P. No compositionally equivalent distal tephra deposits correlative with Hayes Volcano rhyodacites or rhyolites have yet been identified, perhaps indicating that some of these deposits are pre-Holocene, and were largely removed by glacial ice during the last ice age. More field and analytical work is needed to further refine the eruptive history of Hayes Volcano.

  16. GPS monitoring of Hawaiian Volcanoes

    The USGS Hawaiian Volcano Observatory uses a variety of ground- and satellite-based techniques to monitor Hawai‘i’s active volcanoes.  Here, an HVO scientist sets up a portable GPS receiver to track surface changes during an island-wide survey of Hawai‘i’s volcanoes. &n...

  17. Interactive Volcano Studies and Education Using Virtual Globes

    NASA Astrophysics Data System (ADS)

    Dehn, J.; Bailey, J. E.; Webley, P.

    2006-12-01

    Internet-based virtual globe programs such as Google Earth provide a spatial context for visualization of monitoring and geophysical data sets. At the Alaska Volcano Observatory, Google Earth is being used to integrate satellite imagery, modeling of volcanic eruption clouds and seismic data sets to build new monitoring and reporting tools. However, one of the most useful information sources for environmental monitoring is under utilized. Local populations, who have lived near volcanoes for decades are perhaps one of the best gauges for changes in activity. Much of the history of the volcanoes is only recorded through local legend. By utilizing the high level of internet connectivity in Alaska, and the interest of secondary education in environmental science and monitoring, it is proposed to build a network of observation nodes around local schools in Alaska and along the Aleutian Chain. A series of interactive web pages with observations on a volcano's condition, be it glow at night, puffs of ash, discolored snow, earthquakes, sounds, and even current weather conditions can be recorded, and the users will be able to see their reports in near real time. The database will create a KMZ file on the fly for upload into the virtual globe software. Past observations and legends could be entered to help put a volcano's long-term activity in perspective. Beyond the benefit to researchers and emergency managers, students and teachers in the rural areas will be involved in volcano monitoring, and gain an understanding of the processes and hazard mitigation efforts in their community. K-12 students will be exposed to the science, and encouraged to participate in projects at the university. Infrastructure at the university can be used by local teachers to augment their science programs, hopefully encouraging students to continue their education at the university level.

  18. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 1994 through December 31, 1999

    USGS Publications Warehouse

    Jolly, Arthur D.; Stihler, Scott D.; Power, John A.; Lahr, John C.; Paskievitch, John; Tytgat, Guy; Estes, Steve; Lockhart, Andrew B.; Moran, Seth C.; McNutt, Stephen R.; Hammond, William R.

    2001-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska - Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained a seismic monitoring program at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. Between 1994 and 1999, the AVO seismic monitoring program underwent significant changes with networks added at new volcanoes during each summer from 1995 through 1999. The existing network at Katmai –Valley of Ten Thousand Smokes (VTTS) was repaired in 1995, and new networks were installed at Makushin (1996), Akutan (1996), Pavlof (1996), Katmai - south (1996), Aniakchak (1997), Shishaldin (1997), Katmai - north (1998), Westdahl, (1998), Great Sitkin (1999) and Kanaga (1999). These networks added to AVO's existing seismograph networks in the Cook Inlet area and increased the number of AVO seismograph stations from 46 sites and 57 components in 1994 to 121 sites and 155 components in 1999. The 1995–1999 seismic network expansion increased the number of volcanoes monitored in real-time from 4 to 22, including Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Mount Snowy, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin, Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski volcano, Shisaldin Volcano, Fisher Caldera, Westdahl volcano, Akutan volcano, Makushin Volcano, Great Sitkin volcano, and Kanaga Volcano (see Figures 1-15). The network expansion also increased the number of earthquakes located from about 600 per year in1994 and 1995 to about 3000 per year between 1997 and 1999. Highlights of the catalog period include: 1) a large volcanogenic seismic swarm at Akutan volcano in March and April 1996 (Lu and others, 2000); 2) an eruption at Pavlof Volcano in fall 1996 (Garces and others, 2000; McNutt and others, 2000); 3) an earthquake swarm at Iliamna volcano between September and December 1996; 4) an earthquake swarm at Mount Mageik in October 1996 (Jolly and McNutt, 1999); 5) an earthquake swarm located at shallow depth near Strandline Lake; 6) a strong swarm of earthquakes near Becharof Lake; 7) precursory seismicity and an eruption at Shishaldin Volcano in April 1999 that included a 5.2 ML earthquake and aftershock sequence (Moran and others, in press; Thompson and others, in press). The 1996 calendar year is also notable as the seismicity rate was very high, especially in the fall when 3 separate areas (Strandline Lake, Iliamna Volcano, and several of the Katmai volcanoes) experienced high rates of located earthquakes. This catalog covers the period from January 1, 1994, through December 31,1999, and includes: 1) earthquake origin times, hypocenters, and magnitudes with summary statistics describing the earthquake location quality; 2) a description of instruments deployed in the field and their locations and magnifications; 3) a description of earthquake detection, recording, analysis, and data archival; 4) velocity models used for earthquake locations; 5) phase arrival times recorded at individual stations; and 6) a summary of daily station usage from throughout the report period. We have made calculated hypocenters, station locations, system magnifications, velocity models, and phase arrival information available for download via computer network as a compressed Unix tar file.

  19. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2012

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Haney, Matthew M.; Parker, Tom; Searcy, Cheryl; Prejean, Stephanie

    2013-01-01

    Between January 1 and December 31, 2012, the Alaska Volcano Observatory located 4,787 earthquakes, of which 4,211 occurred within 20 kilometers of the 33 volcanoes monitored by a seismograph network. There was significant seismic activity at Iliamna, Kanaga, and Little Sitkin volcanoes in 2012. Instrumentation highlights for this year include the implementation of the Advanced National Seismic System Quake Monitoring System hardware and software in February 2012 and the continuation of the American Recovery and Reinvestment Act work in the summer of 2012. The operational highlight was the removal of Mount Wrangell from the list of monitored volcanoes. This catalog includes hypocenters, magnitudes, and statistics of the earthquakes located in 2012 with the station parameters, velocity models, and other files used to locate these earthquakes.

  20. Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 through December 31, 2008

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.

    2009-01-01

    Between January 1 and December 31, 2008, the Alaska Volcano Observatory (AVO) located 7,097 earthquakes of which 5,318 occurred within 20 kilometers of the 33 volcanoes monitored by the AVO. Monitoring highlights in 2008 include the eruptions of Okmok Caldera, and Kasatochi Volcano, as well as increased unrest at Mount Veniaminof and Redoubt Volcano. This catalog includes descriptions of: (1) locations of seismic instrumentation deployed during 2008; (2) earthquake detection, recording, analysis, and data archival systems; (3) seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2008; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, and all files used to determine the earthquake locations in 2008.

  1. ASTER Observations of 2000-2007 Thermal Features at Pavlof Volcano and Mt. Hague (Emmons Lake Volcanic Center), Alaska

    NASA Astrophysics Data System (ADS)

    Wessels, R. L.; Schneider, D.; Ramsey, M.; Mangan, M. T.

    2007-12-01

    Emmons Lake Volcanic Center (ELVC) is a 15 km by 30 km area of nested calderas, stratovolcanoes, lava domes, hyaloclastite rings, and cinder cones aligned along the arc axis. Pavlof Volcano is the most active volcano along the ELVC, with more than 40 historic eruptions since 1790. The most recent eruption of Pavlof Volcano began in August 2007 after almost 11 years of quiescence. Mount Hague is a prominent intracaldera vent with no known historical eruptions that lies approximately 7 kilometers to the southwest of Pavlof. The southern crater of Mount Hague commonly fluctuates between a crater-filling lake to a dry crater floor with vigorously steaming fumaroles. Mount Hague has another fumarole field on the southeast flank at nearly the same elevation as the crater floor. To better document the behavior of persistent thermal features at these remote volcanoes, we have compiled temperature and dimension data using a seven-year long time series of satellite data. Over 25 daytime and 40 nighttime clear thermal infrared (TIR) images (90 m resolution) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) have recorded variations in the thermal activity at both volcanic vents since July 2000. All cloud-free ASTER TIR observations document persistent low- temperature features at both Pavlof Volcano and Mount Hague during this period. The size and temperature of each thermal feature varies throughout the study period. The data show that the 2518 m summit of Pavlof Volcano is occasionally snow-free in early summer whereas neighboring peaks at lower elevations are still snow-clad. FLIR data acquired near the summit of Pavlof in 2004 show that the majority of warm ground was at 20°C to 40°C. These warm areas commonly persist snow-free into the winter. Temperature variations observed at Mt Hague crater usually correlate to the size of the ephemeral crater lake. As the lake grows, the pixel-integrated ASTER TIR temperature increases. Measurements using higher resolution (15 m) daytime ASTER visible-near infrared (VNIR) images show that the crater lake size varies between 0 to 4.5 hectares each year. Combined field and satellite observations from the last seven years suggest that the changes to the lake size can occur within a few weeks each summer. When the lake is absent, the fumarole temperatures in the crater parallel the fumarole temperatures observed on the southeast flank of Mount Hague. Periods of vigorous steaming from the Hague crater may coincide with periods of little or no water filling the crater. Although the final data processing is ongoing, preliminary results show no correlation between the thermal activity at Pavlof Volcano with the activity at Mount Hague.

  2. Summit crater lake observations, and the location, chemistry, and pH of water samples near Mount Chiginagak volcano, Alaska: 2004-2012

    USGS Publications Warehouse

    Schaefer, Janet R.; Scott, William E.; Evans, William C.; Wang, Bronwen; McGimsey, Robert G.

    2013-01-01

    Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km southsouthwest of King Salmon, Alaska (fig. 1). This small stratovolcano, approximately 8 km in diameter, has erupted through Tertiary to Permian sedimentary and igneous rocks (Detterman and others, 1987). The highest peak is at an elevation of 2,135 m, and the upper ~1,000 m of the volcano are covered with snow and ice. Holocene activity consists of debris avalanches, lahars, and lava flows. Pleistocene pyroclastic flows and block-and-ash flows, interlayered with andesitic lava flows, dominate the edifice rocks on the northern and western flanks. Historical reports of activity are limited and generally describe steaming and smoking (Coats, 1950; Powers, 1958). Proximal tephra collected during recent fieldwork suggests there may have been limited Holocene explosive activity that resulted in localized ash fall. A cluster of fumaroles on the north flank, at an elevation of ~1,750 m, commonly referred to as the north flank fumarole have been emitting gas throughout historical time (location shown in fig. 2). The only other thermal feature at the volcano is the Mother Goose hot springs located at the base of the edifice on the northwestern flank in upper Volcano Creek, at an elevation of ~160 m (fig. 2, near sites H1, H3, and H4). Sometime between November 2004 and May 2005, a ~400-m-wide, 100-m-deep lake developed in the snow- and ice-filled summit crater of the volcano (Schaefer and others, 2008). In early May 2005, an estimated 3 million cubic meters (3106 m3) of sulfurous, clay-rich debris and acidic water exited the crater through tunnels at the base of a glacier that breaches the south crater rim. More than 27 km downstream, these acidic flood waters reached approximately 1.3 m above normal water levels and inundated a fertile, salmon-spawning drainage, acidifying the entire water column of Mother Goose Lake from its surface waters to its maximum depth of 45 m (resulting pH ~2.9), and preventing the annual salmon run in the King Salmon River. A simultaneous release of gas and acidic aerosols from the crater caused widespread vegetation damage along the flow path. Since 2005, we have been monitoring the crater lake water that continues to flow into Mother Goose Lake by collecting surface water samples for major cation and anion analysis, measuring surface-water pH of affected drainages, and photo-documenting the condition of the summit crater lake. This report describes water sampling locations, provides a table of chemistry and pH measurements, and documents the condition of the summit crater between 2004 and 2011. In September 2013, the report was updated with results of water-chemistry samples collected in 2011 and 2012, which were added as an addendum.

  3. Emission rates of sulfur dioxide and carbon dioxide from Redoubt Volcano, Alaska during the 1989-1990 eruptions

    USGS Publications Warehouse

    Casadevall, T.J.; Doukas, M.P.; Neal, C.A.; McGimsey, R.G.; Gardner, C.A.

    1994-01-01

    Airborne measurements of sulfur dioxide emission rates in the gas plume emitted from fumaroles in the summit crater of Redoubt Volcano were started on March 20, 1990 using the COSPEC method. During the latter half of the period of intermittent dome growth and destruction, between March 20 and mid-June 1990, sulfur dioxide emission rates ranged from approximately 1250 to 5850 t/d, rates notably higher than for other convergent-plate boundary volcanoes during periods of active dome growth. Emission rates following the end of dome growth from late June 1990 through May 1991 decreased steadily to less than 75 t/d. The largest mass of sulfur dioxide was released during the period of explosive vent clearing when explosive degassing on December 14-15 injected at least 175,000 ?? 50,000 tonnes of SO2 into the atmosphere. Following the explosive eruptions of December 1989, Redoubt Volcano entered a period of intermittent dome growth from late December 1989 to mid-June 1990 during which Redoubt emitted a total mass of SO2 ranging from 572,000 ?? 90,000 tonnes to 680,000 ?? 90,000 tonnes. From mid-June 1990 through May 1991, the volcano was in a state of posteruption degassing into the troposphere, producing approximately 183,000 ?? 50,000 tonnes of SO2. We estimate that Redoubt Volcano released a minimum mass of sulfur dioxide of approximately 930,000 tonnes. While COSPEC data were not obtained frequently enough to enable their use in eruption prediction, SO2 emission rates clearly indicated a consistent decline in emission rates between March through October 1990 and a continued low level of emission rates through the first half of 1991. Values from consecutive daily measurements of sulfur dioxide emission rates spanning the March 23, 1990 eruption decreased in the three days prior to eruption. That decrease was coincident with a several-fold increase in the frequency of shallow seismic events, suggesting partial sealing of the magma conduit to gas loss that resulted in pressurization of the shallow magma system and an increase in earthquake activity. Unlike the short-term SO2 decrease in March 1990, the long-term decrease of sulfur dioxide emission rates from March 1990 through May 1991 was coincident with low rates of seismic energy release and was interpreted to reflect gradual depressurization of the shallow magma reservoir. The long-term declines in seismic energy release and in SO2 emission rates led AVO scientists to conclude on April 19, 1991 that the potential for further eruptive activity from Redoubt Volcano had diminished, and on this basis, the level of concern color code for the volcano was changed from code yellow (Volcano is restless; earthquake activity is elevated; activity may include extrusion of lava) to code green (Volcano is in its normal 'dormant' state). ?? 1994.

  4. Long Valley Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Hill, David

    2008-01-01

    The ~300-year-old lava on Paoha Island in Mono Lake was produced by the most recent eruption in the Long Valley Caldera area in east-central California. The Long Valley Caldera was formed by a massive volcanic eruption 760,000 years ago. The region is monitored by the Long Valley Observatory (LVO), one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about the Long Valley Caldera region and LVO at http://volcanoes.usgs.gov/lvo.

  5. A Stratigraphic, Granulometric, and Textural Comparison of recent pyroclastic density current deposits exposed at West Island and Burr Point, Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Rath, C. A.; Browne, B. L.

    2011-12-01

    Augustine Volcano (Alaska) is the most active volcano in the eastern Aleutian Islands, with 6 violent eruptions over the past 200 years and at least 12 catastrophic debris-avalanche deposits over the past ~2,000 years. The frequency and destructive nature of these eruptions combined with the proximity of Augustine Volcano to commercial ports and populated areas represents a significant hazard to the Cook Inlet region of Alaska. The focus of this study examines the relationship between debris-avalanche events and the subsequent emplacement of pyroclastic density currents by comparing the stratigraphic, granulometric, and petrographic characteristics of pyroclastic deposits emplaced following the 1883 A.D. Burr Point debris-avalanche and those emplaced following the ~370 14C yr B.P. West Island debris-avalanche. Data from this study combines grain size and componentry analysis of pyroclastic deposits with density, textural, and compositional analysis of juvenile clasts contained in the pyroclastic deposits. The 1883 A.D. Burr Point pyroclastic unit immediately overlies the 1883 debris avalanche deposit and underlies the 1912 Katmai ash. It ranges in thickness from 4 to 48 cm and consists of fine to medium sand-sized particles and coarser fragments of andesite. In places, this unit is normally graded and exhibits cross-bedding. Many of these samples are fines-enriched, with sorting coefficients ranging from -0.1 to 1.9 and median grain size ranging from 0.1 to 2.4 mm. The ~370 14C yr B.P. West Island pyroclastic unit is sandwiched between the underlying West Island debris-avalanche deposit and the overlying 1912 Katmai Ash deposit, and at times a fine-grained gray ash originating from the 1883 eruption. West Island pyroclastic deposit is sand to coarse-sand-sized and either normally graded or massive with sorting coefficients ranging from 0.9 to 2.8 and median grain sizes ranging from 0.4 to 2.6 mm. Some samples display a bimodal distribution of grain sizes, while most display a fines-depleted distribution. Juvenile andesite clasts exist as either subrounded to subangular fragments with abundant vesicles that range in color from white to brown or dense clasts characterized by their porphyritic and glassy texture. Samples from neither eruption correlate in sorting or grain size with distance from the vent. Stratigraphic and granulometric data suggest differences in the manner in which these two pyroclastic density currents traveled and groundmass textures are interpreted as recording differences in how the two magmas ascended and erupted, whereas juvenile Burr Point clasts resemble other lava flows erupted from Augustine Volcano, vesicular and glassy juvenile West Island clasts bear resemblance to clasts derived from so-called "blast-generated" pyroclastic density deposits at Mt. St. Helens in 1980 and Bezymianny in 1956.

  6. A volcanic activity alert-level system for aviation: review of its development and application in Alaska

    USGS Publications Warehouse

    2013-01-01

    An alert-level system for communicating volcano hazard information to the aviation industry was devised by the Alaska Volcano Observatory (AVO) during the 1989–1990 eruption of Redoubt Volcano. The system uses a simple, color-coded ranking that focuses on volcanic ash emissions: Green—normal background; Yellow—signs of unrest; Orange—precursory unrest or minor ash eruption; Red—major ash eruption imminent or underway. The color code has been successfully applied on a regional scale in Alaska for a sustained period. During 2002–2011, elevated color codes were assigned by AVO to 13 volcanoes, eight of which erupted; for that decade, one or more Alaskan volcanoes were at Yellow on 67 % of days and at Orange or Red on 12 % of days. As evidence of its utility, the color code system is integrated into procedures of agencies responsible for air-traffic management and aviation meteorology in Alaska. Furthermore, it is endorsed as a key part of globally coordinated protocols established by the International Civil Aviation Organization to provide warnings of ash hazards to aviation worldwide. The color code and accompanying structured message (called a Volcano Observatory Notice for Aviation) comprise an effective early-warning message system according to the United Nations International Strategy for Disaster Reduction. The aviation color code system currently is used in the United States, Russia, New Zealand, Iceland, and partially in the Philippines, Papua New Guinea, and Indonesia. Although there are some barriers to implementation, with continued education and outreach to Volcano Observatories worldwide, greater use of the aviation color code system is achievable.

  7. Experimental constraints on the P/T conditions of high silica andesite storage preceding the 2006 eruption of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Henton, S.; Larsen, J. F.; Traxler, N.

    2010-12-01

    We present new experimental results to constrain the P/T storage conditions of the high silica andesite (HSA) prior to the 2006 eruption of Augustine Volcano, Alaska. Augustine Volcano forms a small island located in Alaska’s Cook Inlet, approximately 180 miles southwest of Anchorage. The 2006 eruption began January 11, 2006, and evolved from an initial phase of explosive activity, through continuous and effusive phases, ending approximately mid-March 2006. Lithologies erupted indicate pervasive hybridization between high- (HSA; 62.2-63.3 wt. % SiO2) and low-silica andesite (LSA; 56.6-58.7 wt% SiO2). This study focuses on experiments using the HSA as starting material to constrain magma storage conditions, based on amphibole stability. Experiments were conducted between 100-160 MPa and 800-900 °C, utilzing H2O saturated conditions and fO2 of Re-ReO. Both lightly crushed and sintered HSA were used as starting powders, seeded respectively with 5 wt. % amphibole and a mix of 5 wt. % amphibole and 20 wt. % plagioclase. Experiments with sintered starting material tended toward a bimodal distribution of experimental phenocrysts and microlites, whilst experiments of the lightly crushed material are more phenocryst rich. Preliminary results indicate that amphibole is stable at conditions of 120-140 MPa and 820-840 °C. These pressures correspond with depths of approximately 4.6-5.4 km, which are consistent with prior magma storage models for Augustine 1986 and 2006 magmas, as well as amphiboles found in other arc andesites (e.g., Redoubt and Soufriere Hills volcanoes). Experimental amphiboles are magnesio-hornblendes, which is in keeping with the natural HSA amphiboles. Experimental and natural hornblendes are similar in composition, with the main difference being a small FeO enrichment (2-3 wt%) and MgO depletion (1-2wt%) in the experimental grains. Further work will provide a more complete assessment of amphibole stability and composition, and will be applied towards refining the magma storage model for the Augustine 2006 eruption.

  8. Volatile Abundances and Magma Geochemistry of Recent (2006) Through Ancient Eruptions (Less Than 2100 aBP) of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Webster, J. D.; Mandeville, C. W.; Gerard, T.; Goldoff, B.; Coombs, M. L.

    2006-12-01

    Augustine Volcano, Cook Inlet, Alaska, is a subduction-related Aleutian arc volcano located approximately 275 km southwest of Anchorage. During the past 200 years, Augustine volcano has shown explosive eruptive behavior seven times, with the most recent activity occurring in January through March 2006. Its ash and pumice eruptions pose a threat to commercial air traffic, the local fishing industry, and the inhabitants of the region. Following prior investigations on volatile abundances and processes of evolution for magmas associated with the 1976 (Johnston, 1978) and 1986 (Roman et al., 2005) eruptions of Augustine, we have analyzed phenocrysts, matrix glasses, and silicate melt inclusions in andesites formed during 5 pre-historic eruptions (ranging from 2100 to 1000 years in age) as well as the 1986 and recent 2006 eruptions. Outcrops of basaltic units on Augustine are rare, and basaltic melt inclusions are as well, so most melt inclusions studied range from andesitic to rhyolitic compositions. Comparison of the volatile abundances in felsic melt inclusion glasses shows few differences in H2O, CO2, S, and Cl, respectively, between eruptive materials of the pre- historic, 1976 (Johnston, 1978), and 1986 (Roman et al., 2005; our data) events. The magmas associated with these eruptions contained 1.6 to 8.0 wt.% H2O with 0.21 to 0.84 wt.% Cl, 100 to 1800 ppm CO2, and 100 to 400 ppm S. In contrast, preliminary research on rhyodacitic to rhyolitic melt inclusions in a single 2006 andesite sample collected from a lahar deposit indicates they contain somewhat lower H2O contents and higher Cl and S abundances than felsic melt inclusions from prior eruptions, and they exhibit geochemical trends consonant with magma mixing. Relationships involving H2O, CO2, S, and Cl in prehistoric through 1986 melt inclusions are consistent with fluid-saturated magma evolution of andesitic to rhyolitic melt compositions during closed-system ascent. The various batches of magma rose through dikes to depths as shallow as 2.4 to 0.6 km, at which stage the fluid or fluids began to separate from magma. Fluid separation may have generated some of the seismic signals recorded at these depths during pre-2006 volcanic eruptions. We will examine 2006 juvenile material to evaluate whether or not similar processes of magma evolution and ascent were operative. Johnston D.A. (1978) Univ. Washington unpub. Ph.D. dissertation. Roman, D.C., et al. (2005) Bull. Volcanol. 84:240-254.

  9. Geophysical Characterization of Interactions Between Pyroclastic Flows and Snow and Water During the 2006 Eruptions of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Beget, J.

    2006-12-01

    The 2006 eruption of Augustine Volcano provided a unique opportunity to test a new, geophysical approach to describing and characterizing pyroclastic flows (PFs) and their complex interactions with snow and water. Field measurements of volume magnetic susceptibility (K) of the 2006 deposits at Augustine Volcano, made with a Bartington MS2F probe, showed the primary magnetic susceptibility of the pyroclastic deposits was strongly affected by secondary interactions with water and steam. Smaller changes in K occurred where pyroclastic debris was found in mixed avalanche deposits associated with snow. Pyroclastic deposits were identified in the field and correlated with specific eruptive events with the aid of M. Coombs, J. Vallance, and K. Bull. Repeated susceptibility measurements were made on the matrix of the PFs and other deposits. The PFs erupted between Jan. 13-Feb. 2 all were characterized by relatively high K (900-1400 x 10-5 SI). Some flows erupted during this eruptive sequence traveled almost to the coast of Augustine Island and buried a small pond. Oxidized pyroclastic deposits at the pond site had markedly lower K values of ca. 400-800 x 10-5 SI. Coeval water-mediated lahars and hyper-concentrated flows derived from the early PFs were also found to have low K. Measurements of K on pyroclastic avalanche debris overlying or mixed with snow were variable, but generally fell into an intermediate range between the fresh PF deposits and those deposits reflecting extensive interaction with water and/or steam. This study demonstrates that the systematic measurement of magnetic susceptibility can be a useful tool in understanding pyroclastic flows and the processes and deposits that result when PFs interact with snow and water on the slopes of active volcanoes.

  10. Magmatic inflation at a dormant stratovolcano: 1996-1998 activity at Mount Peulik volcano, Alaska, revealed by satellite radar interferometry

    USGS Publications Warehouse

    Lu, Zhiming; Wicks, C., Jr.; Dzurisin, D.; Power, J.A.; Moran, S.C.; Thatcher, W.

    2002-01-01

    A series of ERS radar interferograms that collectively span the time interval from July 1992 to August 2000 reveal that a presumed magma body located 6.6 ??? 0.5 km beneath the southwest flank of the Mount Peulik volcano inflated 0.051 ??? 0.005 km3 between October 1996 and September 1998. Peulik has been active only twice during historical time, in 1814 and 1852, and the volcano was otherwise quiescent during the 1990s. The inflation episode spanned at least several months because separate interferograms show that the associated ground deformation was progressive. The average inflation rate of the magma body was ???0.003 km3/month from October 1996 to September 1997, peaked at 0.005 km3/month from 26 June to 9 October 1997, and dropped to ???0.001 km3/month from October 1997 to September 1998. An intense earthquake swarm, including three ML 4.8 - 5.2 events, began on 8 May 1998 near Becharof Lake, ???30 km northwest of Peulik. More than 400 earthquakes with a cumulative moment of 7.15 ?? 1017 N m were recorded in the area through 19 October 1998. Although the inflation and earthquake swarm occured at about the same time, the static stress changes that we calculated in the epicentral area due to inflation beneath Peulik appear too small to provide a causal link. The 1996-1998 inflation episode at Peulik confirms that satellite radar interferometry can be used to detect magma accumulation beneath dormant volcanoes at least several months before other signs of unrest are apparent. This application represents a first step toward understanding the eruption cycle at Peulik and other stratovolcanoes with characteristically long repose periods.

  11. At-sea observations of marine birds and their habitats before and after the 2008 eruption of Kasatochi volcano, Alaska

    USGS Publications Warehouse

    Drew, G.S.; Dragoo, D.E.; Renner, M.; Piatt, J.F.

    2010-01-01

    Kasatochi volcano, an island volcano in the Aleutian chain, erupted on 7-8 August 2008. The resulting ash and pyroclastic flows blanketed the island, covering terrestrial habitats. We surveyed the marine environment surrounding Kasatochi Island in June and July of 2009 to document changes in abundance or distribution of nutrients, fish, and marine birds near the island when compared to patterns observed on earlier surveys conducted in 1996 and 2003. Analysis of SeaWiFS satellite imagery indicated that a large chlorophyll-a anomaly may have been the result of ash fertilization during the eruption. We found no evidence of continuing marine fertilization from terrestrial runoff 10 months after the eruption. At-sea surveys in June 2009 established that the most common species of seabirds at Kasatochi prior to the eruption, namely crested auklets (Aethia cristatella) and least auklets (Aethia pusilla) had returned to Kasatochi in relatively high numbers. Densities from more extensive surveys in July 2009 were compared with pre-eruption densities around Kasatochi and neighboring Ulak and Koniuji islands, but we found no evidence of an eruption effect. Crested and least auklet populations were not significantly reduced by the initial explosion and they returned to attempt breeding in 2009, even though nesting habitat had been rendered unusable. Maps of pre- and post-eruption seabird distribution anomalies indicated considerable variation, but we found no evidence that observed distributions were affected by the 2008 eruption. ?? 2010 Regents of the University of Colorado.

  12. Disruption of Drift glacier and origin of floods during the 1989-1990 eruptions of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Trabant, D.C.; Waitt, R.B.; Major, J.J.

    1994-01-01

    Melting of snow and glacier ice during the 1989-1990 eruption of Redoubt Volcano caused winter flooding of the Drift River. Drift glacier was beheaded when 113 to 121 ?? 106 m3 of perennial snow and ice were mechanically entrained in hot-rock avalanches and pyroclastic flows initiated by the four largest eruptions between 14 December 1989 and 14 March 1990. The disruption of Drift glacier was dominated by mechanical disaggregation and entrainment of snow and glacier ice. Hot-rock avalanches, debris flows, and pyroclastic flows incised deep canyons in the glacier ice thereby maintaining a large ice-surface area available for scour by subsequent flows. Downvalley flow rheologies were transformed by the melting of snow and ice entrained along the upper and middle reaches of the glacier and by seasonal snowpack incorporated from the surface of the lower glacier and from the river valley. The seasonal snowpack in the Drift River valley contributed to lahars and floods a cumulative volume equivalent to about 35 ?? 106 m3 of water, which amounts to nearly 30% of the cumulative flow volume 22 km downstream from the volcano. The absence of high-water marks in depressions and of ice-collapse features in the glacier indicated that no large quantities of meltwater that could potentially generate lahars were stored on or under the glacier; the water that generated the lahars that swept Drift River valley was produced from the proximal, eruption-induced volcaniclastic flows by melting of snow and ice. ?? 1994.

  13. A catastrophic flood caused by drainage of a caldera lake at Aniakchak Volcano, Alaska, and implications for volcanic hazards assessment

    USGS Publications Warehouse

    Waythomas, C.F.; Walder, J.S.; McGimsey, R.G.; Neal, C.A.

    1996-01-01

    Aniakchak caldera, located on the Alaska Peninsula of southwest Alaska, formerly contained a large lake (estimated volume 3.7 ?? 109 m3) that rapidly drained as a result of failure of the caldera rim sometime after ca. 3400 yr B.P. The peak discharge of the resulting flood was estimated using three methods: (1) flow-competence equations, (2) step-backwater modeling, and (3) a dam-break model. The results of the dam-break model indicate that the peak discharge at the breach in the caldera rim was at least 7.7 ?? 104 m3 s-1, and the maximum possible discharge was ???1.1 ?? 106 m3 s-1. Flow-competence estimates of discharge, based on the largest boulders transported by the flood, indicate that the peak discharge values, which were a few kilometers downstream of the breach, ranged from 6.4 ?? 105 to 4.8 ?? 106 m3 s-1. Similar but less variable results were obtained by step-backwater modeling. Finally, discharge estimates based on regression equations relating peak discharge to the volume and depth of the impounded water, although limited by constraining assumptions, provide results within the range of values determined by the other methods. The discovery and documentation of a flood, caused by the failure of the caldera rim at Aniakchak caldera, underscore the significance and associated hydrologic hazards of potential large floods at other lake-filled calderas.

  14. High-resolution satellite and airborne thermal infrared imaging of precursory unrest and 2009 eruption of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Wessels, Rick L.; Vaughan, R. Greg; Patrick, Matthew R.; Coombs, Michelle L.

    2013-01-01

    A combination of satellite and airborne high-resolution visible and thermal infrared (TIR) image data detected and measured changes at Redoubt Volcano during the 2008–2009 unrest and eruption. The TIR sensors detected persistent elevated temperatures at summit ice-melt holes as seismicity and gas emissions increased in late 2008 to March 2009. A phreatic explosion on 15 March was followed by more than 19 magmatic explosive events from 23 March to 4 April that produced high-altitude ash clouds and large lahars. Two (or three) lava domes extruded and were destroyed between 23 March and 4 April. After 4 April, the eruption extruded a large lava dome that continued to grow until at least early July 2009.

  15. Mount St. Helens and Kilauea volcanoes

    SciTech Connect

    Barrat, J. )

    1989-01-01

    Mount St. Helens' eruption has taught geologists invaluable lessons about how volcanoes work. Such information will be crucial in saving lives and property when other dormant volcanoes in the northwestern United States--and around the world--reawaken, as geologists predict they someday will. Since 1912, scientists at the U.S. Geological Survey's Hawaiian Volcano Observatory have pioneered the study of volcanoes through work on Mauna Loa and Kilauea volcanoes on the island of Hawaii. In Vancouver, Wash., scientists at the Survey's Cascades Volcano Observatory are studying the after-effects of Mount St. Helens' catalysmic eruption as well as monitoring a number of other now-dormant volcanoes in the western United States. This paper briefly reviews the similarities and differences between the Hawaiian and Washington volcanoes and what these volcanoes are teaching the volcanologists.

  16. Volcano seismology, hazards assessment

    NASA Astrophysics Data System (ADS)

    Mori, Jim

    1995-07-01

    The last few years have seen several impressive examples of seismic monitoring at volcanoes to provide warnings that have saved lives and property. Changes in the rates and character of volcanic earthquakes provided precursory signs to explosive eruptions of moderate size at Redoubt volcano (Alaska), Mount Unzen (Japan), Mount Spurr (Alaska), and Rabaul caldera (Papua New Guinea), as well as the large eruption at Mount Pinatubo (Philippines). In all these cases, information was successfully communicated and put to practical use through broadcasts of public warnings prior to the eruptions and evacuations were initiated for the volcanoes located in populated areas. At Mount Pinatubo, probably thousands and possibly tens of thousands of lives were saved.

  17. Temporal and spatial variation of local stress fields before and after the 1992 eruptions of Crater Peak vent, Mount Spurr volcano, Alaska

    USGS Publications Warehouse

    Roman, D.C.; Moran, S.C.; Power, J.A.; Cashman, K.V.

    2004-01-01

    We searched for changes in local stress-field orientation at Mount Spurr volcano, Alaska, between August 1991 and December 2001. This study focuses on the stress-field orientation beneath Crater Peak vent, the site of three eruptions in 1992, and beneath the summit of Mount Spurr. Local stress tensors were calculated by inverting subsets of 140 fault-plane solutions for earthquakes beneath Crater Peak and 96 fault-plane solutions for earthquakes beneath Mount Spurr. We also calculated an upper-crustal regional stress tensor by inverting fault-plane solutions for 66 intraplate earthquakes located near Mount Spurr during 1991-2001. Prior to the 1992 eruptions, and for 11 months beginning with a posteruption seismic swarm, the axis of maximum compressive stress beneath Crater Peak was subhorizontal and oriented N67-76??E, approximately perpendicular to the regional axis of maximum compressive stress (N43??W). The strong temporal correlation between this horizontal stress-field rotation (change in position of the ??1/ ??3 axes relative to regional stress) and magmatic activity indicates that the rotation was related to magmatic activity, and we suggest that the Crater Peak stress-field rotation resulted from pressurization of a network of dikes. During the entire study period, the stress field beneath the summit of Mount Spurr also differed from the regional stress tensor and was characterized by a vertical axis of maximum compressive stress. We suggest that slip beneath Mount Spurr's summit occurs primarily on a major normal fault in response to a combination of gravitational loading, hydrothermal circulation, and magmatic processes beneath Crater Peak. Online material: Regional and local fault-plane solutions.

  18. Thickness distribution of a cooling pyroclastic flow deposit on Augustine Volcano, Alaska: Optimization using InSAR, FEMs, and an adaptive mesh algorithm

    USGS Publications Warehouse

    Masterlark, Timothy; Lu, Zhiming; Rykhus, Russ

    2006-01-01

    Interferometric synthetic aperture radar (InSAR) imagery documents the consistent subsidence, during the interval 1992-1999, of a pyroclastic flow deposit (PFD) emplaced during the 1986 eruption of Augustine Volcano, Alaska. We construct finite element models (FEMs) that simulate thermoelastic contraction of the PFD to account for the observed subsidence. Three-dimensional problem domains of the FEMs include a thermoelastic PFD embedded in an elastic substrate. The thickness of the PFD is initially determined from the difference between post- and pre-eruption digital elevation models (DEMs). The initial excess temperature of the PFD at the time of deposition, 640 ??C, is estimated from FEM predictions and an InSAR image via standard least-squares inverse methods. Although the FEM predicts the major features of the observed transient deformation, systematic prediction errors (RMSE=2.2 cm) are most likely associated with errors in the a priori PFD thickness distribution estimated from the DEM differences. We combine an InSAR image, FEMs, and an adaptive mesh algorithm to iteratively optimize the geometry of the PFD with respect to a minimized misfit between the predicted thermoelastic deformation and observed deformation. Prediction errors from an FEM, which includes an optimized PFD geometry and the initial excess PFD temperature estimated from the least-squares analysis, are sub-millimeter (RMSE=0.3 mm). The average thickness (9.3 m), maximum thickness (126 m), and volume (2.1 ?? 107 m3) of the PFD, estimated using the adaptive mesh algorithm, are about twice as large as the respective estimations for the a priori PFD geometry. Sensitivity analyses suggest unrealistic PFD thickness distributions are required for initial excess PFD temperatures outside of the range 500-800 ??C. ?? 2005 Elsevier B.V. All rights reserved.

  19. Punctuated Evolution of Volcanology: An Observatory Perspective

    NASA Astrophysics Data System (ADS)

    Burton, W. C.; Eichelberger, J. C.

    2010-12-01

    Volcanology from the perspective of crisis prediction and response-the primary function of volcano observatories-is influenced both by steady technological advances and singular events that lead to rapid changes in methodology and procedure. The former can be extrapolated somewhat, while the latter are surprises or shocks. Predictable advances include the conversion from analog to digital systems and the exponential growth of computing capacity and data storage. Surprises include eruptions such as 1980 Mount St Helens, 1985 Nevado del Ruiz, 1989-1990 Redoubt, 1991 Pinatubo, and 2010 Eyjafjallajokull; the opening of GPS to civilian applications, and the advent of an open Russia. Mount St Helens switched the rationale for volcanology in the USGS from geothermal energy to volcano hazards, Ruiz and Pinatubo emphasized the need for international cooperation for effective early warning, Redoubt launched the effort to monitor even remote volcanoes for purposes of aviation safety, and Eyjafjallajokull hammered home the need for improved ash-dispersion and engine-tolerance models; better GPS led to a revolution in volcano geodesy, and the new Russian Federation sparked an Alaska-Kamchatka scientific exchange. The pattern has been that major funding increases for volcano hazards occur after these unpredictable events, which suddenly expose a gap in capabilities, rather than out of a calculated need to exploit technological advances or meet a future goal of risk mitigation. It is up to the observatory and national volcano hazard program to leverage these sudden funding increases into a long-term, sustainable business model that incorporates both the steadily increasing costs of staff and new technology and prepares for the next volcano crisis. Elements of the future will also include the immediate availability on the internet of all publically-funded volcano data, and subscribable, sophisticated hazard alert systems that run computational, fluid dynamic eruption models. These models will be coupled with risk assessments in which the parameters are adjusted to an emerging situation, while accessing global eruption databases in order to construct eruption event trees with statistically sound probabilities. Design of these alert systems will necessarily require the joint input of scientists and emergency management leaders. All of this can be visualized now, and programs such as VHub, WOVOdat, and NVEWS are working towards its eventual reality. Technological advances will make possible in a crisis the tapping of a global pool of expertise, which may have the effect of diminishing the importance of observatories as physical entities-however, familiarity with the nearby, monitored volcanoes and impacted populations will always require their presence. What is also clear about the future is that there must be more international communication and cooperation. We do this quite well scientifically, but not so well in terms of observatory operations or best practices. While parallel paths can be stimulating through diversity and competition, there is no need for every national program to separately invent the wheel. Changes will also need to be made in institutional expectations of scientists, which currently overemphasize solitary achievement at the expense of community efforts.

  20. Geochemistry, isotopic composition and origin of fluids emanating from mud volcanoes in the Copper River Basin, Alaska. Final report

    SciTech Connect

    Motyka, R.J.; Hawkins, D.B.; Poreda, R.J.; Jeffries, A.

    1986-05-01

    Two compositionally different groups of mud volcanoes exist in the Copper River Basin: the Tolsona group which discharges Na-Ca rich, HCO/sub 3/-SO/sub 4/ poor saline waters accompanied by small amounts of gas, composed predominately of CH/sub 4/ and N/sub 2/; and the Klawasi group which discharges Ca poor, Na-HCO/sub 3/ rich saline waters accompanied by enormous amounts of CO/sub 2/. The Tolsona-type water chemistry and isotopic composition could have been produced through the following processes: dilution of original interstitial seawaters with paleo-meteoric waters, possibly during a period of uplift in the mid-Cretaceous; loss of HCO/sub 3/ and SO/sub 4/ and modification of other constituent concentrations by shale-membrane filtration; further depletion of Mg, K, HCO/sub 3/, and SO/sub 4/, and enrichment in Ca and Sr through dolomitization, hydrolysis, and clay-forming processes; and leaching of B, I, Li, and SiO/sub 2/ from marine sediments. Compared to the Tolsona waters, the Klawasi waters are strongly enriched in Li, Na, K, Mg, HCO/sub 3/, SO/sub 4/, B, SiO/sub 2/ and delta/sup 18/O and strongly depleted in Ca, Sr and D. The Klawasi wates also contain high concentrations of arsenic (10 to 48 ppM). The differences in fluid chemistry between Klawasi and Tolsona can be explained as the result of the interaction of fluids derived from a magmatic intrusion and contact decarbonation of limestone beds underlying the Klawasi area with overlying Tolsona-type formation waters.

  1. Characterization of pyroclastic deposits and pre-eruptive soils following the 2008 eruption of Kasatochi Island Volcano, Alaska

    USGS Publications Warehouse

    Wang, B.; Michaelson, G.; Ping, C.-L.; Plumlee, G.; Hageman, P.

    2010-01-01

    The 78 August 2008 eruption of Kasatochi Island volcano blanketed the island in newly generated pyroclastic deposits and deposited ash into the ocean and onto nearby islands. Concentrations of water soluble Fe, Cu, and Zn determined from a 1:20 deionized water leachate of the ash were sufficient to provide short-term fertilization of the surface ocean. The 2008 pyroclastic deposits were thicker in concavities at bases of steeper slopes and thinner on steep slopes and ridge crests. By summer 2009, secondary erosion had exposed the pre-eruption soils along gulley walls and in gully bottoms on the southern and eastern slopes, respectively. Topographic and microtopographic position altered the depositional patterns of the pyroclastic flows and resulted in pre-eruption soils being buried by as little as 1 m of ash. The different erosion patterns gave rise to three surfaces on which future ecosystems will likely develop: largely pre-eruptive soils; fresh pyroclastic deposits influenced by shallowly buried, pre-eruptive soil; and thick (>1 m) pyroclastic deposits. As expected, the chemical composition differed between the pyroclastic deposits and the pre-eruptive soils. Pre-eruptive soils hold stocks of C and N important for establishing biota that are lacking in the fresh pyroclastic deposits. The pyroclastic deposits are a source for P and K but have negligible nutrient holding capacity, making these elements vulnerable to leaching loss. Consequently, the pre-eruption soils may also represent an important long-term P and K source. ?? 2010 Regents of the University of Colorado.

  2. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2009

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Searcy, Cheryl K.

    2010-01-01

    Between January 1 and December 31, 2009, the Alaska Volcano Observatory (AVO) located 8,829 earthquakes, of which 7,438 occurred within 20 kilometers of the 33 volcanoes with seismograph subnetworks. Monitoring highlights in 2009 include the eruption of Redoubt Volcano, as well as unrest at Okmok Caldera, Shishaldin Volcano, and Mount Veniaminof. Additionally severe seismograph subnetwork outages resulted in four volcanoes (Aniakchak, Fourpeaked, Korovin, and Veniaminof) being removed from the formal list of monitored volcanoes in late 2009. This catalog includes descriptions of: (1) locations of seismic instrumentation deployed during 2009; (2) earthquake detection, recording, analysis, and data archival systems; (3) seismic velocity models used for earthquake locations; (4) a summary of earthquakes located in 2009; and (5) an accompanying UNIX tar-file with a summary of earthquake origin times, hypocenters, magnitudes, phase arrival times, location quality statistics, daily station usage statistics, all files used to determine the earthquake locations in 2009, and a dataless SEED volume for the AVO seismograph network.

  3. Timing, Distribution, and Character of Tephra Fall from the 2005-2006 Eruption of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Wallace, K. L.; Neal, C.; McGimsey, G.

    2006-12-01

    The 2005-2006 eruption of Augustine Volcano produced tephra-fall deposits during four eruptive phases. The island setting, deposition of thin, fine-grained fall deposits onto the snowpack, and subsequent reworking by high winds and surface-water flow has removed much of the original proximal fall record. During the late precursory phase (December 2005), small phreatic explosions produced very light, localized tephra fall. Tephra from one such event is composed of altered and fresh, possibly juvenile, glass shards. The greatest volume of tephra fall was produced during the explosive phase (January 11 - 28) when 13 discrete explosive events generated plumes between 3 -14 km ASL during a period of dome building and collapse. Associated strong seismicity lasted 1-11 min (avg 4 min), closely matching the duration of plume generation followed by detachment from the vent and distribution by local winds. On January 11, explosions generated two plumes to ~9 km ASL and deposited trace amounts of ash on communities surrounding Lake Iliamna W and NW of Augustine. Tephra from this event are not well preserved and were likely small in volume, but proximal and distal samples collected during the eruption are composed mainly of older dense dome fragments and crystals with little to no juvenile material. On January 13 and 14, six discrete explosions produced plumes to 9 - 11 km ASL that dispersed to the N-NE and deposited < 1mm of ash on Homer, Seldovia, Nanwelek and Port Graham. Coarse proximal fall deposits are composed mainly of olive- green, scoriaceous, low-silica andesite; subordinate black, dense, porphyritic low-silica andesite; white, variably vesicular high-silica andesite; and accidental lithic fragments. During this time, low-silica andesite dome extrusion was occurring. An explosion on January 17 produced a plume to ~14 km ASL that dispersed to the W-NW and deposited 1 mm of ash on communities surrounding Lake Iliamna. Coarse proximal fall deposits contain the same clast types as the January 13-14 events, with proportionally more white high-silica andesite that ranges to higher vesicularities and only rare accidental lithic clasts. On January 27-28, four explosions produced plumes to 3-9 km ASL, that dispersed to the SE and S-SW leading into the continuous phase (January 28 - February 2), characterized by constant low-level ash emissions punctuated by discrete explosions of tephra to 3-8 km ASL. The plume was dispersed to the S depositing ~1mm of ash on Afognak and Kodiak Islands (January 27-February 2). No correlative proximal coarse-grained fall deposits have been identified. Fine to very fine light gray, massive ash deposits are perhaps the most common fall fraction on the island and likely represent elutriation from pyroclastic flows generated during this time interval (from high-silica andesite dome collapse). The effusive phase (February 2-late March) produced a low-silica andesite lava dome and flows. Very fine, pinkish massive ash deposits on the N, W and E sectors overlie other fall deposits and are likely elutriate from small block and ash flows associated with growth of steep-sided lava flows. No significant tephra plumes occurred during this time, although a small volume tephra deposit of mostly black, dense, low-silica andesite overlies pyroclastic-flow deposits from mid January and likely represents a small explosion which is corroborated by infrasound sensor data during this phase.

  4. Earthquake triggering at alaskan volcanoes following the 3 November 2002 denali fault earthquake

    USGS Publications Warehouse

    Moran, S.C.; Power, J.A.; Stihler, S.D.; Sanchez, J.J.; Caplan-Auerbach, J.

    2004-01-01

    The 3 November 2002 Mw 7.9 Denali fault earthquake provided an excellent opportunity to investigate triggered earthquakes at Alaskan volcanoes. The Alaska Volcano Observatory operates short-period seismic networks on 24 historically active volcanoes in Alaska, 247-2159 km distant from the mainshock epicenter. We searched for evidence of triggered seismicity by examining the unfiltered waveforms for all stations in each volcano network for ???1 hr after the Mw 7.9 arrival time at each network and for significant increases in located earthquakes in the hours after the mainshock. We found compelling evidence for triggering only at the Katmai volcanic cluster (KVC, 720-755 km southwest of the epicenter), where small earthquakes with distinct P and 5 arrivals appeared within the mainshock coda at one station and a small increase in located earthquakes occurred for several hours after the mainshock. Peak dynamic stresses of ???0.1 MPa at Augustine Volcano (560 km southwest of the epicenter) are significantly lower than those recorded in Yellowstone and Utah (>3000 km southeast of the epicenter), suggesting that strong directivity effects were at least partly responsible for the lack of triggering at Alaskan volcanoes. We describe other incidents of earthquake-induced triggering in the KVC, and outline a qualitative magnitude/distance-dependent triggering threshold. We argue that triggering results from the perturbation of magmatic-hydrothermal systems in the KVC and suggest that the comparative lack of triggering at other Alaskan volcanoes could be a result of differences in the nature of magmatic-hydrothermal systems.

  5. Petrology and geochemistry of ca. 2100-1000 a.B.P. magmas of Augustine volcano, Alaska, based on analysis of prehistoric pumiceous tephra

    NASA Astrophysics Data System (ADS)

    Tappen, Christine M.; Webster, James D.; Mandeville, Charles W.; Roderick, David

    2009-05-01

    Geochemical and textural features of whole-rock samples, phenocrysts, matrix glasses, and silicate melt inclusions from five prehistoric pumiceous tephra units of Augustine volcano, Alaska, were investigated to interpret processes of magma storage and evolution. The bulk-rock compositions of the tephra (designated G, erupted ca. 2100 a.B.P.; I ca. 1700 a.B.P.; H ca. 1400 a.B.P.; and C1 and C2 ca. 1000 a.B.P.) are silicic andesite; they contain rhyolitic matrix glasses and silicate melt inclusions with 74-79 wt.% SiO 2. The rocks are comprised of microlite-bearing matrix glass and phenocrysts of plagioclase, orthopyroxene, clinopyroxene, magnesio-hornblende, titanomagnetite, and ilmenite ± Al-rich amphibole with minor to trace apatite and rare sulfides and quartz. The felsic melt inclusions in plagioclase, pyroxenes, and amphibole are variably enriched in volatile components and contain 1.6-8.0 wt.% H 2O, 2100-5400 ppm Cl, < 40-1330 ppm CO 2, and 30-390 ppm S. Constraints from Fe-Ti oxides imply that magma evolution occurred at 796 ± 6 °C to 896 ± 8 °C and log ƒ O2 of NNO + 2.2 to + 2.6. This is consistent with conditions recorded for 1976, 1986, and 2006 eruptive materials and implies that magmatic and eruptive processes have varied little during the past 2100 years. Prehistoric Augustine magmas represented by these silicic andesites evolved via fractional crystallization, magma mingling and mixing, and/or chemical contamination due to magma-volcanic rock interaction. The occurrence of fractional crystallization is supported by the abundance of normally zoned phenocrysts, the presence of felsic matrix glass and melt inclusions within andesitic rock samples, trace-element data, and by geochemical modeling. The modeling constrains the influence of crystal fractionation on melt differentiation and is consistent with the evolution of the melt phase from felsic andesite to rhyodacite compositions. Magma mixing, mingling, and/or contamination by magma-volcanic rock interaction are indicated by abundant reversely zoned phenocrysts, rare mixed pumice-bearing rock samples, and abundant resorption-growth features in plagioclase.

  6. Experimental Calibration of Amphibole Break Down Rates in Response to Decompression and Heating: Examples From the 1989-1990 eruptions of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Browne, B. L.; Gardner, J. E.

    2002-12-01

    Amphiboles are an important mineral common to a variety of magmas, and are especially sensitive to subtle variations in the water content and temperature of the surrounding melt that induces disequilibria through changing pressure (via ascent) or heating (via magma mixing events). For example, as magma rises toward the surface, hydrous amphiboles, stable at high water pressures, react with their surrounding degassing melt to form anhydrous minerals. Also, when magmas of intermediate composition mix with more primitive magmas of higher temperature, hydrous amphiboles, stable at lower temperatures break down by reacting with the resulting hybrid melt. Only a handful of studies have been performed that directly address the stability of amphiboles as an indicator of the rate at which magmatic processes such as mixing and ascent occur. We examine the stability of amphibole through a series of decompression and heating experiments using dacitic and andesitic magma erupted from Redoubt volcano, Alaska in 1989-1990. Redoubt dacite contains magnesio-hornblende and orthopyroxene, whereas the andesite contains pargasitic amphiboles and clinopyroxene. Both contain plagioclase, magnetite, and ilmenite in rhyolitic glass. The stability limits of the hornblende and pargasite were first constrained by phase-equilibrium experiments. For the dacite, experiments indicate that the magma last equilibrated at approximately 840° C and 155 MPa. Isothermal decompression experiments were thus carried to examine the growth rate of reaction rims on the hornblendes in response to the degassing melt. All decompression experiments were initially held at 840° C and 150 MPa for approximately 5 days before decompression. These experiments show that during a 840° C constant rate decompression from 6 km to the surface, no reaction rims developed on amphibole in 2 or 3.5 days (10-20 cm/s), a 2-um rim developed in 5.5 days (1 cm/s), and a 9-um rim developed in 20 days (0.5 cm/s). The third series of experiments performed in this study were isobaric thermal breakdown experiments to calibrate amphibole breakdown rates induced by heating. These experimental data are different compared to other comparable studies (i.e. 1980 Mount St. Helens dacite, 1995-97 Soufriere Hills andesite), despite the overall similarity in amphibole chemistry. This suggests that breakdown reactions in amphiboles relate predominantly to melt composition and viscosity (water content, temperature, and water pressure), rather than to chemical variability of mineral phases.

  7. A numerical investigation of choked flow dynamics and its application to the triggering mechanism of long-period events at Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Morrissey, M.M.; Chouet, B.A.

    1997-01-01

    We use numerical simulations of transonic flow through a crack to study the dynamics of the formation of shock waves downstream from a nozzle-like constriction inside the crack. The model solves the full set of Navier-Stokes equations in two dimensions via an explicit multifield finite difference representation. The crack walls are assumed to be perfectly rigid, and elastic coupling to the solid is not considered. The simulations demonstrate how the behavior of unsteady shock waves near the walls can produce recurring step-like pressure transients in the flow, which in turn induce resonance of the fluid-filled crack. The motion of the shock waves is governed primarily by smooth, low-amplitude pressure fluctuations at the outlet of the crack. The force induced on the walls scales with the amplitude of the shock, which is a function of the magnitude of the inlet pressure, aperture of the constriction, and thickness of the boundary layer. The applied force also scales in proportion to the spatial extent of the shock excursion, which depends on the fluctuation rate of outlet pressure. Using the source parameters of long-period (LP) events at Redoubt Volcano, Alaska, as a guide for our simulations, we infer that coupling of the shock to the walls occurs for crack inlet to outlet pressure ratios pipo > 2.31 and that the position of the shock front becomes most sensitive to outlet pressure fluctuations for flow regimes with pipo > 2.48. For such regimes, fluctuations of outlet pressure of up to ??0.5 MPa at rates up to 3 MPa/s are sufficient to induce pressure transients with magnitudes up to 12.5 MPa over 0.1-2.5 m of the walls within ???0.5 s. These flow parameters may be adequate for triggering the LP events in the precursory swarm to the December 14, 1989, eruption of Redoubt. According to the flow model the recurrence rate and amplitudes of LP events are inferred to be a manifestation of the response of a shallow hydrothermal reservoir to the sustained injection of superheated steam from a magma column roofing below this reservoir.

  8. Long-period seismicity at Shishaldin volcano (Alaska) in 2003-2004: Indications of an upward migration of the source before a minor eruption

    NASA Astrophysics Data System (ADS)

    Cusano, P.; Palo, M.; West, M. E.

    2015-01-01

    We have analyzed the long-period (LP) seismic activity at Shishaldin volcano (Aleutians Islands, Alaska) in the period October 2003-July 2004, during which a minor eruption took place in May 2004, with ash and steam emissions, thermal anomalies, volcanic tremor and small explosions. We have focused the attention on the time evolution of LP rate, size, spectra and polarization dip angle along the dataset. We find an evolution toward more shallow dip angles in the polarization of the waveforms during the sequence. The dip angle is a manifestation of the source location. Because the LP seismic sources are presumed to reflect the aggregation of gas slug or pockets within the melt, we use the polarization dip at the LP onset as a proxy for the nucleation depth of the seismic events within the conduit. We refer to this parameter as the nucleation dip and the position along the conduit of the gas aggregation as nucleation depth. The nucleation dip changes throughout the dataset. It shows a sharp decrease between the end of December 2003 and the end of January 2004, followed by a gradual increase until the onset of the eruption. At the same time, a general increase of the LP rate occurs. We have associated the dip evolution with a sinking and a subsequent decrease of the nucleation depth, which would quickly migrate up to about 8 km below the crater rim, followed by a slow depth decrease which culminates in the eruption. The change in the nucleation depth reflects either a pressure variation within the plumbing system, which would affect the confining pressure experienced by the gas aggregations. We have imputed such a pressure change to the intrusion of batches of magma from a deeper magma chamber (< 10 km) toward a shallower one (> 5 km). For a cylindric conduit with rigid walls, this leads to a volume of the injected new magma of 105-107 m3, compatible with estimates in other areas, suggesting that the LP process can be considered a good proxy of the thermodynamical conditions of the shallow plumbing system.

  9. A numerical investigation of choked flow dynamics and its application to the triggering mechanism of long-period events at Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Morrissey, Meghan M.; Chouet, Bernard A.

    1997-04-01

    We use numerical simulations of transonic flow through a crack to study the dynamics of the formation of shock waves downstream from a nozzle-like constriction inside the crack. The model solves the full set of Navier-Stokes equations in two dimensions via an explicit multifield finite difference representation. The crack walls are assumed to be perfectly rigid, and elastic coupling to the solid is not considered. The simulations demonstrate how the behavior of unsteady shock waves near the walls can produce recurring step-like pressure transients in the flow, which in turn induce resonance of the fluid-filled crack. The motion of the shock waves is governed primarily by smooth, low-amplitude pressure fluctuations at the outlet of the crack. The force induced on the walls scales with the amplitude of the shock, which is a function of the magnitude of the inlet pressure, aperture of the constriction, and thickness of the boundary layer. The applied force also scales in proportion to the spatial extent of the shock excursion, which depends on the fluctuation rate of outlet pressure. Using the source parameters of long-period (LP) events at Redoubt Volcano, Alaska, as a guide for our simulations, we infer that coupling of the shock to the walls occurs for crack inlet to outlet pressure ratios pi/po>2.31 and that the position of the shock front becomes most sensitive to outlet pressure fluctuations for flow regimes with pi/po>2.48. For such regimes, fluctuations of outlet pressure of up to ±0.5 MPa at rates up to 3 MPa/s are sufficient to induce pressure transients with magnitudes up to 12.5 MPa over 0.1-2.5 m of the walls within ˜0.5 s. These flow parameters may be adequate for triggering the LP events in the precursory swarm to the December 14, 1989, eruption of Redoubt. According to the flow model the recurrence rate and amplitudes of L.P events are inferred to be a manifestation of the response of a shallow hydrothermal reservoir to the sustained injection of superheated steam from a magma column roofing below this reservoir.

  10. An experiment to detect and locate lightning associated with eruptions of Redoubt Volcano

    USGS Publications Warehouse

    Hoblitt, R.P.

    1994-01-01

    A commercially-available lightning-detection system was temporarily deployed near Cook Inlet, Alaska in an attempt to remotely monitor volcanogenic lightning associated with eruptions of Redoubt Volcano. The system became operational on February 14, 1990; lightning was detected in 11 and located in 9 of the 13 subsequent eruptions. The lightning was generated by ash clouds rising from pyroclastic density currents produced by collapse of a lava dome emplaced near Redoubt's summit. Lightning discharge (flash) location was controlled by topography, which channeled the density currents, and by wind direction. In individual eruptions, early flashes tended to have a negative polarity (negative charge is lowered to ground) while late flashes tended to have a positive polarity (positive charge is lowered to ground), perhaps because the charge-separation process caused coarse, rapid-settling particles to be negatively charged and fine, slow-settling particles to be positively charged. Results indicate that lightning detection and location is a useful adjunct to seismic volcano monitoring, particularly when poor weather or darkness prevents visual observation. The simultaneity of seismicity and lightning near a volcano provides the virtual certainty that an ash cloud is present. This information is crucial for aircraft safety and to warn threatened communities of impending tephra falls. The Alaska Volcano Observatory has now deployed a permanent lightning-detection network around Cook Inlet. ?? 1994.

  11. Evidence for Deep Tectonic Tremor in the Alaska-Aleutian Subduction Zone

    NASA Astrophysics Data System (ADS)

    Brown, J. R.; Prejean, S. G.; Beroza, G. C.; Gomberg, J. S.; Haeussler, P. J.

    2010-12-01

    We search for, characterize, and locate tremor not associated with volcanoes along the Alaska-Aleutian subduction zone using continuous seismic data recorded by the Alaska Volcano Observatory and Alaska Earthquake Information Center from 2005 to the present. Visual inspection of waveform spectra and time series reveal dozens of 10 to 20-minute bursts of tremor throughout the Alaska-Aleutian subduction zone (Peterson, 2009). Using autocorrelation methods, we show that these tremor signals are composed of hundreds of repeating low-frequency earthquakes (LFEs) as has been found in other circum-Pacific subduction zones. We infer deep sources based on phase arrival move-out times of less than 4 seconds across multiple monitoring networks (max. inter-station distances of 50 km), which are designed to monitor individual volcanoes. We find tremor activity is localized in 7 segments: Cook Inlet, Shelikof Strait, Alaska Peninsula, King Cove, Unalaska-Dutch Harbor, Andreanof Islands, and the Rat Islands. Locations along the Cook Inlet, Shelikof Straight and Alaska Peninsula are well constrained due to adequate station coverage. LFE hypocenters in these regions are located on the plate interface and form a sharp edge near the down-dip limit of the 1964 M 9.2 rupture area. Although the geometry, age, thermal structure, frictional and other relevant properties of the Alaska-Aleutian subduction are poorly known, it is likely these characteristics differ along its entire length, and also differ from other subduction zones where tremor has been found. LFE hypocenters in the remaining areas are also located down-dip of the most recent M 8+ megathrust earthquakes, between 60-75 km depth and almost directly under the volcanic arc. Although these locations are less well constrained, our preliminary results suggest LFE/tremor activity marks the down-dip rupture limit for megathrust earthquakes in this subduction zone. Also, we cannot rule out the possibility that our observations could be related deep magmatic processes.

  12. Remotely Triggered Seismicity at Alaskan Volcanoes Following the Mw 7.9 Denali Fault Earthquake

    NASA Astrophysics Data System (ADS)

    Moran, S. C.; Sanchez, J. J.; Power, J. A.; Stihler, S. D.; McNutt, S. R.

    2002-12-01

    The November 3, 2002, Mw 7.9 Denali Fault earthquake provided the largest source yet to investigate triggered earthquakes at Alaskan volcanoes. The Alaska Volcano Observatory (AVO) operates short-period seismic networks on 24 historically active volcanoes in Alaska, 280 - 2100 km distant from the mainshock epicenter. The magnitude detection thresholds for these networks range from M 0.1 to M 1.5. Previous instances of triggered seismicity in Alaska have been recorded in the Katmai Volcanic Cluster, where a number of triggered events occurred following two large earthquakes on December 6, 1999 (60 km distant, Mw 7.0), and January 10, 2001 (35 km distant, Mw 6.8). We searched for evidence of triggered seismicity by examining the unfiltered waveforms for all stations in each volcano network for ~1 hour following the Mw 7.9 arrival. We looked for events within the mainshock coda with discrete P and S arrivals and/or arrivals on multiple stations. We also looked at filtered waveforms for time periods of several hours before and after the mainshock. We only found compelling evidence for triggering at the Katmai Volcanic Cluster (720-755 km SW of the mainshock), where two small earthquakes with distinct P and S arrivals appeared in the mainshock coda at one station. There was also a small increase in located earthquakes at Katmai over a period of several hours following the mainshock. Although it is certainly possible that triggered earthquakes occurred at other volcanoes while networks were clipped, our analysis indicates that any triggering was minimal. This is in striking contrast to triggered seismicity recorded at Yellowstone, Mammoth Mountain, The Geysers, Coso and possibly Mount Rainier following the Denali earthquake. The comparative lack of triggering could be a result of differences in size and/or activity of geothermal systems, directivity of the mainshock, the dominant frequency at each system, and/or local site conditions.

  13. Integrating SAR with Optical and Thermal Remote Sensing for Operational Near Real-Time Volcano Monitoring

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; Webley, P.; Dehn, J.; Arko, S. A.; McAlpin, D. B.

    2013-12-01

    Volcanic eruptions are among the most significant hazards to human society, capable of triggering natural disasters on regional to global scales. In the last decade, remote sensing techniques have become established in operational forecasting, monitoring, and managing of volcanic hazards. Monitoring organizations, like the Alaska Volcano Observatory (AVO), are nowadays heavily relying on remote sensing data from a variety of optical and thermal sensors to provide time-critical hazard information. Despite the high utilization of these remote sensing data to detect and monitor volcanic eruptions, the presence of clouds and a dependence on solar illumination often limit their impact on decision making processes. Synthetic Aperture Radar (SAR) systems are widely believed to be superior to optical sensors in operational monitoring situations, due to the weather and illumination independence of their observations and the sensitivity of SAR to surface changes and deformation. Despite these benefits, the contributions of SAR to operational volcano monitoring have been limited in the past due to (1) high SAR data costs, (2) traditionally long data processing times, and (3) the low temporal sampling frequencies inherent to most SAR systems. In this study, we present improved data access, data processing, and data integration techniques that mitigate some of the above mentioned limitations and allow, for the first time, a meaningful integration of SAR into operational volcano monitoring systems. We will introduce a new database interface that was developed in cooperation with the Alaska Satellite Facility (ASF) and allows for rapid and seamless data access to all of ASF's SAR data holdings. We will also present processing techniques that improve the temporal frequency with which hazard-related products can be produced. These techniques take advantage of modern signal processing technology as well as new radiometric normalization schemes, both enabling the combination of multiple observation geometries in change detection procedures. Additionally, it will be shown how SAR-based hazard information can be integrated with data from optical satellites, thermal sensors, webcams and models to create near-real time volcano hazard information. We will introduce a prototype monitoring system that integrates SAR-based hazard information into the near real-time volcano hazard monitoring system of the Alaska Volcano Observatory. This prototype system was applied to historic eruptions of the volcanoes Okmok and Augustine, both located in the North Pacific. We will show that for these historic eruptions, the addition of SAR data lead to a significant improvement in activity detection and eruption monitoring, and improved the accuracy and timeliness of eruption alerts.

  14. Hawaiian Volcanoes: Deep Underwater Perspectives

    NASA Astrophysics Data System (ADS)

    Takahashi, Eiichi; Lipman, Peter W.; Garcia, Michael O.; Naka, Jiro; Aramaki, Shigeo

    In the summer of 1963, when a group of Japanese scientists arrived at the aged building of the Hawaiian Volcano Observatory, run by the U.S. Geological Survey, there began a program of cooperation and friendship between American and Japanese volcanologists that continues to the present. The late Professor Takeshi Minakami, a top volcano-physicist long involved in research at various volcanoes, including Asama, then the most active volcano in Japan, led the Japanese group. The time coincided with a changeover in Hawaii, from the pioneering volcanologic studies of Harold Stearns, Gordon Macdonald, and Jerry Eaton to more comprehensive research by younger volcanologists. The Japanese team was also fortunate enough to witness a rift zone eruption at Kilauea volcano (Alae eruption, July 1963), a direct, eye-opening encounter with a volcano plumbing system in action.

  15. GlobVolcano: Global Monitoring of Volcanoes from Space

    NASA Astrophysics Data System (ADS)

    Tampellini, M. L.; Ratti, R.; Seifert, F. M.; Borgstrom, S.; Peltier, A.; Kaminski, E.; Bianchi, M.; Bronson, W.; Ferrucci, F.; Hirn, B.; Van der Voet, P.; van Geffen, J.

    2010-12-01

    The GlobVolcano project (2007-2010) is part of the Data User Element (DUE) programme of the European Space Agency (ESA). The objective of the project is to demonstrate EO-based (Earth Observation) services able to support the Volcano Observatories and other mandate users (Civil Protection, volcano scientific community) in their monitoring activities. The set of offered EO based information products is the following: - Deformation Mapping - Surface Thermal Anomalies - Volcanic Gas Emission - Volcanic Ash Tracking The information services are assessed in close cooperation with the user organizations for different types of volcano, from various geographical areas in various climatic zones. Users are directly and actively involved in the validation of the Earth Observation products, by comparing them with ground data available at each site. In a first phase, the GlobVolcano Information System was designed, implemented and validated, involving a limited number of test areas and respective user organizations (Colima in Mexico, Merapi in Indonesia, Soufrière Hills in Montserrat Island, Piton de la Fournaise in La Reunion Island, Karthala in Comore Islands, Stromboli and Volcano in Italy). In particular Deformation Mapping and Surface Thermal Anomalies results obtained for Piton de la Fournaise were compared with ground data measured by the volcano observatory. IPGP (Institut de Physique du Globe de Paris) is responsible for the validation activities. The second phase of the project (currently on-going) concerns the service provision on pre-operational basis. Fifteen volcanic sites located in four continents are monitored and as many user organizations are involved and cooperating with the project team. The GlobVolcano Information System includes two main elements: - The GlobVolcano Data Processing System, which consists of EO data processing subsystems located at each respective service centre. - The GlobVolcano Information Service, which is the provision infrastructure, including three elements: GlobVolcano Products Archives, GlobVolcano Metadata Catalogue, GlobVolcano User Interface (GVUI). The GlobVolcano Information System represents a significant step ahead towards the implementation of an operational, global observatory of volcanoes by a synergetic use of data from currently available Earth Observation satellites.

  16. Reunion Island Volcano Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On January 16, 2002, lava that had begun flowing on January 5 from the Piton de la Fournaise volcano on the French island of Reunion abruptly decreased, marking the end of the volcano's most recent eruption. These false color MODIS images of Reunion, located off the southeastern coast of Madagascar in the Indian Ocean, were captured on the last day of the eruption (top) and two days later (bottom). The volcano itself is located on the southeast side of the island and is dark brown compared to the surrounding green vegetation. Beneath clouds (light blue) and smoke, MODIS detected the hot lava pouring down the volcano's flanks into the Indian Ocean. The heat, detected by MODIS at 2.1 um, has been colored red in the January 16 image, and is absent from the lower image, taken two days later on January 18, suggesting the lava had cooled considerably even in that short time. Earthquake activity on the northeast flank continued even after the eruption had stopped, but by January 21 had dropped to a sufficiently low enough level that the 24-hour surveillance by the local observatory was suspended. Reunion is essentially all volcano, with the northwest portion of the island built on the remains of an extinct volcano, and the southeast half built on the basaltic shield of 8,630-foot Piton de la Fournaise. A basaltic shield volcano is one with a broad, gentle slope built by the eruption of fluid basalt lava. Basalt lava flows easily across the ground remaining hot and fluid for long distances, and so they often result in enormous, low-angle cones. The Piton de la Fournaise is one of Earth's most active volcanoes, erupting over 150 times in the last few hundred years, and it has been the subject of NASA research because of its likeness to the volcanoes of Mars. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  17. Geologic map of Mount Gareloi, Gareloi Island, Alaska

    USGS Publications Warehouse

    Coombs, Michelle L.; McGimsey, Robert G.; Browne, Brandon L.

    2012-01-01

    As part of an effort to both monitor and study all historically active volcanoes in Alaska, the Alaska Volcano Observatory (AVO) undertook a field program at Mount Gareloi in the summer of 2003. During a month-long period, seismic networks were installed at Mount Gareloi and the neighboring Tanaga volcanic cluster. During this time, we undertook the first geologic field study of the volcano since Robert Coats visited Gareloi Island for four days in 1946. Understanding the geology of this relatively small island is important from a hazards perspective, because Mount Gareloi lies beneath a heavily trafficked air route between North America and Asia and has frequently erupted airborne ash since 1760. At least two landslides from the island have deposited debris on the sea floor; thus, landslide-generated tsunamis are also a potential hazard. Since seismic instruments were installed in 2003, they have detected small but consistent seismic signals from beneath Mount Gareloi's edifice, suggesting an active hydrothermal system. Mount Gareloi is also important from the standpoint of understanding subduction-related volcanism, because it lies in the western portion of the volcanically active arc, where subduction is oblique to the arc front. Understanding the compositional evolution of Mount Gareloi fills a spatial gap in along-arc studies.

  18. Simultaneous Earthquake Swarms and Eruptions in Alaska, Fall 1996

    NASA Astrophysics Data System (ADS)

    McNutt, S. R.; Marzocchi, W.; Power, J. A.

    2001-12-01

    In 1996 the Alaska Volcano Observatory recorded an unprecedented level of seismic and volcanic activity. Pavlof Volcano erupted from Sept. 11 to Dec. 29; the strongest earthquake swarm to date occurred at Iliamna Volcano, peaking Aug. 15; a strong swarm began Sept. 25 at Strandline Lake, NE of Mount Spurr (Strandline may not be related to volcanism), peaking Oct. 7-28; and a vigorous swarm occurred beneath Martin and Mageik Volcanoes from Oct. 16-21, 1996. These volcanoes are located in an 870 km long section of the Alaska-Aleutian arc. No additional swarms or eruptions occurred at these volcanoes in the 5 years since 1996. We conducted two formal statistical tests to determine the likliehood of these events occurring randomly in the same time interval. The first test considered only the volcanoes at which swarms or eruptions occurred (7 of 13). We produced 10,000 synthetic catalogs under the assumption that the sites are independent. Time intervals of 30 to 360 days were tested. The monitoring began at different times, and the interval chosen for analysis ended on December 31, 2000. The second method is a hierarchical Bayesian model in which the probability of a swarm at each volcano is different but the parent population is the same. We evaluated all 13 volcanoes that were monitored in 1996. In both cases we found that the likliehood of the swarms and eruption occurring together by chance alone is small: less than 1 percent for the first test and about 1 percent for the second. Therefore we conclude that the events may have been triggered. We speculate that an arc-wide deformation pulse occurred, and also note that a M=8 earthquake took place in the central portion of the arc in May, 1996. The two may be related. No arc-wide continuous deformation data exist for 1996, so we cannot determine physical mechanisms. However, the high level of earthquake and volcanic activity in the Aleutian arc suggests that such triggering or interaction may occur again. It would be prudent to install continuous deformation instruments at several places in the arc in order to better understand such simultaneous seismic and volcanic activity.

  19. Redoubt Volcano: 2009 Eruption Overview

    NASA Astrophysics Data System (ADS)

    Bull, K. F.

    2009-12-01

    Redoubt Volcano is a 3110-m glaciated stratovolcano located 170 km SW of Anchorage, Alaska, on the W side of Cook Inlet. The edifice comprises a <1500-m-thick sequence of mid-Pleistocene to recent, basaltic to dacitic pyroclastic-, block-and-ash- and lava-flow deposits built on Jurassic tonalite. Magma-ice contact features are common. A dissected earlier cone underlies the E flank of Redoubt. Alunite-bearing debris flows to the SE, E and N suggest multiple flank collapses over Redoubt's history. Most recent eruptions occurred in 1966-68, and 1989-90. In March 2009, Redoubt erupted to produce pyroclastic flows, voluminous lahars, and tephra that fell over large portions of south-central Alaska. Regional and local air traffic was significantly disrupted, Anchorage airport was closed for over 12 hours, and oil production in Cook Inlet was halted for nearly five months. Unrest began in August, 2008 with reports of H2S odor. In late September, the Alaska Volcano Observatory (AVO)’s seismic network recorded periods of volcanic tremor. Throughout the fall, AVO noted increased fumarolic emissions and accompanying ice- and snow-melt on and around the 1990 dome, and gas measurements showed elevated H2S and CO2 emissions. On January 23, seismometers recorded 48 hrs of intermittent tremor and discrete, low-frequency to hybrid events. Over the next 6 weeks, seismicity waxed and waned, an estimated 5-6 million m3 of ice were lost due to melting, volcanic gas emissions increased, and debris flows emerged repeatedly from recently formed ice holes near the 1990 dome, located on the crater’s N (“Drift”) side. On March 15, a phreatic explosion deposited non-juvenile ash from a new vent in the summit ice cap just S of the 1990 dome. Ash from the explosion rose to ~4500 m above sea level (asl). The plume was accompanied by weak seismicity. The first magmatic explosion occurred on March 22. Over the next two weeks, more than 19 explosions destroyed at least two lava domes and produced ash plumes that reached 6-18 km asl. Tephra was deposited along variable azimuths including trace to minor amounts on Anchorage and Kenai Peninsula communities, and reached Fairbanks, ~800 km to the N. Several lahars were produced by explosive disruption and melting of the “Drift” glacier. The largest lahars followed explosions on March 23 and April 4 and inundated the Drift River valley to the coast, causing temporary evacuation of the Drift River Oil Terminal, ~40 km from the vent. Time-lapse images captured pyroclastic flows and lahars in the “Drift” glacier valley during several of the explosions. Ballistics and pyroclastic flow deposits were observed on the crater rim and upper glacier on the south flank. After April 4, the volcano moved into a non-explosive period of dome building. Lava dome growth was tracked by satellite and thermal imagery and photogrammetry from web-camera and overflight images. Between April 4-June 9, the extrusion rate ranged from 35 m3/sec to 4 m3/sec. Seismicity and volcanic gas emissions remained high during this period. Estimated dome volume in mid-June was 68 M m3. August data suggest no further dome growth.

  20. Aerial View of Mauna Loa Volcano, Hawaii

    USGS Hawaiian Volcano Observatory scientists monitor Mauna Loa, the largest active volcano on Earth. In this 1985 aerial photo, Mauna Loa looms above Kīlauea Volcano’s summit caldera (left center) and nearly obscures Hualālai in the far distance (upper right)....

  1. Volcano Preparedness

    MedlinePlus

    ... from a volcano. Mudflows and flash flooding, wildland fires, and even deadly hot ashflow can reach you even if you cannot see the volcano during an eruption. Avoid river valleys and low lying areas. Trying to watch an ...

  2. CSAV Deformation Module Field Trip on Kilauea Volcano

    Hawaiian Volcano Observatory geologist Michael Poland explaining to international volcano scientists that faulting in this area of Kilauea Volcano can be quantified by looking at the magnitude of fracture opening versus the age of lavas, and that 30 meters of extension has occurred in the past ~600 ...

  3. Nicaraguan Volcanoes

    Atmospheric Science Data Center

    2013-04-18

    article title:  Nicaraguan Volcanoes     View Larger Image Nicaraguan volcanoes, February 26, 2000 . The true-color image at left is a ... February 26, 2000 - Plumes from the San Cristobal and Masaya volcanoes. project:  MISR category:  gallery ...

  4. Predicting and validating the tracking of a Volcanic Ash Cloud during the 2006 Eruption of Mt. Augustine Volcano

    SciTech Connect

    Webley, Peter W.; Atkinson, D.; Collins, Richard L.; Dean, K.; Fochesatto, J.; Sassen, Kenneth; Cahill, Catherine F.; Prata, A.; Flynn, Connor J.; Mizutani, K.

    2008-11-01

    On 11 January 2006, Mount Augustine volcano in southern Alaska began erupting after 20-year repose. The Anchorage Forecast Office of the National Weather Service (NWS) issued an advisory on 28 January for Kodiak City. On 31 January, Alaska Airlines cancelled all flights to and from Anchorage after multiple advisories from the NWS for Anchorage and the surrounding region. The Alaska Volcano Observatory (AVO) had reported the onset of the continuous eruption. AVO monitors the approximately 100 active volcanoes in the Northern Pacific. Ash clouds from these volcanoes can cause serious damage to an aircraft and pose a serious threat to the local communities, and to transcontinental air traffic throughout the Arctic and sub-Arctic region. Within AVO, a dispersion model has been developed to track the dispersion of volcanic ash clouds. The model, Puff, was used operational by AVO during the Augustine eruptive period. Here, we examine the dispersion of a volcanic ash cloud from Mount Augustine across Alaska from 29 January through the 2 February 2006. We present the synoptic meteorology, the Puff predictions, and measurements from aerosol samplers, laser radar (or lidar) systems, and satellites. UAF aerosol samplers revealed the presence of volcanic aerosols at the surface at sites where Puff predicted the ash clouds movement. Remote sensing satellite data showed the development of the ash cloud in close proximity to the volcano and a sulfur-dioxide cloud further from the volcano consistent with the Puff predictions. Lidars showed the presence of volcanic aerosol with consistent characteristics aloft over Alaska and were capable of detecting the aerosol, even in the presence of scattered clouds and where the cloud is too thin/disperse to be detected by remote sensing satellite data. The lidar measurements revealed the different trajectories of ash consistent with the Puff predictions. Dispersion models provide a forecast of volcanic ash cloud movement that might be undetectable by any other means but are still a significant hazard. Validation is the key to assessing the accuracy of any future predictions. The study highlights the use of multiple and complementary observations used in detecting the trajectory ash cloud, both at the surface and aloft within the atmosphere.

  5. Galactic Super Volcano Similar to Iceland Volcano - Duration: 2 minutes, 2 seconds.

    NASA Video Gallery

    This composite image from NASAs Chandra X-ray Observatory with radio data from the Very Large Array shows a cosmic volcano being driven by a black hole in the center of the M87 galaxy. This eruptio...

  6. Interagency collaboration on an active volcano: a case study at Hawai‘i Volcanoes National Park

    USGS Publications Warehouse

    Kauahikaua, James P.; Orlando, Cindy

    2014-01-01

    Because Kilauea and Mauna Loa are included within the National Park, there is a natural intersection of missions for the National Park Service (NPS) and the U.S. Geological Survey (USGS). HAVO staff and the USGS Hawaiian Volcano Observatory scientists have worked closely together to monitor and forecast multiple eruptions from each of these volcanoes since HAVO’s founding in 1916.

  7. Alaska Seismic Network Upgrade and Expansion

    NASA Astrophysics Data System (ADS)

    Sandru, J. M.; Hansen, R. A.; Estes, S. A.; Fowler, M.

    2009-12-01

    AEIC (Alaska Earthquake Information Center) has begun the task of upgrading the older regional seismic monitoring sites that have been in place for a number of years. Many of the original sites (some dating to the 1960's) are still single component analog technology. This was a very reasonable and ultra low power reliable system for its day. However with the advanced needs of today's research community, AEIC has begun upgrading to Broadband and Strong Motion Seismometers, 24 bit digitizers and high-speed two-way communications, while still trying to maintain the utmost reliability and maintaining low power consumption. Many sites have been upgraded or will be upgraded from single component to triaxial broad bands and triaxial accerometers. This provided much greater dynamic range over the older antiquated technology. The challenge is compounded by rapidly changing digital technology. Digitizersand data communications based on analog phone lines utilizing 9600 baud modems and RS232 are becoming increasingly difficult to maintain and increasingly expensive compared to current methods that use Ethernet, TCP/IP and UDP connections. Gaining a reliable Internet connection can be as easy as calling up an ISP and having a DSL connection installed or may require installing our own satellite uplink, where other options don't exist. LANs are accomplished with a variety of communications devices such as spread spectrum 900 MHz radios or VHF radios for long troublesome shots. WANs are accomplished with a much wider variety of equipment. Traditional analog phone lines are being used in some instances, however 56K lines are much more desirable. Cellular data links have become a convenient option in semiurban environments where digital cellular coverage is available. Alaska is slightly behind the curve on cellular technology due to its low population density and vast unpopulated areas but has emerged into this new technology in the last few years. Partnerships with organizations such as ANSS, Alaska Volcano Observatory, Bradley Lake Dam, Red Dog Mine, The Plate Boundary Observatory (PBO), Alaska Tsunami Warning Center, and City and State Emergency Managers has helped link vast networks together so that the overall data transition can be varied. This lessens the likelihood of having a single point of failure for an entire network. Robust communication is key to retrieving seismic data. AEIC has gone through growing pains learning how to harden our network and encompassing the many types of telemetry that can be utilized in today's world. Redundant telemetry paths are a goal that is key to retrieving data, however at times this is not feasible with the vast size and terrain in Alaska. We will demonstrate what has worked for us and what our network consists of.

  8. An overview of the Icelandic Volcano Observatory response to the on-going rifting event at Bárðarbunga (Iceland) and the SO2 emergency associated with the gas-rich eruption in Holuhraun

    NASA Astrophysics Data System (ADS)

    Barsotti, Sara; Jonsdottir, Kristin; Roberts, Matthew J.; Pfeffer, Melissa A.; Ófeigsson, Benedikt G.; Vögfjord, Kristin; Stefánsdóttir, Gerður; Jónasdóttir, Elin B.

    2015-04-01

    On 16 August, 2014, Bárðarbunga volcano entered a new phase of unrest. Elevated seismicity in the area with up to thousands of earthquakes detected per day and significant deformation was observed around the Bárðarbunga caldera. A dike intrusion was monitored for almost two weeks until a small, short-lived effusive eruption began on 29 August in Holuhraun. Two days later a second, more intense, tremendously gas-rich eruption started that is still (as of writing) ongoing. The Icelandic Volcano Observatory (IVO), within the Icelandic Meteorological Office (IMO), monitors all the volcanoes in Iceland. Responsibilities include evaluating their related hazards, issuing warnings to the public and Civil Protection, and providing information regarding risks to aviation, including a weekly summary of volcanic activity provided to the Volcanic Ash Advisory Center in London. IVO has monitored the Bárðarbunga unrest phase since its beginning with the support of international colleagues and, in collaboration with the University of Iceland and the Environment Agency of Iceland, provides scientific support and interpretation of the ongoing phenomena to the local Civil Protection. The Aviation Color Code, for preventing hazards to aviation due to ash-cloud encounter, has been widely used and changed as soon as new observations and geophysical data from the monitoring network have suggested a potential evolution in the volcanic crisis. Since the onset of the eruption, IVO is monitoring the gas emission by using different and complementary instrumentations aimed at analyzing the plume composition as well as estimating the gaseous fluxes. SO2 rates have been measured with both real-time scanning DOASes and occasional mobile DOAS traveses, near the eruption site and in the far field. During the first month-and-a-half of the eruption, an average flux equal to 400 kg/s was registered, with peaks exceeding 1,000 kg/s. Along with these measurements the dispersal model CALPUFF has been initialized daily and run to provide the dispersal of the SO2 volcanic cloud across the country. Daily 72-hours forecasts of SO2 ground concentration are available on the IMO webpage. If critical concentration are expected in inhabited areas, the meteorologist on duty is in charge to promptly issuing a specific warning on the web. The IMO web-page has also been improved with a registration form, open to the public, for reporting SO2 contamination and poor air quality conditions due to the eruption. A long-term hazard assessment for the high concentrations of SO2 affecting the country has also been requested from IVO (IMO) by the Icelandic Civil Protection. For this purpose two hazard zoning maps, showing the areas potentially affected by specific concentration levels have been produced. The two maps have been constructed for probability of occurrence equaling 50% and 90%, respectively. Based on all these information and advices, the Civil Protection is taking decisions for what concerns precautionary measures like for example the limitation of accessibility to the eruption site, the evacuation of exposed areas, and the issuing of warnings and information for mitigating discomforts to inhabitants and tourists.

  9. In Brief: U.S. Volcano Early Warning System; Bill provides clear mandate for NOAA

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2005-05-01

    The U.S. Geological Survey on 29 April released a comprehensive review of the 169 U.S. volcanoes, and established a framework for a National Volcano Early Warning System that is being formulated by the Consortium of U.S. Volcano Observatories. The framework proposes an around-the-clock Volcano Watch Office and improved instrumentation and monitoring at targeted volcanoes. The report, authored by USGS scientists John Ewert, Marianne Guffanti, and Thomas Murray, notes that although a few U.S. volcanoes are well-monitored, half of the most threatening volcanoes are monitored at a basic level and some hazardous volcanoes have no ground-based monitoring.

  10. Ground surface deformation patterns, magma supply, and magma storage at Okmok volcano, Alaska, from InSAR analysis: 1. Intereruption deformation, 1997–2008

    USGS Publications Warehouse

    Lu, Zhong; Dzurisin, Daniel; Biggs, Juliet; Wicks, Charles, Jr.; McNutt, Steve

    2010-01-01

    Starting soon after the 1997 eruption at Okmok volcano and continuing until the start of the 2008 eruption, magma accumulated in a storage zone centered ~3.5 km beneath the caldera floor at a rate that varied with time. A Mogi-type point pressure source or finite sphere with a radius of 1 km provides an adequate fit to the deformation field portrayed in time-sequential interferometric synthetic aperture radar images. From the end of the 1997 eruption through summer 2004, magma storage increased by 3.2–4.5 × 107 m3, which corresponds to 75–85% of the magma volume erupted in 1997. Thereafter, the average magma supply rate decreased such that by 10 July 2008, 2 days before the start of the 2008 eruption, magma storage had increased by 3.7–5.2 × 107 m3 or 85–100% of the 1997 eruption volume. We propose that the supply rate decreased in response to the diminishing pressure gradient between the shallow storage zone and a deeper magma source region. Eventually the effects of continuing magma supply and vesiculation of stored magma caused a critical pressure threshold to be exceeded, triggering the 2008 eruption. A similar pattern of initially rapid inflation followed by oscillatory but generally slowing inflation was observed prior to the 1997 eruption. In both cases, withdrawal of magma during the eruptions depressurized the shallow storage zone, causing significant volcano-wide subsidence and initiating a new intereruption deformation cycle.

  11. Evidence of magma intrusion at Fourpeaked volcano, Alaska in 2006-2007 from a rapid-response seismic network and volcanic gases

    USGS Publications Warehouse

    Gardine, M.; West, M.; Werner, C.; Doukas, M.

    2011-01-01

    On September 17th, 2006, Fourpeaked volcano had a widely-observed phreatic eruption. At the time, Fourpeaked was an unmonitored volcano with no known Holocene activity, based on limited field work. Airborne gas sampling began within days of the eruption and a modest seismic network was installed in stages. Vigorous steaming continued for months; however, there were no further eruptions similar in scale to the September 17 event. This eruption was followed by several months of sustained seismicity punctuated by vigorous swarms, and SO2 emissions exceeding a thousand tons/day. Based on observations during and after the phreatic eruption, and assuming no recent pre-historical eruptive activity at Fourpeaked, we propose that the activity was caused by a minor injection of new magma at or near 5km depth beneath Fourpeaked, which remained active over several months as this magma equilibrated into the crust. By early 2007 declining seismicity and SO2 emission signaled the end of unrest. Because the Fourpeaked seismic network was installed in stages and the seismicity was punctuated by discrete swarms, we use Fourpeaked to illustrate quantitatively the efficacy and shortcomings of rapid response seismic networks for tracking volcanic earthquakes.

  12. What controls earthquakes at Aleutian arc volcanoes?

    NASA Astrophysics Data System (ADS)

    Buurman, H.; West, M. E.; Cameron, C.

    2012-12-01

    Alaska has around 100 Holocene active volcanoes spread over 3000 km of the Aleutian arc, from Mount Wrangell in southcentral Alaska to Buldir Island in the western Aleutian islands. The range in volcanic styles across the arc is as great as the distance that it spans, and so too is the accompanying volcano seismicity. This study examines whether there are systematic influences on volcano seismicity across the Aleutian arc that can account for distinctive patterns in earthquake behaviour, such as the paucity of deep (>20 km depth) volcanic earthquakes in the Cook Inlet region compared to volcanic earthquakes at the westernmost portion of the Alaska Peninsula. We investigate whether physical factors such as volcano size, geographic location relative to the subduction zone, the regional setting - including the type of crust and the distance between the vent and the ocean - and the local angle and rate of subduction affect volcano seismicity. We use continuous seismic data recorded over a 10-year period at 47 volcanoes to characterise patterns in seismicity. Our analyses consider the number and locations of hypocenters, waveform characteristics such as frequency content and magnitude, and the frequency and style of volcanic unrest during the study period.

  13. Redoubt Volcano

    Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula. The mushroom-shaped plume rose from avalanches of hot debris (pyroclastic flows) that cascaded down the north flank of the volcano. A smaller, white steam plume rises from the summit crater. ...

  14. 2009 ERUPTION OF REDOUBT VOLCANO: Lahars, Oil, and the Role of Science in Hazards Mitigation (Invited)

    NASA Astrophysics Data System (ADS)

    Swenson, R.; Nye, C. J.

    2009-12-01

    In March, 2009, Redoubt Volcano erupted for the third time in 45 years. More than 19 explosions produced ash plumes to 60,000 ft asl, lahar flows of mud and ice down the Drift river ~30 miles to the coast, and tephra fall up to 1.5 mm onto surrounding communities. The eruption had severe impact on many operations. Airlines were forced to cancel or divert hundreds of international and domestic passenger and cargo flights, and Anchorage International airport closed for over 12 hours. Mudflows and floods down the Drift River to the coast impacted operations at the Drift River Oil Terminal (DROT) which was forced to shut down and ultimately be evacuated. Prior mitigation efforts to protect the DROT oil tank farm from potential impacts associated with a major eruptive event were successful, and none of the 148,000 barrels of oil stored at the facility was spilled or released. Nevertheless, the threat of continued eruptive activity at Redoubt, with the possibility of continued lahar flows down the Drift River alluvial fan, required an incident command post be established so that the US Coast Guard, Alaska Dept. of Environmental Conservation, and the Cook Inlet Pipeline Company could coordinate a response to the potential hazards. Ultimately, the incident command team relied heavily on continuous real-time data updates from the Alaska Volcano Observatory, as well as continuous geologic interpretations and risk analysis by the USGS Volcanic Hazards group, the State Division of Geological and Geophysical Surveys and the University of Alaska Geophysical Institute, all members of the collaborative effort of the Alaska Volcano Observatory. The great success story that unfolded attests to the efforts of the incident command team, and their reliance on real-time scientific analysis from scientific experts. The positive results also highlight how pre-disaster mitigation and monitoring efforts, in concert with hazards response planning, can be used in a cooperative industry / multi-agency effort to positively affect hazards mitigation. The final outcomes from this potentially disastrous event included: 1) no on-site personnel were injured; 2) no detrimental environmental impacts associated with the oil terminal occurred; and 3) incident command personnel, together with numerous industry representatives, were able to make well-informed, although costly decisions that resulted in safe removal of the oil from the storage facilities. The command team’s efforts also furthered the process of restarting the Cook Inlet oil production after a forced five month shutdown.

  15. Earthquake classification, location, and error analysis in a volcanic environment: implications for the magmatic system of the 1989-1990 eruptions at redoubt volcano, Alaska

    USGS Publications Warehouse

    Lahr, J.C.; Chouet, B.A.; Stephens, C.D.; Power, J.A.; Page, R.A.

    1994-01-01

    Determination of the precise locations of seismic events associated with the 1989-1990 eruptions of Redoubt Volcano posed a number of problems, including poorly known crustal velocities, a sparse station distribution, and an abundance of events with emergent phase onsets. In addition, the high relief of the volcano could not be incorporated into the hypoellipse earthquake location algorithm. This algorithm was modified to allow hypocenters to be located above the elevation of the seismic stations. The velocity model was calibrated on the basis of a posteruptive seismic survey, in which four chemical explosions were recorded by eight stations of the permanent network supplemented with 20 temporary seismographs deployed on and around the volcanic edifice. The model consists of a stack of homogeneous horizontal layers; setting the top of the model at the summit allows events to be located anywhere within the volcanic edifice. Detailed analysis of hypocentral errors shows that the long-period (LP) events constituting the vigorous 23-hour swarm that preceded the initial eruption on December 14 could have originated from a point 1.4 km below the crater floor. A similar analysis of LP events in the swarm preceding the major eruption on January 2 shows they also could have originated from a point, the location of which is shifted 0.8 km northwest and 0.7 km deeper than the source of the initial swarm. We suggest this shift in LP activity reflects a northward jump in the pathway for magmatic gases caused by the sealing of the initial pathway by magma extrusion during the last half of December. Volcano-tectonic (VT) earthquakes did not occur until after the initial 23-hour-long swarm. They began slowly just below the LP source and their rate of occurrence increased after the eruption of 01:52 AST on December 15, when they shifted to depths of 6 to 10 km. After January 2 the VT activity migrated gradually northward; this migration suggests northward propagating withdrawal of magma from a plexus of dikes and/or sills located in the 6 to 10 km depth range. Precise relocations of selected events prior to January 2 clearly resolve a narrow, steeply dipping, pencil-shaped concentration of activity in the depth range of 1-7 km, which illuminates the conduit along which magma was transported to the surface. A third event type, named hybrid, which blends the characteristics of both VT and LP events, originates just below the LP source, and may reflect brittle failure along a zone intersecting a fluid-filled crack. The distribution of hybrid events is elongated 0.2-0.4 km in an east-west direction. This distribution may offer constraints on the orientation and size of the fluid-filled crack inferred to be the source of the LP events. ?? 1994.

  16. Eruption dynamics of the 7.7 ka Driftwood pumice-fall suggest mafic injection is a common eruption mechanism for Makushin Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Lerner, A.; Crowley, P.; Hazlett, R. W.; Nicolaysen, K. E.

    2010-12-01

    Makushin Volcano on Unalaska Island, AK is potentially the most threatening volcano in the Aleutian chain, being close to the largest Aleutian towns of Dutch Harbor and Unalaska. This study reports the eruption chronology and triggering mechanism for the most recent highly explosive event, the 7.7 ka Driftwood Pumice-fall event. The Driftwood Pumice reaches thicknesses of over 2 m, and isopach contours estimate a total deposit volume of 0.3-0.9 km3, covering an area of at least 8100 km2. These reconstructions show an eruption on the scale of the 1980 Mt. St. Helens eruption, with a VEI of 4-5. In the field, the deposit was divided into four stratigraphic horizons from bottom to top, and tephra within these layers becomes systematically more mafic upward through the section, ranging from a basal low-SiO2 dacite (64 wt.% SiO2) to an upper medium-SiO2 andesite (61.5 wt.% SiO2). High-Ca plagioclase (An75-83) and high-Mg olivine (Mg69-75) grains within the pumice are in great disequilibrium with the dacitic glass (64-69 wt.% SiO2), suggesting their origin in a more mafic magma. Geochemical trends, disequilibrium mineral populations, and mineral zonation patterns within these plagioclase and olivine xenocrysts show evidence of magma mixing between a bulk siliceous magma chamber and a mafic injection. The amount of the mafic component increases upward within the deposit, ranging from 0-25% throughout the section. The mafic injection is calculated to have been ~110-200 °C hotter than the siliceous magma chamber. The thermal pulse provided by the injection likely initiated convection and volatile exsolution within the siliceous magma body, ultimately causing the Driftwood Pumice eruption. Diffusion rates based on the thickness of lower-Mg rim zonations (<10 µm thick rims of Mg64) in the olivine xenocrysts show a lag-time of ~1 year between the basaltic injection and the resulting eruption. Similar delays between mafic injections and eruptions are seen in numerous other volcanic systems where magma mixing has been cited as the eruption trigger. The Driftwood Pumice is stratigraphically sandwiched between numerous smaller ashfalls, many of which consist of light-dark ash couplets. The color and compositional differences between the layers of these ash couplets are similar to differences within the Driftwood Pumice horizons, though the Driftwood Pumice is significantly thicker than the couplets. The repeated occurrences of light tephra overlain by dark, more mafic tephra suggest that magma mixing via a mafic injection is a common mechanism for sparking Makushin eruptions.

  17. Active Monitoring for Active Volcanoes - A challenge at Sakurajima volcano

    NASA Astrophysics Data System (ADS)

    Yamaoka, K.; Watanabe, T.; Michishita, T.; Miyamachi, H.; Iguchi, M.

    2011-12-01

    Quantitative monitoring of magma transport process is essentially important for understanding the volcanic process and prediction of volcanic eruptions. To realize this monitoring, a project, deployment of an active source called ACROSS in Sakurajima volcano, is being underway. In this study, we assessed the feasibility of the capability of monitoring using ACROSS vibrator system for Sakurajima volcano in terms of detectability of signal and its temporal variation due to reasonable change in volcanic structure. Sakurajima volcano is one of the most active volcanoes in the world, which erupts more than a thousand times in 2010, and has been intensively monitored by a research observatory. We chose Sakurajima volcano as a first test site for volcano monitoring with ACROSS because of its well-deployed seismic network and repeating volcanic eruptions. First we assess the signal-to-noise ratio (SNR) for the case in which we use the same source as deployed in the Tokai area. The detectability of temporal change in the signal from the source is simply dependent on the SNR at the receivers. As the SNR increases with the length of data-stacking, we estimate the reasonable stacking length and the distance range that ACROSS signal can be recorded with enough SNR. We use a general distance dependent attenuation model including geometrical spreading and internal energy dissipation to estimate the parameters describing source strength and internal energy dissipation. We use a attenuation relation that is estimated by existing ACROSS source in the Tokai area to estimate the source strength. As for the internal energy dissipation we use the data of explosion experiment that was carried out around Sakurajima volcano in 2008. The result shows that the signal of an ACROSS vibrator can be recorded with good SNR for the whole area of Sakurajima island for the staking length of 3 months. Next we assess the effect of attenuation (Q) on the detectability of structure change for the realistic volcano structure. We created a structure model of Sakurajima volcano with existing structure model and calculated the change in spectral signal by a small change of structure model. The result shows that the low-Q nature of volcano has little effect on the ACROSS signal in low frequency band (3.5-7.5Hz). These results will be compared with the actual observation experiment in the coming years. Acknowledgement: We use the data-set of the exploration experiment in Sakurajima volcano which is carried out by Volcano eruption prediction group in 2008.

  18. Cascade Volcanoes

    The volcanoes from closest to farthest are Mt. Washington, Three Fingered Jack, Mt. Jefferson. This picture is taken from Middle Sister looking north in the Cascade Range, Three Sisters Wilderness Area, Deschutes National Forest, Oregon....

  19. Observations of deep long-period (DLP) seismic events beneath Aleutian arc volcanoes; 1989 2002

    NASA Astrophysics Data System (ADS)

    Power, J. A.; Stihler, S. D.; White, R. A.; Moran, S. C.

    2004-12-01

    Between October 12, 1989 and December 31, 2002, the Alaska Volcano Observatory (AVO) located 162 deep long-period (DLP) events beneath 11 volcanic centers in the Aleutian arc. These events generally occur at mid- to lower-crustal depths (10-45 km) and are characterized by emergent phases, extended codas, and a strong spectral peak between 1.0 and 3.0 Hz. Observed wave velocities and particle motions indicate that the dominant phases are P- and S-waves. DLP epicenters often extend over broad areas (5-20 km) surrounding the active volcanoes. The average reduced displacement of Aleutian DLPs is 26.5 cm 2 and the largest event has a reduced displacement of 589 cm 2 (or ML 2.5). Aleutian DLP events occur both as solitary events and as sequences of events with several occurring over a period of 1-30 min. Within the sequences, individual DLPs are often separated by lower-amplitude volcanic tremor with a similar spectral character. Occasionally, volcano-tectonic earthquakes that locate at similar depths are contained within the DLP sequences. At most, Aleutian volcanoes DLPs appear to loosely surround the main volcanic vent and occur as part of background seismicity. A likely explanation is that they reflect a relatively steady-state process of magma ascent over broad areas in the lower and middle portions of the crust. At Mount Spurr, DLP seismicity was initiated by the 1992 eruptions and then slowly declined until 1997. At Shishaldin Volcano, a short-lived increase in DLP seismicity occurred about 10 months prior to the April 19, 1999 eruption. These observations suggest a link between eruptive activity and magma flux in the mid- to lower-crust and uppermost mantle.

  20. Ground surface deformation patterns, magma supply, and magma storage at Okmok volcano, Alaska, from InSAR analysis: 2. Coeruptive deflation, July-August 2008

    USGS Publications Warehouse

    Lu, Zhong; Dzurisin, Daniel

    2010-01-01

    A hydrovolcanic eruption near Cone D on the floor of Okmok caldera, Alaska, began on 12 July 2008 and continued until late August 2008. The eruption was preceded by inflation of a magma reservoir located beneath the center of the caldera and ~3 km below sea level (bsl), which began immediately after Okmok's previous eruption in 1997. In this paper we use data from several radar satellites and advanced interferometric synthetic aperture radar (InSAR) techniques to produce a suite of 2008 coeruption deformation maps. Most of the surface deformation that occurred during the eruption is explained by deflation of a Mogi-type source located beneath the center of the caldera and 2–3 km bsl, i.e., essentially the same source that inflated prior to the eruption. During the eruption the reservoir deflated at a rate that decreased exponentially with time with a 1/e time constant of ~13 days. We envision a sponge-like network of interconnected fractures and melt bodies that in aggregate constitute a complex magma storage zone beneath Okmok caldera. The rate at which the reservoir deflates during an eruption may be controlled by the diminishing pressure difference between the reservoir and surface. A similar mechanism might explain the tendency for reservoir inflation to slow as an eruption approaches until the pressure difference between a deep magma production zone and the reservoir is great enough to drive an intrusion or eruption along the caldera ring-fracture system.

  1. Evaluation of gases, condensates, and SO2 emissions from Augustine volcano, Alaska: the degassing of a Cl-rich volcanic system

    USGS Publications Warehouse

    Symonds, R.B.; Rose, William I., Jr.; Gerlach, T.M.; Briggs, P.H.; Harmon, R.S.

    1990-01-01

    After the March-April 1986 explosive eruption a comprehensive gas study at Augustine was undertaken in the summers of 1986 and 1987. Airborne COSPEC measurements indicate that passive SO2 emission rates declined exponentially during this period from 380??45 metric tons/day (T/D) on 7/24/86 to 27??6 T/D on 8/24/87. These data are consistent with the hypothesis that the Augustine magma reservoir has become more degassed as volcanic activity decreased after the spring 1986 eruption. Gas samples collected in 1987 from an 870??C fumarole on the andesitic lava dome show various degrees of disequilibrium due to oxidation of reduced gas species and condensation (and loss) of H2O in the intake tube of the sampling apparatus. Thermochemical restoration of the data permits removal of these effects to infer an equilibrium composition of the gases. Although not conclusive, this restoration is consistent with the idea that the gases were in equilibrium at 870??C with an oxygen fugacity near the Ni-NiO buffer. These restored gas compositions show that, relative to other convergent plate volcanoes, the Augustine gases are very HCl rich (5.3-6.0 mol% HCl), S rich (7.1 mol% total S), and H2O poor (83.9-84.8 mol% H2O). Values of ??D and ??18O suggest that the H2O in the dome gases is a mixture of primary magmatic water (PMW) and local seawater. Part of the Cl in the Augustine volcanic gases probably comes from this shallow seawater source. Additional Cl may come from subducted oceanic crust because data by Johnston (1978) show that Cl-rich glass inclusions in olivine crystals contain hornblende, which is evidence for a deep source (>25km) for part of the Cl. Gas samples collected in 1986 from 390??-642??C fumaroles on a ramp surrounding the inner summit crater have been oxidized so severely that restoration to an equilibrium composition is not possible. H and O isotope data suggest that these gases are variable mixtures of seawater, FMW, and meteoric steam. These samples are much more H2O-rich (92%-97% H2O) than the dome gases, possibly due to a larger meteoric steam component. The 1986 samples also have higher Cl/S, S/C, and F/Cl ratios, which imply that the magmatic component in these gases is from the more degassed 1976 magma. Thus, the 1987 samples from the lava dome are better indicators than the 1986 samples of degassing within the Augustine magma reservoir, even though they were collected a year later and contain a significant seawater component. Future gas studies at Augustine should emphasize fumaroles on active lava domes. Condensates collected from the same lava-dome fumarole have enrichments ot 107-102 in Cl, Br, F, B, Cd, As, S, Bi, Pb, Sb, Mo, Zn, Cu, K, Li, Na, Si, and Ni. Lower-temperature (200??-650??C) fumaroles around the volcano are generally less enriched in highly volatile elements. However, these lower-termperature fumaroles have higher concentration of rock-forming elements, probably derived from the wall rock. ?? 1990 Springer-Verlag.

  2. WIYN Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Located at Kitt Peak in Arizona. The WIYN Observatory is owned and operated by the WIYN Consortium, which consists of the University of Wisconsin, Indiana University, Yale University and the National Optical Astronomy Observatories (NOAO). Most of the capital costs of the observatory were provided by these universities, while NOAO, which operates the other telescopes of the KITT PEAK NATIONAL OBS...

  3. Character, mass, distribution, and origin of tephra-fall deposits of the 1989-1990 eruption of redoubt volcano, south-central Alaska

    USGS Publications Warehouse

    Scott, W.E.; McGimsey, R.G.

    1994-01-01

    The 1989-1990 eruption of Redoubt Volcano spawned about 20 areally significant tephra-fall deposits between December 14, 1989 and April 26, 1990. Tephra plumes rose to altitudes of 7 to more than 10 km and were carried mainly northward and eastward by prevailing winds, where they substantially impacted air travel, commerce, and other activities. In comparison to notable eruptions of the recent past, the Redoubt events produced a modest amount of tephra-fall deposits - 6 ?? 107 to 5 ?? 1010 kg for individual events and a total volume (dense-rock equivalent) of about 3-5 ?? 107 m3 of andesite and dacite. Two contrasting tephra types were generated by these events. Pumiceous tephra-fall deposits of December 14 and 15 were followed on December 16 and all later events by fine-grained lithic-crystal tephra deposits, much of which fell as particle aggregates. The change in the character of the tephra-fall deposits reflects their fundamentally different modes of origin. The pumiceous deposits were produced by magmatically driven explosions. The finegrained lithic-crystal deposits were generated by two processes. Hydrovolcanic vent explosions generated tephrafall deposits of December 16 and 19. Such explosions continued as a tephra source, but apparently with diminishing importance, during events of January and February. Ash clouds of lithic pyroclastic flows generated by collapse of actively growing lava domes probably contributed to tephra-fall deposits of all events from January 2 to April 26, and were the sole source of tephra fall for at least the last 4 deposits. ?? 1994.

  4. Geomagnetic variation related to Sakurajima volcano eruption

    NASA Astrophysics Data System (ADS)

    Kim, K.; Lee, C. W.

    2014-12-01

    Geomagnetic field has been studied for measuring precursor signals to understand earthquake events by geoscientists. Furthermore, analysis of geomagnetic data helps detect symptom of volcanic eruption. In this study, we process geomagnetic data for Sakurajima volcano case which erupted on Aug 18, 2013 with a large scale of eruption in Japan. This volcanic activity has an effect on geomagnetic data not only geomagnetic observatory in Japan but also in Korea. This study carries out that the geomagnetic variation has been analyzed using geomagnetic data from Cheongyang observatory in Korea and several geomagnetic observatories in Japan. First, we compared the geomagnetic data directly from each component, then searching the difference by volcanic eruption. Secondly, we execute wavelet based semblance from geomagnetic data in order to confirm the correlation between geomagnetic data and effect from volcano activity. As a result, geomagnetic diurnal variation is generally about 50 nT. However, It hardly shows geomagnetic variation on z component and displays about 15 nT on total component before Sakurajima volcano eruption at Kanoya geomagnetic observatory. Moreover, we could confirm uncorrelated event by wavelet based semblance analysis what estimated to volcano activity. This study conducted to confirm geomagnetic variation related to volcano activity getting meaningful result.

  5. The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results

    USGS Publications Warehouse

    Schaefer, J.R.; Scott, W.E.; Evans, William C.; Jorgenson, J.; McGimsey, R.G.; Wang, B.

    2008-01-01

    A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated 3.8??106 m3 of sulfurous, clay-rich debris and acidic water, with an accompanying acidic aerosol component, exited the crater through a tunnel at the base of a glacier that breaches the south crater rim. Over 27 km downstream, the acidic waters of the flood inundated an important salmon spawning drainage, acidifying Mother Goose Lake from surface to depth (approximately 0.5 km3 in volume at a pH of 2.9 to 3.1), killing all aquatic life, and preventing the annual salmon run. Over 2 months later, crater lake water sampled 8 km downstream of the outlet after considerable dilution from glacial meltwater was a weak sulfuric acid solution (pH = 3.2, SO4 = 504 mg/L, Cl = 53.6 mg/L, and F = 7.92 mg/L). The acid flood waters caused severe vegetation damage, including plant death and leaf kill along the flood path. The crater lake drainage was accompanied by an ambioructic flow of acidic aerosols that followed the flood path, contributing to defoliation and necrotic leaf damage to vegetation in a 29 km2 area along and above affected streams, in areas to heights of over 150 m above stream level. Moss species killed in the event contained high levels of sulfur, indicating extremely elevated atmospheric sulfurcontent. The most abundant airborne phytotoxic constituent was likely sulfuric acid aerosols that were generated during the catastrophic partial crater lake drainage event. Two mechanisms of acidic aerosol formation are proposed: (1) generation of aerosol mist through turbulent flow of acidic water and (2) catastrophic gas exsolution. This previously undocumented phenomenon of simultaneous vegetationdamaging acidic aerosols accompanying drainage of an acidic crater lake has important implications for the study of hazards associated with active volcanic crater lakes. Copyright 2008 by the American Geophysical Union.

  6. The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results

    NASA Astrophysics Data System (ADS)

    Schaefer, Janet R.; Scott, William E.; Evans, William C.; Jorgenson, Janet; McGimsey, Robert G.; Wang, Bronwen

    2008-07-01

    A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated 3.8 × 106 m3 of sulfurous, clay-rich debris and acidic water, with an accompanying acidic aerosol component, exited the crater through a tunnel at the base of a glacier that breaches the south crater rim. Over 27 km downstream, the acidic waters of the flood inundated an important salmon spawning drainage, acidifying Mother Goose Lake from surface to depth (approximately 0.5 km3 in volume at a pH of 2.9 to 3.1), killing all aquatic life, and preventing the annual salmon run. Over 2 months later, crater lake water sampled 8 km downstream of the outlet after considerable dilution from glacial meltwater was a weak sulfuric acid solution (pH = 3.2, SO4 = 504 mg/L, Cl = 53.6 mg/L, and F = 7.92 mg/L). The acid flood waters caused severe vegetation damage, including plant death and leaf kill along the flood path. The crater lake drainage was accompanied by an ambioructic flow of acidic aerosols that followed the flood path, contributing to defoliation and necrotic leaf damage to vegetation in a 29 km2 area along and above affected streams, in areas to heights of over 150 m above stream level. Moss species killed in the event contained high levels of sulfur, indicating extremely elevated atmospheric sulfur content. The most abundant airborne phytotoxic constituent was likely sulfuric acid aerosols that were generated during the catastrophic partial crater lake drainage event. Two mechanisms of acidic aerosol formation are proposed: (1) generation of aerosol mist through turbulent flow of acidic water and (2) catastrophic gas exsolution. This previously undocumented phenomenon of simultaneous vegetation-damaging acidic aerosols accompanying drainage of an acidic crater lake has important implications for the study of hazards associated with active volcanic crater lakes.

  7. Observation of volcanoes through webcams: Tools and techniques

    NASA Astrophysics Data System (ADS)

    Lovick, J.; Lawlor, O.; Dean, K.; Dehn, J.

    2008-12-01

    This work explores techniques for deriving quantitative data from webcam observations. It illustrates the role that webcams can play in volcano monitoring, and shows our recently developed tools for the collation and dissemination of this data. Over the past 5 years, digital cameras have been installed at a number of volcanoes to allow the general public to see volcanic activity from the comfort of their own homes. In the last 3 years these webcam images have become part of the twice-daily volcano monitoring report by the remote sensing team of the Alaska Volcano Observatory (AVO). To allow comprehensive and systematic analysis, a database has been created containing all AVO webcam images as well as images from St. Helens and three KVERT webcams for Bezymianny, Klyucheskoy and Shiveluch. In total, some 1.6 million images are currently held. The number increases daily as new images are obtained and processed. The database holds additional information about each image such as both image-wide and localized-region statistics. Our tools have been developed to answer specific questions utilizing this data. Of the current 1.6 million images in the database, a very small percentage is considered interesting for volcano monitoring; the remainder can be ignored due to complete cloud cover or (for nocturnal images) lack of luminescence. We have developed a tool for automatically isolating uninteresting images (primarily based on image histograms.) Uninteresting images are tagged, which allows for them to be excluded from further processing. Our next tool is an automated system for isolating and measuring nocturnal luminescence. This tool has been developed using images of St. Helens and is being extended to work with other webcams where nightime lava glow have been seen. The system works by first minimizing each camera's unique dark current and amplification noise signals and then establishes if any pixels fulfill a number of criteria that would indicate they are real "glow" pixels. A third tool integrates the webcam data into Google Earth, allowing the height of plumes to be easily estimated and also the location of features on the sides of the volcano to be accurately placed on to the ground/GoogleMap surface. This tool makes visualization of multiple webcams of a single volcano easy. The recent eruptive phase of St. Helens has prompted the development of a system for measuring 'dome growth'. A technique using stacks of images and the Irani-Peleg super-resolution algorithm to estimate subpixel region growth is being tested at the moment. The final tool presented (currently under development) is a simple volcanic plume finder. It works by analyzing the RGB histograms of key regions around the volcano vent and flagging image statistics which indicate the possible presence of steam. It is postulated that when adjusted for local climatic conditions the amount of steaming may be indicative of change at a volcano. These techinques aim to move the analysis of webcam images into an operational framework on a sound scientific footing.

  8. Catalogue of Icelandic volcanoes

    NASA Astrophysics Data System (ADS)

    Ilyinskaya, Evgenia; Larsen, Gudrun; Vogfjörd, Kristin; Tumi Gudmundsson, Magnus; Jonsson, Trausti; Oddsson, Björn; Reynisson, Vidir; Barsotti, Sara; Karlsdottir, Sigrun

    2015-04-01

    Volcanic activity in Iceland occurs on volcanic systems that usually comprise a central volcano and fissure swarm. Over 30 systems have been active during the Holocene. In the last 100 years, over 30 eruptions have occurred displaying very varied activity in terms of eruption styles, eruptive environments, eruptive products and their distribution. Although basaltic eruptions are most common, the majority of eruptions are explosive, not the least due to magma-water interaction in ice-covered volcanoes. Extensive research has taken place on Icelandic volcanism, and the results reported in scientific papers and other publications. In 2010, the International Civil Aviation Organisation funded a 3 year project to collate the current state of knowledge and create a comprehensive catalogue readily available to decision makers, stakeholders and the general public. The work on the Catalogue began in 2011, and was then further supported by the Icelandic government and the EU. The Catalogue forms a part of an integrated volcanic risk assessment project in Iceland (commenced in 2012), and the EU FP7 project FUTUREVOLC (2012-2016), establishing an Icelandic volcano Supersite. The Catalogue is a collaborative effort between the Icelandic Meteorological Office (the state volcano observatory), the Institute of Earth Sciences at the University of Iceland, and the Icelandic Civil Protection, with contributions from a large number of specialists in Iceland and elsewhere. The catalogue is scheduled for opening in the first half of 2015 and once completed, it will be an official publication intended to serve as an accurate and up to date source of information about active volcanoes in Iceland and their characteristics. The Catalogue is an open web resource in English and is composed of individual chapters on each of the volcanic systems. The chapters include information on the geology and structure of the volcano; the eruption history, pattern and products; the known precursory signals and current monitoring level; associated hazards; and detailed descriptions of possible eruption scenarios. Where data allows, the likelihood of different eruption scenarios will also be depicted by probabilistic event trees. The chapters are illustrated with a number of figures, interactive maps and photographs.

  9. Chilean Volcanoes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On the border between Chile and the Catamarca province of Argentina lies a vast field of currently dormant volcanoes. Over time, these volcanoes have laid down a crust of magma roughly 2 miles (3.5 km) thick. It is tinged with a patina of various colors that can indicate both the age and mineral content of the original lava flows. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on May 15, 1999. This is a false-color composite image made using shortwave infrared, infrared, and green wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch

  10. Digital data set of volcano hazards for active Cascade Volcanos, Washington

    USGS Publications Warehouse

    Schilling, Steve P.

    1996-01-01

    Scientists at the Cascade Volcano Observatory have completed hazard assessments for the five active volcanos in Washington. The five studies included Mount Adams (Scott and others, 1995), Mount Baker (Gardner and others, 1995), Glacier Peak (Waitt and others, 1995), Mount Rainier (Hoblitt and others, 1995) and Mount St. Helens (Wolfe and Pierson, 1995). Twenty Geographic Information System (GIS) data sets have been created that represent the hazard information from the assessments. The twenty data sets have individual Open File part numbers and titles

  11. Eruption Forecasting: Success and Surprise at Kasatochi and Okmok Volcanoes

    NASA Astrophysics Data System (ADS)

    Prejean, S.; Power, J.; Brodsky, E.

    2008-12-01

    In the summer of 2008, the Alaska Volcano Observatory (AVO) successfully forecast eruption at an unmonitored volcano, Kasatochi, and was unable to forecast eruption at a well monitored volcano, Okmok. We use these case studies to explore the limitations and opportunities of seismically monitored and unmonitored systems and to evaluate situations when we can expect to succeed and when we must expect to fail in eruption forecasting. Challenges in forecasting eruptions include interpreting seismicity in context of volcanic history, developing a firm understanding of distance scales over which pre- and co-eruptive seismic signals are observed, and improving our ability to discriminate processes causing tremor. Kasatochi Volcano is a 3 km wide island in the central Aleutian Islands with no confirmed historical activity. Little is known about the eruptive history of the volcano. It was not considered an immediate threat until 3 days prior to eruption. A report of ground shaking by a biology field crew on the island on August 4 was the first indication of unrest. On August 6 a vigorous seismic swarm became apparent on the nearest seismic stations 40 km distant. The aviation color code/volcano alert level at Kasatochi was increased to Yellow/Advisory in response to increasing magnitude and frequency of earthquakes. The color code/alert level was increased to Orange/Watch on August 7 when volcanic tremor was observed in the wake of the largest earthquake in the sequence, a M 5.6. Three hours after the onset of volcanic tremor, eruption was confirmed by satellite data and the color code/alert level increased to Red/Warning. Eruption forecasting was possible only due to the exceptionally large moment release of pre-eruptive seismicity. The key challenge in evaluating the situation was distinguishing between tectonic activity and a volcanic swarm. It is likely there were weeks to months of precursory seismicity, however little instrumental record exists due to the lack of a seismic network on Kasatochi Island. Unlike Kasatochi, Okmok volcano, also located in the central Aleutian Islands, hosts 13 telemetered seismic stations and several telemetered GPS stations. The volcano has received considerable study by AVO, and the record of historical eruptions is well known. Despite regular scrutiny of Okmok data, the 2008 eruption was a surprise as there were fewer than 3 hours of clear pre-eruptive seismicity. The color code/alert level at Okmok went directly from Green/Normal to Red/Warning on July 12 after eruptive activity began. Interpretation of co-eruptive seismicity remained a challenge through the course of the eruption as bursts of volcanic tremor often did not correlate immediately with ash output at the vent as observed in satellite data.

  12. Gulf of Alaska, Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This MODIS true-color image shows the Gulf of Alaska and Kodiak Island, the partially snow-covered island in roughly the center of the image. Credit: Jacques Descloitres, MODIS Land Rapid Response Team

  13. Astronomical observatories

    NASA Technical Reports Server (NTRS)

    Ponomarev, D. N.

    1983-01-01

    The layout and equipment of astronomical observatories, the oldest scientific institutions of human society are discussed. The example of leading observatories of the USSR allows the reader to familiarize himself with both their modern counterparts, as well as the goals and problems on which astronomers are presently working.

  14. Observatories: History

    NASA Astrophysics Data System (ADS)

    Krisciunas, K.; Murdin, P.

    2000-11-01

    An astronomical OBSERVATORY is a building, installation or institution dedicated to the systematic and regular observation of celestial objects for the purpose of understanding their physical nature, or for purposes of time reckoning and keeping the calendar. At a bona fide observatory such work constitutes a main activity, not just an incidental one. While the ancient Egyptians, Babylonians, Chi...

  15. Integrating SAR and derived products into operational volcano monitoring and decision support systems

    NASA Astrophysics Data System (ADS)

    Meyer, F. J.; McAlpin, D. B.; Gong, W.; Ajadi, O.; Arko, S.; Webley, P. W.; Dehn, J.

    2015-02-01

    Remote sensing plays a critical role in operational volcano monitoring due to the often remote locations of volcanic systems and the large spatial extent of potential eruption pre-cursor signals. Despite the all-weather capabilities of radar remote sensing and its high performance in monitoring of change, the contribution of radar data to operational monitoring activities has been limited in the past. This is largely due to: (1) the high costs associated with radar data; (2) traditionally slow data processing and delivery procedures; and (3) the limited temporal sampling provided by spaceborne radars. With this paper, we present new data processing and data integration techniques that mitigate some of these limitations and allow for a meaningful integration of radar data into operational volcano monitoring decision support systems. Specifically, we present fast data access procedures as well as new approaches to multi-track processing that improve near real-time data access and temporal sampling of volcanic systems with SAR data. We introduce phase-based (coherent) and amplitude-based (incoherent) change detection procedures that are able to extract dense time series of hazard information from these data. For a demonstration, we present an integration of our processing system with an operational volcano monitoring system that was developed for use by the Alaska Volcano Observatory (AVO). Through an application to a historic eruption, we show that the integration of SAR into systems such as AVO can significantly improve the ability of operational systems to detect eruptive precursors. Therefore, the developed technology is expected to improve operational hazard detection, alerting, and management capabilities.

  16. Living on Active Volcanoes - The Island of Hawai'i

    USGS Publications Warehouse

    Heliker, Christina; Stauffer, Peter H.; Hendley, James W., II

    1997-01-01

    People on the Island of Hawai'i face many hazards that come with living on or near active volcanoes. These include lava flows, explosive eruptions, volcanic smog, damaging earthquakes, and tsunamis (giant seawaves). As the population of the island grows, the task of reducing the risk from volcano hazards becomes increasingly difficult. To help protect lives and property, U.S. Geological Survey (USGS) scientists at the Hawaiian Volcano Observatory closely monitor and study Hawai'i's volcanoes and issue timely warnings of hazardous activity.

  17. Smithsonian Volcano Data on Google Earth

    NASA Astrophysics Data System (ADS)

    Venzke, E.; Siebert, L.; Luhr, J. F.

    2006-12-01

    Interactive global satellite imagery datasets such as hosted by Google Earth provide a dynamic platform for educational outreach in the Earth Sciences. Users with widely varied backgrounds can easily view geologic features on a global-to-local scale, giving access to educational background on individual geologic features or events such as volcanoes and earthquakes. The Smithsonian Institution's Global Volcanism Program (GVP) volcano data became available as a Google Earth layer on 11 June 2006. Locations for about 1550 volcanoes with known or possible Holocene activity are shown as red triangles with associated volcano names that appear when zooming in to a regional-scale view. Clicking on a triangle opens an informational balloon that displays a photo, geographic data, and a brief paragraph summarizing the volcano's geologic history. The balloon contains links to a larger version of the photo with credits and a caption and to more detailed information on the volcano, including eruption chronologies, from the GVP website. Links to USGS and international volcano observatories or other websites focusing on regional volcanoes are also provided, giving the user ready access to a broad spectrum of volcano data. Updates to the GVP volcano layer will be provided to Google Earth. A downloadable file with the volcanoes organized regionally is also available directly from the GVP website (www.volcano.si.edu) and provides the most current volcano data set. Limitations of the implied accuracy of spacially plotted data at high zoom levels are also apparent using platforms such as Google Earth. Real and apparent mismatches between plotted locations and the summits of some volcanoes seen in Google Earth satellite imagery occur for reasons including data precision (deg/min vs. deg/min/sec) and the GVP convention of plotting the center-point of large volcanic fields, which often do not correspond to specific volcanic vents. A more fundamental problem originates from the fact that regional topographic mapping does not utilize a standardized global datum, so that locations from topographic maps often diverge from those of the World Geodetic System datum used in geo-registered satellite imagery. These limitations notwithstanding, virtual globe platforms such as Google Earth provide an easily accessible pathway to volcano data for a broad spectrum of users ranging from the home/classroom to Earth scientists.

  18. Santorini Volcano

    USGS Publications Warehouse

    Druitt, T.H.; Edwards, L.; Mellors, R.M.; Pyle, D.M.; Sparks, R.S.J.; Lanphere, M.; Davies, M.; Barreirio, B.

    1999-01-01

    Santorini is one of the most spectacular caldera volcanoes in the world. It has been the focus of significant scientific and scholastic interest because of the great Bronze Age explosive eruption that buried the Minoan town of Akrotiri. Santorini is still active. It has been dormant since 1950, but there have been several substantial historic eruptions. Because of this potential risk to life, both for the indigenous population and for the large number of tourists who visit it, Santorini has been designated one of five European Laboratory Volcanoes by the European Commission. Santorini has long fascinated geologists, with some important early work on volcanoes being conducted there. Since 1980, research groups at Cambridge University, and later at the University of Bristol and Blaise Pascal University in Clermont-Ferrand, have collected a large amount of data on the stratigraphy, geochemistry, geochronology and petrology of the volcanics. The volcanic field has been remapped at a scale of 1:10 000. A remarkable picture of cyclic volcanic activity and magmatic evolution has emerged from this work. Much of this work has remained unpublished until now. This Memoir synthesizes for the first time all the data from the Cambridge/Bristol/Clermont groups, and integrates published data from other research groups. It provides the latest interpretation of the tectonic and magmatic evolution of Santorini. It is accompanied by the new 1:10 000 full-colour geological map of the island.

  19. Taosi Observatory

    NASA Astrophysics Data System (ADS)

    Sun, Xiaochun

    Taosi observatory is the remains of a structure discovered at the later Neolithic Taosi site located in Xiangfen County, Shanxi Province, in north-central China. The structure is a walled enclosure on a raised platform. Only rammed-earth foundations of the structure remained. Archaeoastronomical studies suggest that this structure functioned as an astronomical observatory. Historical circumstantial evidence suggests that it was probably related to the legendary kingdom of Yao from the twenty-first century BC.

  20. Vatican Observatory

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Vatican Observatory is one of the oldest astronomical institutes in the world. It began with the reformation of the calendar in 1582. At the Roman College, Father Angelo Secchi first classified stars according to their spectra. With these rich traditions Leo XIII, in 1891, formally founded the Vatican Observatory on a hillside behind the dome of St Peter's Basilica. In 1935 Pius XI provided a...

  1. A scale for ranking volcanoes by risk

    NASA Astrophysics Data System (ADS)

    Scandone, Roberto; Bartolini, Stefania; Martí, Joan

    2016-01-01

    We propose a simple volcanic risk coefficient (VRC) useful for comparing the degree of risk arising from different volcanoes, which may be used by civil protection agencies and volcano observatories to rapidly allocate limited resources even without a detailed knowledge of each volcano. Volcanic risk coefficient is given by the sum of the volcanic explosivity index (VEI) of the maximum expected eruption from the volcano, the logarithm of the eruption rate, and the logarithm of the population that may be affected by the maximum expected eruption. We show how to apply the method to rank the risk using as examples the volcanoes of Italy and in the Canary Islands. Moreover, we demonstrate that the maximum theoretical volcanic risk coefficient is 17 and pertains to the large caldera-forming volcanoes like Toba or Yellowstone that may affect the life of the entire planet. We develop also a simple plugin for a dedicated Quantum Geographic Information System (QGIS) software to graphically display the VRC of different volcanoes in a region.

  2. A compilation of sulfur dioxide and carbon dioxide emission-rate data from Cook Inlet volcanoes (Redoubt, Spurr, Iliamna, and Augustine), Alaska during the period from 1990 to 1994

    USGS Publications Warehouse

    Doukas, Michael P.

    1995-01-01

    Airborne sulfur dioxide (SO2) gas sampling of the Cook Inlet volcanoes (Mt. Spurr, Redoubt, Iliamna, and Augustine) began in 1986 when several measurements were carried out at Augustine volcano during the eruption of 1986 (Rose and others, 1988). More systematic monitoring for SO2 began in March 1990 and for carbon dioxide (CO2) began in June, 1990 at Redoubt Volcano (Brantley, 1990 and Casadevall and others, 1994) and continues to the present. This report contains all of the available daily SO2 and CO2 emission rates determined by the U.S. Geological Survey (USGS) from March 1990 through July 1994. Intermittent measurements (four to six month intervals) at Augustine and Iliamna began in 1990 and continues to the present. Intermittent measurements began at Mt. Spurr volcano in 1991, and were continued at more regular intervals from June, 1992 through the 1992 eruption at the Crater Peak vent to the present.

  3. Observations of Deep Long-Period (DLP) Seismic Events Beneath Aleutian Arc Volcanoes; 1989 to 2002

    NASA Astrophysics Data System (ADS)

    Power, J. A.; Stihler, S. D.; White, R. A.; Moran, S. C.

    2002-12-01

    Between October 1989 and September 2002 the Alaska Volcano Observatory (AVO) located 149 Deep Long-Period events (DLP) at nine volcanic centers in the Aleutian arc. Many more were detected but could not be located reliably. These events occur at mid- to lower- crustal depths (10 to 50 km) and are characterized by emergent phases, extended codas, and a strong spectral peak generally between 2 and 4 Hz. Observed wave velocities and particle motions indicate that the dominant phases are P- and S-waves. The average reduced displacement of Aleutian DLPs is 28 cm2 and the largest event has a reduced displacement of 589 cm2 (or ML 2.5). DLP epicenters often extend over broad areas (5 to 30 km) that surround active volcanoes. DLP events are often highly clustered in time, with several occurring over a period of 3 to 30 minutes. Within these clusters individual DLPs are often separated by lower amplitude volcanic tremor with a similar spectral character. Higher frequency signals and/or volcano-tectonic earthquakes at similar depths are occasionally associated with DLP clusters. DLPs have now been identified at a number of volcanoes including Mammoth Mountain in 1989 and Mount Pinatubo in 1991, where they have been linked to the movement of basaltic magma. At most Aleutian volcanoes DLPs appear to occur as part of background seismicity. A likely explanation is that they reflect a relatively steady-state process of ascent of mafic magma over broad areas in lower and middle portions of the crust. At Mount Spurr DLP seismicity was initiated by the 1992 eruptions and then slowly declined until 1997, suggesting these events reflect changes in magma flux caused by the depressurization of the magmatic system during the eruptions. At Shishaldin Volcano small, short-lived increases in DLP seismicity occurred about nine months prior to the 19 April 1999 eruption and again roughly five weeks after the eruption, suggesting a link between eruptive activity and magma flux in the mid- to lower-crust. The occurrence of DLPS prior to eruptions at Pinatubo and Shishladin suggests that these events may provide some of the earliest indication of renewed volcanic unrest.

  4. WOVOdat Progress 2012: Installable DB template for Volcano Monitoring Database

    NASA Astrophysics Data System (ADS)

    Ratdomopurbo, A.; Widiwijayanti, C.; Win, N.-T.-Z.; Chen, L.-D.; Newhall, C.

    2012-04-01

    WOVOdat is the World Organization of Volcano Observatories' (WOVO) Database of Volcanic Unrest. Volcanoes are frequently restless but only a fraction of unrest leads to eruptions. We aim to compile and make the data of historical volcanic unrest available as a reference tool during volcanic crises, for observatory or other user to compare or look for systematic in many unrest episodes, and also provide educational tools for teachers and students on understanding volcanic processes. Furthermore, we promote the use of relational databases for countries that are still planning to develop their own monitoring database. We are now in the process of populating WOVOdat in collaboration with volcano observatories worldwide. Proprietary data remains at the observatories where the data originally from. Therefore, users who wish to use the data for publication or to obtain detail information about the data should directly contact the observatories. To encourage the use of relational database system in volcano observatories with no monitoring database, WOVOdat project is preparing an installable standalone package. This package is freely downloadable through our website (www.wovodat.org), ready to install and serve as database system in the local domain to host various types of volcano monitoring data. The WOVOdat project is now hosted at Earth Observatory of Singapore (Nanyang Technological University). In the current stage of data population, our website supports interaction between WOVOdat developers, observatories, and other partners in building the database, e.g. accessing schematic design, information and documentation, and also data submission. As anticipation of various data formats coming from different observatories, we provide an interactive tools for user to convert their data into standard WOVOdat format file before then able to upload and store in the database system. We are also developing various visualization tools that will be integrated in the system to ease user on querying and viewing the data. As soon as the database is sufficiently populated, data and tools will made accessible to public users.

  5. Nyiragonga Volcano

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of the Nyiragonga volcano eruption in the Congo was acquired on January 28, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters about 50 to 300 feet ), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    Image: A river of molten rock poured from the Nyiragongo volcano in the Congo on January 18, 2002, a day after it erupted, killing dozens, swallowing buildings and forcing hundreds of thousands to flee the town of Goma. The flow continued into Lake Kivu. The lave flows are depicted in red on the image indicating they are still hot. Two of them flowed south form the volcano's summit and went through the town of Goma. Another flow can be seen at the top of the image, flowing towards the northwest. One of Africa's most notable volcanoes, Nyiragongo contained an active lava lake in its deep summit crater that drained catastrophically through its outer flanks in 1977. Extremely fluid, fast-moving lava flows draining from the summit lava lake in 1977 killed 50 to 100 people, and several villages were destroyed. The image covers an area of 21 x 24 km and combines a thermal band in red, and two infrared bands in green and blue.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

  6. Keele Observatory

    NASA Astrophysics Data System (ADS)

    Theodorus van Loon, Jacco; Albinson, James; Bagnall, Alan; Bryant, Lian; Caisley, Dave; Doody, Stephen; Johnson, Ian; Klimczak, Paul; Maddison, Ron; Robinson, StJohn; Stretch, Matthew; Webb, John

    2015-08-01

    Keele Observatory was founded by Dr. Ron Maddison in 1962, on the hill-top campus of Keele University in central England, hosting the 1876 Grubb 31cm refractor from Oxford Observatory. It since acquired a 61cm research reflector, a 15cm Halpha solar telescope and a range of other telescopes. Run by a group of volunteering engineers and students under directorship of a Keele astrophysicist, it is used for public outreach as well as research. About 4,000 people visit the observatory every year, including a large number of children. We present the facility, its history - including involvement in the 1919 Eddington solar eclipse expedition which proved Albert Einstein's theory of general relativity - and its ambitions to erect a radio telescope on its site.

  7. Iridium emissions from Hawaiian volcanoes

    NASA Technical Reports Server (NTRS)

    Finnegan, D. L.; Zoller, W. H.; Miller, T. M.

    1988-01-01

    Particle and gas samples were collected at Mauna Loa volcano during and after its eruption in March and April, 1984 and at Kilauea volcano in 1983, 1984, and 1985 during various phases of its ongoing activity. In the last two Kilauea sampling missions, samples were collected during eruptive activity. The samples were collected using a filterpack system consisting of a Teflon particle filter followed by a series of 4 base-treated Whatman filters. The samples were analyzed by INAA for over 40 elements. As previously reported in the literature, Ir was first detected on particle filters at the Mauna Loa Observatory and later from non-erupting high temperature vents at Kilauea. Since that time Ir was found in samples collected at Kilauea and Mauna Loa during fountaining activity as well as after eruptive activity. Enrichment factors for Ir in the volcanic fumes range from 10,000 to 100,000 relative to BHVO. Charcoal impregnated filters following a particle filter were collected to see if a significant amount of the Ir was in the gas phase during sample collection. Iridium was found on charcoal filters collected close to the vent, no Ir was found on the charcoal filters. This indicates that all of the Ir is in particulate form very soon after its release. Ratios of Ir to F and Cl were calculated for the samples from Mauna Loa and Kilauea collected during fountaining activity. The implications for the KT Ir anomaly are still unclear though as Ir was not found at volcanoes other than those at Hawaii. Further investigations are needed at other volcanoes to ascertain if basaltic volcanoes other than hot spots have Ir enrichments in their fumes.

  8. Establishment, test and evaluation of a prototype volcano surveillance system

    NASA Technical Reports Server (NTRS)

    Ward, P. L.; Eaton, J. P.; Endo, E.; Harlow, D.; Marquez, D.; Allen, R.

    1973-01-01

    A volcano-surveillance system utilizing 23 multilevel earthquake counters and 6 biaxial borehole tiltmeters is being installed and tested on 15 volcanoes in 4 States and 4 foreign countries. The purpose of this system is to give early warning when apparently dormant volcanoes are becoming active. The data are relayed through the ERTS-Data Collection System to Menlo Park for analysis. Installation was completed in 1972 on the volcanoes St. Augustine and Iliamna in Alaska, Kilauea in Hawaii, Baker, Rainier and St. Helens in Washington, Lassen in California, and at a site near Reykjavik, Iceland. Installation continues and should be completed in April 1973 on the volcanoes Santiaguito, Fuego, Agua and Pacaya in Guatemala, Izalco in El Salvador and San Cristobal, Telica and Cerro Negro in Nicaragua.

  9. GeoFORCE Alaska, A Successful Summer Exploring Alaska's Geology

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2012-12-01

    Thirty years old this summer, RAHI, the Rural Alaska Honors Institute is a statewide, six-week, summer college-preparatory bridge program at the University of Alaska Fairbanks for Alaska Native and rural high school juniors and seniors. This summer, in collaboration with the University of Texas Austin, the Rural Alaska Honors Institute launched a new program, GeoFORCE Alaska. This outreach initiative is designed to increase the number and diversity of students pursuing STEM degree programs and entering the future high-tech workforce. It uses Earth science to entice kids to get excited about dinosaurs, volcanoes and earthquakes, and includes physics, chemistry, math, biology and other sciences. Students were recruited from the Alaska's Arctic North Slope schools, in 8th grade to begin the annual program of approximately 8 days, the summer before their 9th grade year and then remain in the program for all four years of high school. They must maintain a B or better grade average and participate in all GeoFORCE events. The culmination is an exciting field event each summer. Over the four-year period, events will include trips to Fairbanks and Anchorage, Arizona, Oregon and the Appalachians. All trips focus on Earth science and include a 100+ page guidebook, with tests every night culminating with a final exam. GeoFORCE Alaska was begun by the University of Alaska Fairbanks in partnership with the University of Texas at Austin, which has had tremendous success with GeoFORCE Texas. GeoFORCE Alaska is managed by UAF's long-standing Rural Alaska Honors Institute, that has been successfully providing intense STEM educational opportunities for Alaskan high school students for over 30 years. The program will add a new cohort of 9th graders each year for the next four years. By the summer of 2015, GeoFORCE Alaska is targeting a capacity of 160 students in grades 9th through 12th. Join us to find out more about this exciting new initiative, which is enticing young Alaska Native and minority students into the geosciences. View them as they explore the permafrost tunnel in Fairbanks, sand dunes in Anchorage, Portage Glacier, Matanuska-Susitna Glacier, and the Trans-Alaska pipeline damage from the earthquake of 2002.

  10. Santorini Volcano

    NASA Astrophysics Data System (ADS)

    Heiken, Grant

    What is it about Santorini (Thera) that attracts volcanologists? This small archipelago in the Aegean has captivated volcanic pilgrims since Fouque published his geologic study of the volcanic field in 1879 [Fouqué, 1879].It must be the combination of its spectacular setting, rising out of the blue waters of the Aegean, the remarkable exposures that lay open its violent past for everyone to see, or possibly the slower pace of life and remarkable Greek hospitality Perhaps it is the Lower Bronze Age town of Akrotiri, destroyed yet preserved by a large explosive eruption 3600 years ago. There are thousands of volcanoes yet to be studied on our planet, but for 140 years, groups of volcanologists have regularly visited this flooded caldera complex to add yet another bit of information to the foundation laid by Fouqué.

  11. One hundred years of volcano monitoring in Hawaii

    USGS Publications Warehouse

    Kauahikaua, Jim; Poland, Mike

    2012-01-01

    In 2012 the Hawaiian Volcano Observatory (HVO), the oldest of five volcano observatories in the United States, is commemorating the 100th anniversary of its founding. HVO's location, on the rim of Kilauea volcano (Figure 1)—one of the most active volcanoes on Earth—has provided an unprecedented opportunity over the past century to study processes associated with active volcanism and develop methods for hazards assessment and mitigation. The scientifically and societally important results that have come from 100 years of HVO's existence are the realization of one man's vision of the best way to protect humanity from natural disasters. That vision was a response to an unusually destructive decade that began the twentieth century, a decade that saw almost 200,000 people killed by the effects of earthquakes and volcanic eruptions.

  12. One hundred years of volcano monitoring in Hawaii

    USGS Publications Warehouse

    Kauahikaua, J.; Poland, M.

    2012-01-01

    In 2012 the Hawaiian Volcano Observatory (HVO), the oldest of five volcano observatories in the United States, is commemorating the 100th anniversary of its founding. HVO's location, on the rim of Klauea volcano (Figure 1)one of the most active volcanoes on Earthhas provided an unprecedented opportunity over the past century to study processes associated with active volcanism and develop methods for hazards assessment and mitigation. The scientifically and societally important results that have come from 100 years of HVO's existence are the realization of one man's vision of the best way to protect humanity from natural disasters. That vision was a response to an unusually destructive decade that began the twentieth century, a decade that saw almost 200,000 people killed by the effects of earthquakes and volcanic eruptions.

  13. Lightning and electrical activity during the 2009 eruptions of Redoubt Volcano

    NASA Astrophysics Data System (ADS)

    Thomas, R. J.; Behnke, S. A.; Krehbiel, P. R.; Rison, W.; Edens, H. E.; McNutt, S. R.; Higman, B.; Holzworth, R. H.; Thomas, J. N.

    2009-12-01

    The warning of the impending eruption of Redoubt by the Alaska Volcano Observatory enabled us to set up a 4-station VHF Lightning Mapping Array (LMA) along the Kenai coast in time to capture the complete sequence of eruptions. The network was situated along a 60 km long north-south line, 70-80 km east of Redoubt on the opposite side of Cook Inlet, and accurately measured the arrival times of VHF radiation produced by electrical discharges during the eruptions. Spectacular and often extremely vigorous electrical activity and lightning occurred during most of explosive events between 23 March and 4 April 2009. The mapping network produced detailed plan-position images of the sequence of discharges over and downwind of the volcano during each eruption. The lightning activity was essentially continuous and uncountable during the explosive phase of each eruption, gradually becoming more discrete and larger as the activity occurred in the plume. During most of the eruptions the lightning remained within 10 km relatively close to the volcano, but during the major eruptions of 23:30 UTC 28 March and the final eruption of 14:00 UTC 4 April the lightning-producing plume drifted across Cook Inlet over the populated Kenai peninsula coast. Individual ground strikes and possibly some in-cloud lightning events were also located by two low-frequency sferics location systems. The BLM network used for forest fire information detected 518 strikes over the full course of the eruptions. The more widespread World Wide Lightning Location Network (WWLLN) located 486 strikes using lower frequency radio waves. Most of the eruptions occurred during overcast or stormy weather and could not be seen visually, but during 3 eruptions the weather was clear enough for the lightning to be visually observed and also captured on photos and video. The visual observations were reported to be spectacular. We are working to correlate the lightning in the photos with the LMA and other detections.

  14. Advances in volcano monitoring and risk reduction in Latin America

    NASA Astrophysics Data System (ADS)

    McCausland, W. A.; White, R. A.; Lockhart, A. B.; Marso, J. N.; Assitance Program, V. D.; Volcano Observatories, L. A.

    2014-12-01

    We describe results of cooperative work that advanced volcanic monitoring and risk reduction. The USGS-USAID Volcano Disaster Assistance Program (VDAP) was initiated in 1986 after disastrous lahars during the 1985 eruption of Nevado del Ruiz dramatizedthe need to advance international capabilities in volcanic monitoring, eruption forecasting and hazard communication. For the past 28 years, VDAP has worked with our partners to improve observatories, strengthen monitoring networks, and train observatory personnel. We highlight a few of the many accomplishments by Latin American volcano observatories. Advances in monitoring, assessment and communication, and lessons learned from the lahars of the 1985 Nevado del Ruiz eruption and the 1994 Paez earthquake enabled the Servicio Geológico Colombiano to issue timely, life-saving warnings for 3 large syn-eruptive lahars at Nevado del Huila in 2007 and 2008. In Chile, the 2008 eruption of Chaitén prompted SERNAGEOMIN to complete a national volcanic vulnerability assessment that led to a major increase in volcano monitoring. Throughout Latin America improved seismic networks now telemeter data to observatories where the decades-long background rates and types of seismicity have been characterized at over 50 volcanoes. Standardization of the Earthworm data acquisition system has enabled data sharing across international boundaries, of paramount importance during both regional tectonic earthquakes and during volcanic crises when vulnerabilities cross international borders. Sharing of seismic forecasting methods led to the formation of the international organization of Latin American Volcano Seismologists (LAVAS). LAVAS courses and other VDAP training sessions have led to international sharing of methods to forecast eruptions through recognition of precursors and to reduce vulnerabilities from all volcano hazards (flows, falls, surges, gas) through hazard assessment, mapping and modeling. Satellite remote sensing data-sharing facilitatescross-border identification and warnings of ash plumes for aviation. Overall, long-term strategies of data collection and experience-sharing have helped Latin American observatories improve their monitoring and create informed communities cognizant of vulnerabilities inherent in living near volcanoes.

  15. Grand Observatory

    NASA Astrophysics Data System (ADS)

    Young, Eric W.

    2002-01-01

    Various concepts have been recently presented for a 100 m class astronomical observatory. The science virtues of such an observatory are many: resolving planets orbiting around other stars, resolving the surface features of other stars, extending our temporal reach back toward the beginning (at and before stellar and galactic development), improving on the Next Generation Space Telescope, and other (perhaps as yet) undiscovered purposes. This observatory would be a general facility instrument with wide spectral range from at least the near ultraviolet to the mid infrared. The concept espoused here is based on a practical, modular design located in a place where temperatures remain (and instruments could operate) within several degrees of absolute zero with no shielding or cooling. This location is the bottom of a crater located near the north or south pole of the moon, most probably the South Polar Depression. In such a location the telescope would never see the sun or the earth, hence the profound cold and absence of stray light. The ideal nature of this location is elaborated herein. It is envisioned that this observatory would be assembled and maintained remotely through the use of expert robotic systems. A base station would be located above the crater rim with (at least occasional) direct line-of-sight access to the earth. Certainly it would be advantageous, but not absolutely essential, to have humans travel to the site to deal with unexpected contingencies. Further, observers and their teams could eventually travel there for extended observational campaigns. Educational activities, in general, could be furthered thru extended human presence. Even recreational visitors and long term habitation might follow.

  16. Home Observatories

    NASA Astrophysics Data System (ADS)

    Moore, P.; Murdin, P.

    2000-11-01

    Sooner or later—generally sooner, rather than later—the average amateur astronomer is going to feel the need for a telescope. Binoculars are of immense use (see BINOCULAR ASTRONOMY), but their low magnification means that they are bound to be limited. Most amateur societies either have observatories or include members with telescopes of their own (see AMATEUR ASTRONOMICAL SOCIETIES) but it is muc...

  17. Detecting small geothermal features at Northern Pacific volcanoes with ASTER thermal infrared data

    NASA Astrophysics Data System (ADS)

    Wessels, R.; Senyukov, S.; Tranbenkova, A.; Ramsey, M. S.; Schneider, D. J.

    2004-12-01

    The Alaska Volcano Observatory (AVO) and the Kamchatkan Volcanic Eruption Response Team (KVERT) monitor the eruptive state of volcanoes throughout the Aleutian, Kamchatkan, and Kurile arcs. This is accomplished in part by analyzing thermal infrared (TIR) data from the Advanced Very High Resolution Radiometer (AVHRR) and Moderate-resolution Imaging Spectroradiometer (MODIS) sensors at least twice per day for major thermal anomalies. The AVHRR and MODIS 1-km spatial resolution data have been very useful for detecting large and/or high-temperature thermal signatures such as Strombolian activity as well as lava and pyroclastic flows. Such anomalies commonly indicate a major eruptive event is in progress. However, in order to observe and quantify small and/or lower temperature thermal features such as fumaroles and lava domes, higher spatial resolution data with better radiometric and spectral resolution are required. We have reviewed 2600 available night and day time TIR scenes acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) over the volcanoes of the northern Pacific. The current archive spans from March, 2000 to present. ASTER is the only instrument that routinely acquires high spatial resolution (30 - 90 m) night time data over volcanic targets. These data sets typically contain 5 TIR (8-12 microns) with 90 meter spatial resolution and 6 shortwave infrared (SWIR) bands (1-3 microns) with 30 meter spatial resolution. After the general survey of the volcanic arcs, we have focused our efforts on several targets. Mt. Hague, in the Emmons Lake complex on the Alaska Peninsula, has had mostly cloud-free ASTER observations for twenty night time TIR and six daytime TIR since August 2000. A small lake in the lower crater of Mt. Hague has had a history of appearing and disappearing over the last few years. The ASTER data combined with several recent field observations allow us to track the changes in lake area and associated temperatures. With more frequent observations, we hope to determine the mechanism of these changes. The 1975-76 craters and lava flows of New Tolbachik Volcano in central Kamchatka appear as persistent thermal features in clear night time ASTER TIR data with ASTER TIR temperatures as high as 22° C. Handheld FLIR TIR images (~0.5m pixels) from August 2004 show temperatures >176° C on the lava flow and >226° C in the crater wall. Mutnovsky and Gorely Volcanoes in southern Kamchatka also have several persistent thermal features in the ASTER data from late 2001 until at least November 2003. These features correlate to a vigorous fumarole field and crater lakes. The Mutnovsky thermal features were also observed in AVHRR data by KEMSD in March, June, and July 2003. The goal of this work is to better detect changes in current volcano activity or precursors to new activity. Our ongoing survey of the ASTER TIR data has created a database of many small (<90 m) or low temperature (20 to 38° C) thermal features at several volcanoes in the northern Pacific region. We will attempt to observe each of the identified features at least annually using ASTER data as it becomes available over each target.

  18. Volcano hazards program in the United States

    USGS Publications Warehouse

    Tilling, R.I.; Bailey, R.A.

    1985-01-01

    Volcano monitoring and volcanic-hazards studies have received greatly increased attention in the United States in the past few years. Before 1980, the Volcanic Hazards Program was primarily focused on the active volcanoes of Kilauea and Mauna Loa, Hawaii, which have been monitored continuously since 1912 by the Hawaiian Volcano Observatory. After the reawakening and catastrophic eruption of Mount St. Helens in 1980, the program was substantially expanded as the government and general public became aware of the potential for eruptions and associated hazards within the conterminous United States. Integrated components of the expanded program include: volcanic-hazards assessment; volcano monitoring; fundamental research; and, in concert with federal, state, and local authorities, emergency-response planning. In 1980 the David A. Johnston Cascades Volcano Observatory was established in Vancouver, Washington, to systematically monitor the continuing activity of Mount St. Helens, and to acquire baseline data for monitoring the other, presently quiescent, but potentially dangerous Cascade volcanoes in the Pacific Northwest. Since June 1980, all of the eruptions of Mount St. Helens have been predicted successfully on the basis of seismic and geodetic monitoring. The largest volcanic eruptions, but the least probable statistically, that pose a threat to western conterminous United States are those from the large Pleistocene-Holocene volcanic systems, such as Long Valley caldera (California) and Yellowstone caldera (Wyoming), which are underlain by large magma chambers still potentially capable of producing catastrophic caldera-forming eruptions. In order to become better prepared for possible future hazards associated with such historically unpecedented events, detailed studies of these, and similar, large volcanic systems should be intensified to gain better insight into caldera-forming processes and to recognize, if possible, the precursors of caldera-forming eruptions. ?? 1985.

  19. First scientific contributions from the High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    León Vargas, H.; HAWC Collaboration

    2015-09-01

    The High Altitude Water Cherenkov Observatory (HAWC), located at the slopes of the volcanoes Sierra Negra and Pico de Orizaba in Mexico, was inaugurated on March 20, 2015. However, data taking started in August 2013 with a partially deployed observatory and since then the instrument has collected data as it got closer to its final configuration. HAWC is a ground based TeV gamma-ray observatory with a large field of view that will be used to study the Northern sky with high sensitivity. In this contribution we present some of the results obtained with the partially built instrument and the expected capabilities to detect different phenomena with the complete observatory.

  20. Ol Doinyo Lengai Volcano

    Scientists from the Volcano Disaster Assistance Program team and the Geological Survey of Tanzania take a sample of the most recent ashfall from Ol Doinyo Lengai as the volcano looms in the background....

  1. The EarthScope Plate Boundary Observatory Response to the 2006 Augustine Alaskan Volcanic Eruption

    NASA Astrophysics Data System (ADS)

    Pauk, B.; Feaux, K.; Jackson, M.; Friesen, B.; Enders, M.; Baldwin, A.; Fournier, K.; Marzulla, A.

    2006-12-01

    During September of 2006, UNAVCO installed five permanent Plate Boundary Observatory (PBO) GPS stations on Augustine Volcano, in the lower Cook Inlet of Alaska. The installations were done at the request of the PBO Magmatic Systems committee in response to the January 11, 2006 eruption of Augustine Volcano. Prior to the eruption, PBO installed five permanent GPS stations on Augustine in 2004. The five existing stations on the volcano were instrumental in detecting precursory deformation of the volcano's flanks prior to and during the eruption. During the course of the first explosive phase of the eruption, two existing PBO stations, AV03 and AV05 were subsequently destroyed by separate pyroclastic flows. The existing station AV04 was heavily damaged by a separate pyroclastic flow during the continuous phase of the eruption and was repaired during September as well. Existing stations AV01 and AV02 were not affected or damaged by the eruption and remained operating during the entire eruptive phase and subsequent debris flows. All five new stations, and maintenance on the three remaining existing stations, were completed by PBO field crews with helicopter support provided by Maritime Helicopters. Lack of roads and drivable trails on the remote volcanic island required that all equipment be transported to each site from an established base camp by slinging gear beneath the helicopter and internal loads. Each new and existing station installed on the volcano consists of a standard short braced GPS monument, two solar panels mounted to an inclined structure, and a six foot high Plaschem enclosure with two solar panels mounted to one of the inclined sides. Each Plaschem houses 24 12 volt batteries that power a Trimble NetRS GPS receiver and one or two Intuicom radios and are recharged by the solar panels. Data from each GPS receiver is telemetered directly or through a repeater radio to a base station located in the town of Homer that transmits the data over the internet to the UNAVCO data archive at ftp://data-out.unavco.or/pub/PBO_rinex where it is made freely available to the public.

  2. Bayfordbury Observatory

    NASA Astrophysics Data System (ADS)

    Jones, Hugh

    2015-08-01

    Bayfordbury observatory has formed an integral part of the University of Hertfordshire's astronomy-related degree programmes since it opened in 1970 and is used by students from the first week of their degree through to their final year, as well as by PhD students and staff. It has a wide range of atmospheric and astronomical equipment and in particular has five queue scheduled telescopes performing a range of different science programmes. Although the site is rather poor the synergy with atmospheric sensing equipment in particular a LIDAR enables robust quality control of the data.

  3. Ice Observatory

    NASA Astrophysics Data System (ADS)

    blugerman, n.

    2015-10-01

    My project is to make ice observatories to perceive astral movements as well as light phenomena in the shape of cosmic rays and heat, for example.I find the idea of creating an observation point in space, that in time will change shape and eventually disappear, in consonance with the way we humans have been approaching the exploration of the universe since we started doing it. The transformation in the elements we use to understand big and small transformations, within the universe elements.

  4. A Scientific Excursion: Volcanoes.

    ERIC Educational Resources Information Center

    Olds, Henry, Jr.

    1983-01-01

    Reviews an educationally valuable and reasonably well-designed simulation of volcanic activity in an imaginary land. VOLCANOES creates an excellent context for learning information about volcanoes and for developing skills and practicing methods needed to study behavior of volcanoes. (Author/JN)

  5. Alaska Permafrost

    General view of a 35-meter-high riverbank exposure of the ice-rich syngenetic permafrost (yedoma) containing large ice wedges along the Itkillik River in northern Alaska. Copyright-free photo courtesy of Mikhail Kanevskiy; University of Alaska Fairbanks, Institute of Northern Engineering....

  6. Volcano seismology

    USGS Publications Warehouse

    Chouet, B.

    2003-01-01

    A fundamental goal of volcano seismology is to understand active magmatic systems, to characterize the configuration of such systems, and to determine the extent and evolution of source regions of magmatic energy. Such understanding is critical to our assessment of eruptive behavior and its hazardous impacts. With the emergence of portable broadband seismic instrumentation, availability of digital networks with wide dynamic range, and development of new powerful analysis techniques, rapid progress is being made toward a synthesis of high-quality seismic data to develop a coherent model of eruption mechanics. Examples of recent advances are: (1) high-resolution tomography to image subsurface volcanic structures at scales of a few hundred meters; (2) use of small-aperture seismic antennas to map the spatio-temporal properties of long-period (LP) seismicity; (3) moment tensor inversions of very-long-period (VLP) data to derive the source geometry and mass-transport budget of magmatic fluids; (4) spectral analyses of LP events to determine the acoustic properties of magmatic and associated hydrothermal fluids; and (5) experimental modeling of the source dynamics of volcanic tremor. These promising advances provide new insights into the mechanical properties of volcanic fluids and subvolcanic mass-transport dynamics. As new seismic methods refine our understanding of seismic sources, and geochemical methods better constrain mass balance and magma behavior, we face new challenges in elucidating the physico-chemical processes that cause volcanic unrest and its seismic and gas-discharge manifestations. Much work remains to be done toward a synthesis of seismological, geochemical, and petrological observations into an integrated model of volcanic behavior. Future important goals must include: (1) interpreting the key types of magma movement, degassing and boiling events that produce characteristic seismic phenomena; (2) characterizing multiphase fluids in subvolcanic regimes and determining their physical and chemical properties; and (3) quantitatively understanding multiphase fluid flow behavior under dynamic volcanic conditions. To realize these goals, not only must we learn how to translate seismic observations into quantitative information about fluid dynamics, but we also must determine the underlying physics that governs vesiculation, fragmentation, and the collapse of bubble-rich suspensions to form separate melt and vapor. Refined understanding of such processes-essential for quantitative short-term eruption forecasts-will require multidisciplinary research involving detailed field measurements, laboratory experiments, and numerical modeling.

  7. Synergistic Use of Satellite Volcano Detection and Science: A Fifteen Year Perspective of ASTER on Terra

    NASA Astrophysics Data System (ADS)

    Ramsey, M. S.

    2014-12-01

    The success of Terra-based observations using the ASTER instrument of active volcanic processes early in the mission gave rise to a funded NASA program designed to both increase the number of ASTER observations following an eruption and validate the satellite data. The urgent request protocol (URP) system for ASTER grew out of this initial study and has now operated in conjunction with and the support of the Alaska Volcano Observatory, the University of Alaska Fairbanks, the University of Hawaii, the USGS Land Processes DAAC, and the ASTER science team. The University of Pittsburgh oversees this rapid response/sensor-web system, which until 2011 had focused solely on the active volcanoes in the North Pacific region. Since that time, it has been expanded to operate globally with AVHRR and MODIS and now ASTER VNIR/TIR data are being acquired at numerous erupting volcanoes around the world. This program relies on the increased temporal resolution of AVHRR/MODIS midwave infrared data to trigger the next available ASTER observation, which results in ASTER data as frequently as every 2-5 days. For many targets, the URP has increased the observational frequency over active eruptions by as much 50%. The data have been used for operational response to new eruptions, longer-term scientific studies such as capturing detailed changes in lava domes/flows, pyroclastic flows and lahars. These data have also been used to infer the emplacement of new lava lobes, detect endogenous dome growth, and interpret hazardous dome collapse events. The emitted TIR radiance from lava surfaces has also been used effectively to model composition, texture and degassing. Now, this long-term archive of volcanic image data is being mined to provide statistics on the expectations of future high-repeat TIR data such as that proposed for the NASA HyspIRI mission. In summary, this operational/scientific program utilizing the unique properties of ASTER and the Terra mission has shown the potential for providing innovative and integrated synoptic measurements of geothermal activity, volcanic eruptions and their subsequent hazards globally.

  8. Streamlining volcano-related, web-based data display and design with a new U.S. Geological Survey Volcano Science Center website

    NASA Astrophysics Data System (ADS)

    Stovall, W. K.; Randall, M. J.; Cervelli, P. F.

    2011-12-01

    The goal of the newly designed U.S. Geological Survey (USGS) Volcano Science Center website is to provide a reliable, easy to understand, and accessible format to display volcano monitoring data and scientific information on US volcanoes and their hazards. There are greater than 150 active or potentially active volcanoes in the United States, and the Volcano Science Center aims to advance the scientific understanding of volcanic processes at these volcanoes and to lessen the harmful impacts of potential volcanic activity. To fulfill a Congressional mandate, the USGS Volcano Hazards Program must communicate scientific findings to authorities and the public in a timely and understandable form. The easiest and most efficient way to deliver this information is via the Internet. We implemented a new database model to organize website content, ensuring consistency, accuracy, and timeliness of information display. Real-time monitoring data is available for over 50 volcanoes in the United States, and web-site visitors are able to interact with a dynamic, map-based display system to access and analyze these data, which are managed by scientists from the five USGS volcano observatories. Helicorders, recent hypocenters, webcams, tilt measurements, deformation, gas emissions, and changes in hydrology can be viewed for any of the real-time instruments. The newly designed Volcano Science Center web presence streamlines the display of research findings, hazard assessments, and real-time monitoring data for the U.S. volcanoes.

  9. MATLAB tools for improved characterization and quantification of volcanic incandescence in Webcam imagery; applications at Kilauea Volcano, Hawai'i

    USGS Publications Warehouse

    Patrick, Matthew R.; Kauahikaua, James P.; Antolik, Loren

    2010-01-01

    Webcams are now standard tools for volcano monitoring and are used at observatories in Alaska, the Cascades, Kamchatka, Hawai'i, Italy, and Japan, among other locations. Webcam images allow invaluable documentation of activity and provide a powerful comparative tool for interpreting other monitoring datastreams, such as seismicity and deformation. Automated image processing can improve the time efficiency and rigor of Webcam image interpretation, and potentially extract more information on eruptive activity. For instance, Lovick and others (2008) provided a suite of processing tools that performed such tasks as noise reduction, eliminating uninteresting images from an image collection, and detecting incandescence, with an application to dome activity at Mount St. Helens during 2007. In this paper, we present two very simple automated approaches for improved characterization and quantification of volcanic incandescence in Webcam images at Kilauea Volcano, Hawai`i. The techniques are implemented in MATLAB (version 2009b, Copyright: The Mathworks, Inc.) to take advantage of the ease of matrix operations. Incandescence is a useful indictor of the location and extent of active lava flows and also a potentially powerful proxy for activity levels at open vents. We apply our techniques to a period covering both summit and east rift zone activity at Kilauea during 2008?2009 and compare the results to complementary datasets (seismicity, tilt) to demonstrate their integrative potential. A great strength of this study is the demonstrated success of these tools in an operational setting at the Hawaiian Volcano Observatory (HVO) over the course of more than a year. Although applied only to Webcam images here, the techniques could be applied to any type of sequential images, such as time-lapse photography. We expect that these tools are applicable to many other volcano monitoring scenarios, and the two MATLAB scripts, as they are implemented at HVO, are included in the appendixes. These scripts would require minor to moderate modifications for use elsewhere, primarily to customize directory navigation. If the user has some familiarity with MATLAB, or programming in general, these modifications should be easy. Although we originally anticipated needing the Image Processing Toolbox, the scripts in the appendixes do not require it. Thus, only the base installation of MATLAB is needed. Because fairly basic MATLAB functions are used, we expect that the script can be run successfully by versions earlier than 2009b.

  10. Publications of the Volcano Hazards Program 2005

    USGS Publications Warehouse

    Nathenson, Manuel

    2007-01-01

    The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic Hazards Assessments subactivity as funded by Congressional appropriation. Investigations are carried out in the Geology and Hydrology Disciplines of the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute, University of Hawaii Hilo, University of Utah, and University of Washington Geophysics Program. This report lists publications from all these institutions. This report contains only published papers and maps; numerous abstracts produced for presentations at scientific meetings have not been included. Publications are included based on date of publication with no attempt to assign them to Fiscal Year.

  11. Publications of the Volcano Hazards Program 2008

    USGS Publications Warehouse

    Nathenson, Manuel

    2010-01-01

    The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic Hazards Assessments subactivity as funded by Congressional appropriation. Investigations are carried out in the Geology and Hydrology Disciplines of the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute, University of Hawaii Manoa and Hilo, University of Utah, and University of Washington Geophysics Program. This report lists publications from all these institutions. This report contains only published papers and maps; numerous abstracts produced for presentations at scientific meetings have not been included. Publications are included based on date of publication with no attempt to assign them to Fiscal Year.

  12. Publications of the Volcano Hazards Program 2004

    USGS Publications Warehouse

    Nathenson, Manuel

    2006-01-01

    The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic Hazards Assessments subactivity as funded by Congressional appropriation. Investigations are carried out in the Geology and Hydrology Disciplines of the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute, University of Hawaii Hilo, University of Utah, and University of Washington Geophysics Program. This report lists publications from all these institutions. This bibliographic report contains only published papers and maps; numerous abstracts produced for presentations at scientific meetings have not been included. Publications are included based on date of publication with no attempt to assign them to Fiscal Year.

  13. Global Volcano Model

    NASA Astrophysics Data System (ADS)

    Sparks, R. S. J.; Loughlin, S. C.; Cottrell, E.; Valentine, G.; Newhall, C.; Jolly, G.; Papale, P.; Takarada, S.; Crosweller, S.; Nayembil, M.; Arora, B.; Lowndes, J.; Connor, C.; Eichelberger, J.; Nadim, F.; Smolka, A.; Michel, G.; Muir-Wood, R.; Horwell, C.

    2012-04-01

    Over 600 million people live close enough to active volcanoes to be affected when they erupt. Volcanic eruptions cause loss of life, significant economic losses and severe disruption to people's lives, as highlighted by the recent eruption of Mount Merapi in Indonesia. The eruption of Eyjafjallajökull, Iceland in 2010 illustrated the potential of even small eruptions to have major impact on the modern world through disruption of complex critical infrastructure and business. The effects in the developing world on economic growth and development can be severe. There is evidence that large eruptions can cause a change in the earth's climate for several years afterwards. Aside from meteor impact and possibly an extreme solar event, very large magnitude explosive volcanic eruptions may be the only natural hazard that could cause a global catastrophe. GVM is a growing international collaboration that aims to create a sustainable, accessible information platform on volcanic hazard and risk. We are designing and developing an integrated database system of volcanic hazards, vulnerability and exposure with internationally agreed metadata standards. GVM will establish methodologies for analysis of the data (eg vulnerability indices) to inform risk assessment, develop complementary hazards models and create relevant hazards and risk assessment tools. GVM will develop the capability to anticipate future volcanism and its consequences. NERC is funding the start-up of this initiative for three years from November 2011. GVM builds directly on the VOGRIPA project started as part of the GRIP (Global Risk Identification Programme) in 2004 under the auspices of the World Bank and UN. Major international initiatives and partners such as the Smithsonian Institution - Global Volcanism Program, State University of New York at Buffalo - VHub, Earth Observatory of Singapore - WOVOdat and many others underpin GVM.

  14. Alaska GeoFORCE, A New Geologic Adventure in Alaska

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2011-12-01

    RAHI, the Rural Alaska Honors Institute is a statewide, six-week, summer college-preparatory bridge program at the University of Alaska Fairbanks for Alaska Native and rural high school juniors and seniors. A program of rigorous academic activity combines with social, cultural, and recreational activities. Students are purposely stretched beyond their comfort levels academically and socially to prepare for the big step from home or village to a large culturally western urban campus. This summer RAHI is launching a new program, GeoFORCE Alaska. This outreach initiative is designed to increase the number and diversity of students pursuing STEM degree programs and entering the future high-tech workforce. It uses Earth science as the hook because most kids get excited about dinosaurs, volcanoes and earthquakes, but it includes physics, chemistry, math, biology and other sciences. Students will be recruited, initially from the Arctic North Slope schools, in the 8th grade to begin the annual program of approximately 8 days, the summer before their 9th grade year and then remain in the program for all four years of high school. They must maintain a B or better grade average and participate in all GeoFORCE events. The carrot on the end of the stick is an exciting field event each summer. Over the four-year period, events will include trips to Fairbanks, Arizona, Oregon and the Appalachians. All trips are focused on Earth science and include a 100+ page guidebook, with tests every night culminating with a final exam. GeoFORCE Alaska is being launched by UAF in partnership with the University of Texas at Austin, which has had tremendous success with GeoFORCE Texas. GeoFORCE Alaska will be managed by UAF's long-standing Rural Alaska Honors Insitute (RAHI) that has been successfully providing intense STEM educational opportunities for Alaskan high school students for almost 30 years. The Texas program, with adjustments for differences in culture and environment, will be replicated in Alaska, with plans to begin with 40 rising 9th graders during the summer of 2012. The program will continue to add a new cohort of 9th graders each year for the next four years. By the summer of 2015, GeoFORCE Alaska is targeting a capacty of 160 students in grades 9th through 12th.

  15. Frequency based satellite monitoring of small scale explosive activity at remote North Pacific volcanoes

    NASA Astrophysics Data System (ADS)

    Worden, Anna; Dehn, Jonathan; Webley, Peter

    2014-10-01

    Monitoring of volcanoes in the North Pacific can be an expensive and sometimes dangerous task, specifically for those located in Alaska (USA) and Kamchatka (Russia). An active frequency detection method previously used at Stromboli, Italy, uses the thermal- and mid-infrared wavelength bands from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data to detect anomalies at a volcano. This method focuses on small scale explosive activity, often referred to as Strombolian activity which can produce small spatter fields near a volcano's active vent. In the North Pacific, there are a number of volcanoes which exhibit small scale explosive activity and three are the focus of this study: Chuginadak (Mt. Cleveland) and Shishaldin in Alaska, and Karymsky Volcano in Kamchatka. Satellite images from the Advanced Very High Resolution Radiometer (AVHRR) were used to monitor the frequency of thermal features as well as the occurrence of ash plumes at each volcano. This data was then used to produce a time series spanning 2005-2010 for all three volcanoes. During this time period, each volcano underwent a series of eruptive cycles including background levels of activity, heightened frequency of small explosions (identified as precursory activity), and heightened activity typified by ash plume-producing eruptions. Each location has a unique precursory signal, both in timing and magnitude. The use of a previously developed method on a new sample set of volcanoes has proved the validity of this method as a monitoring tool for volcanoes with small scale explosive activity. This method should be applied to a larger set of volcanoes to continue the development and database production for its use as a volcano monitoring tool.

  16. Haystack Observatory

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Radio astronomy programs comprise three very-long-baseline interferometer projects, ten spectral line investigations, one continuum mapping in the 0.8 cm region, and one monitoring of variable sources. A low-noise mixer was used in mapping observations of 3C273 at 31 GHz and in detecting of a new methyl alcohol line at 36,169 MHz in Sgr B2. The new Mark 2 VLBI recording terminal was used in galactic H2O source observations using Haystack and the Crimean Observatory, USSR. One feature in W29 appears to have a diameter of 0.3 millisec of arc and a brightness temperature of 1.4 x 10 to the 15th power K. Geodetic baseline measurements via VLBI between Green Bank and Haystack are mutually consistent within a few meters. Radar investigations of Mercury, Venus, Mars, and the Moon have continued. The favorable opposition of Mars and improvements in the radar permit measurements on a number of topographic features with unprecedented accuracy, including scarps and crater walls. The floor of Mare Serenitatis slopes upward towards the northeast and is also the location of a strong gravitational anomaly.

  17. The Volcano Adventure Guide

    NASA Astrophysics Data System (ADS)

    Goff, Fraser

    2005-05-01

    Adventure travels to volcanoes offer chance encounters with danger, excitement, and romance, plus opportunities to experience scientific enlightenment and culture. To witness a violently erupting volcano and its resulting impacts on landscape, climate, and humanity is a powerful personal encounter with gigantic planetary forces. To study volcano processes and products during eruptions is to walk in the footsteps of Pliny himself. To tour the splendors and horrors of 25 preeminent volcanoes might be the experience of a lifetime, for scientists and nonscientists alike. In The Volcano Adventure Guide, we now have the ultimate tourist volume to lead us safely to many of the world's famous volcanoes and to ensure that we will see the important sites at each one.

  18. Volcanoes, Observations and Impact

    NASA Astrophysics Data System (ADS)

    Thurber, Clifford; Prejean, Stephanie

    Volcanoes are critical geologic hazards that challenge our ability to make long-term forecasts of their eruptive behaviors. They also have direct and indirect impacts on human lives and society. As is the case with many geologic phenomena, the time scales over which volcanoes evolve greatly exceed that of a human lifetime. On the other hand, the time scale over which a volcano can move from inactivity to eruption can be rather short: months, weeks, days, and even hours. Thus, scientific study and monitoring of volcanoes is essential to mitigate risk. There are thousands of volcanoes on Earth, and it is impractical to study and implement ground-based monitoring at them all. Fortunately, there are other effective means for volcano monitoring, including increasing capabilities for satellite-based technologies.

  19. Systematic re-analysis of volcano-seismic waveform data

    NASA Astrophysics Data System (ADS)

    Matoza, R. S.; Shearer, P. M.; Okubo, P.

    2013-12-01

    The analysis and interpretation of seismicity from mantle depths to the surface plays a key role in understanding how volcanoes work. We are developing and applying methods for the systematic reanalysis of waveforms from volcano-seismic networks, including high-precision earthquake relocation, spectral event classification, and stress drop estimates. Our primary dataset is the ~50-station permanent network of the USGS Hawaiian Volcano Observatory. We have produced a comprehensive multi-year catalog of high-precision relocated seismicity for all of Hawaii Island using waveform cross-correlation and cluster analysis. The 17 years of relocated seismicity exhibits a dramatic sharpening of earthquake clustering along faults, streaks, and magmatic features, permitting a more detailed understanding of fault geometries and volcanic and tectonic processes. We are currently developing techniques for the systematic classification and relocation of long-period seismicity at volcanoes. We are also performing comprehensive spectral analyses to estimate spatial variations in stress drop of shear-failure earthquakes.

  20. The Anatahan volcano-monitoring system

    NASA Astrophysics Data System (ADS)

    Marso, J. N.; Lockhart, A. B.; White, R. A.; Koyanagi, S. K.; Trusdell, F. A.; Camacho, J. T.; Chong, R.

    2003-12-01

    A real-time 24/7 Anatahan volcano-monitoring and eruption detection system is now operational. There had been no real-time seismic monitoring on Anatahan during the May 10, 2003 eruption because the single telemetered seismic station on Anatahan Island had failed. On May 25, staff from the Emergency Management Office (EMO) of the Commonwealth of the Northern Mariana Islands and the U. S. Geological Survey (USGS) established a replacement telemetered seismic station on Anatahan whose data were recorded on a drum recorder at the EMO on Saipan, 130 km to the south by June 5. In late June EMO and USGS staff installed a Glowworm seismic data acquisition system (Marso et al, 2003) at EMO and hardened the Anatahan telemetry links. The Glowworm system collects the telemetered seismic data from Anatahan and Saipan, places graphical display products on a webpage, and exports the seismic waveform data in real time to Glowworm systems at Hawaii Volcano Observatory and Cascades Volcano Observatory (CVO). In early July, a back-up telemetered seismic station was placed on Sarigan Island 40 km north of Anatahan, transmitting directly to the EMO on Saipan. Because there is currently no population on the island, at this time the principal hazard presented by Anatahan volcano would be air traffic disruption caused by possible erupted ash. The aircraft/ash hazard requires a monitoring program that focuses on eruption detection. The USGS currently provides 24/7 monitoring of Anatahan with a rotational seismic duty officer who carries a Pocket PC-cell phone combination that receives SMS text messages from the CVO Glowworm system when it detects large seismic signals. Upon receiving an SMS text message notification from the CVO Glowworm, the seismic duty officer can use the Pocket PC - cell phone to view a graphic of the seismic traces on the EMO Glowworm's webpage to determine if the seismic signal is eruption related. There have been no further eruptions since the monitoring system was installed, but regional tectonic earthquakes have provided frequent tests of the system. Reliance on a Pocket PC - cell phone requires that the seismic duty officer remain in an area with cell phone coverage. With this monitoring method, the USGS is able to provide rapid notice of an Anatahan eruption to the EMO and the Washington Volcano Ash Advisory Center. Reference Marso, J.N., Murray, T.L., Lockhart, A.B., Bryan, C.J., Glowworm: An extended PC-based Earthworm system for volcano monitoring. Abstracts, Cities On Volcanoes III, Hilo Hawaii, July 2003.

  1. Mud volcanoes on Mars?

    NASA Technical Reports Server (NTRS)

    Komar, Paul D.

    1991-01-01

    The term mud volcano is applied to a variety of landforms having in common a formation by extrusion of mud from beneath the ground. Although mud is the principal solid material that issues from a mud volcano, there are many examples where clasts up to boulder size are found, sometimes thrown high into the air during an eruption. Other characteristics of mud volcanoes (on Earth) are discussed. The possible presence of mud volcanoes, which are common and widespread on Earth, on Mars is considered.

  2. Water in Aleutian Arc Volcanoes

    NASA Astrophysics Data System (ADS)

    Plank, T.; Zimmer, M. M.; Hauri, E. H.

    2011-12-01

    In the past decade, baseline data have been obtained on pre-eruptive water contents for several volcanic arcs worldwide. One surprising observation is that parental magmas contain ~ 4 wt% H2O on average at each arc worldwide [1]. Within each arc, the variation from volcano to volcano is from 2 to 6 w% H2O, with few exceptions. The similar averages at different arcs are unexpected given the order of magnitude variations in the concentration of other slab tracers. H2O is clearly different from other tracers, however, being both a major driver of melting in the mantle and a major control of buoyancy and viscosity in the crust. Some process, such as mantle melting or crustal storage, apparently modulates the water content of mafic magmas at arcs. Mantle melting may deliver a fairly uniform product to the Moho, if the wet melt process includes a negative feedback. On the other hand, magmas with variable water content may be generated in the mantle, but a crustal filter may lead to magma degassing up to a common mid-to-upper crustal storage region. Testing between these two end-member scenarios is critical to our understanding of subduction dehydration, global water budgets, magmatic plumbing systems, melt generation and eruptive potential. The Alaska-Aleutian arc is a prime location to explore this fundamental problem in the subduction water cycle, because active volcanoes vary more than elsewhere in the world in parental H2O contents (based on least-degassed, mafic melt inclusions hosted primarily in olivine). For example, Shishaldin volcano taps magma with among the lowest H2O contents globally (~ 2 wt%) and records low pressure crystal fractionation [2], consistent with a shallow magma system (< 1 km bsl). At the other extreme, Augustine volcano is fed by a mafic parent that contains among the highest H2O globally (~ 7 wt%), and has evolved by deep crystal fractionation [2], consistent with a deep magma system (~ 14 km bsl). Do these magmas stall at different depths because of different crustal regimes or because of different primary magma compositions? Do magmas degas until they physically stall, or do they stall when they start to degas? One test of this is whether H2O contents correlate with tracers from the subduction zone that are not fractionated easily during crystal fractionation or degassing. We find a strong negative correlation between H2O/Ce (based on the maximum H2O measured in a given inclusion population) and Nb/Ce in eight Aleutian volcanoes, which is well explained by variable amounts of a slab fluid, but would be fortuitous, or strongly disturbed, if major degassing took place in the crust during magma ascent. Thus, geochemical data point to a strong slab-mantle control on H2O, that may set the future course of magma ascent, storage and eruption. Integrated studies are needed to test this prediction, including seismic imaging and geodetic response of the volcanic system, from the slab to the surface. [1] Plank, et al. (2011) Min. Mag. 75: 1648. [2] Zimmer, et al. (2010) J. Pet. 51: 2411-2444.

  3. The USGS Geomagnetism Program Observatory Network

    NASA Astrophysics Data System (ADS)

    Finn, C. A.

    2011-12-01

    The mission of the U.S. Geological Survey's Geomagnetism Program is to monitor the Earth's magnetic field. Using ground-based observatories, the Program provides continuous records of magnetic field variations covering long timescales, ranging from seconds to over a century. The Program disseminates magnetic data to various governmental, academic, and private institutions; it conducts research into the nature of geomagnetic variations for purposes of scientific understanding and hazard mitigation. The Program is an integral part of the U.S. Government's National Space Weather Program. In this presentation, we summarize recent operational accomplishments of the USGS Geomagnetism Program, including the addition of a real-time one-second data product, development of quasi-definitive data from selected observatories, and improvements to the magnetic observatory network in Alaska.

  4. Of Rings and Volcanoes

    NASA Astrophysics Data System (ADS)

    2002-01-01

    Fine Images of Saturn and Io with VLT NAOS-CONICA Summary With its new NAOS-CONICA Adaptive Optics facility, the ESO Very Large Telescope (VLT) at the Paranal Observatory has recently obtained impressive views of the giant planet Saturn and Io, the volcanic moon of Jupiter. They show the two objects with great clarity, unprecedented for a ground-based telescope. The photos were made during the ongoing commissioning of this major VLT instrument, while it is being optimized and prepared for regular observations that will start later this year. PR Photo 04a/02 : VLT NAOS-CONICA photo of the giant planet Saturn (composite H+K band image). PR Photo 04b/02 : The Jovian moon Io (Br-gamma image). PR Photo 04c/02 : The Jovian moon Io (composite Br-gamma + L' image). Commissioning of NAOS-CONICA progresses "First light" for the new NAOS-CONICA Adaptive Optics facility on the 8.2-m VLT YEPUN telescope at the Paranal Observatory was achieved in November 2001, cf. ESO PR 25/01. A second phase of the "commissioning" of the new facility began on January 22, 2002, now involving specialized observing modes and with the aim of trimming it to maximum performance before it is made available to the astronomers later this year. During this demanding and delicate work, more test images have been made of various astronomical objects [1]. Some of these show selected solar system bodies, for which the excellent image sharpness achievable with this new instrument is of special significance. In fact, the VLT photos of the giant planet Saturn and Io, the innermost of Jupiter's four large moons, are among the sharpest ever obtained from the ground . They even compare well with some photos obtained from space, as can be seen via the related weblinks indicated below. The raw NAOS-CONICA data from which these images shown in this Photo Release were produced are now available via the public VLT Science Archive Facility [2]. The NAOS adaptive optics corrector was built, under an ESO contract, by the Office National d'Etudes et de Recherches Aérospatiales (ONERA) , Laboratoire d'Astrophysique de Grenoble (LAOG) and the DESPA and DASGAL laboratories of the Observatoire de Paris in France, in collaboration with ESO. The CONICA infra-red camera was built, under an ESO contract, by the Max-Planck-Institut für Astronomie (MPIA) (Heidelberg) and the Max-Planck Institut für Extraterrestrische Physik (MPE) (Garching) in Germany, in collaboration with ESO. Saturn - Lord of the rings ESO PR Photo 04a/02 ESO PR Photo 04a/02 [Preview - JPEG: 460 x 400 pix - 54k] [Normal - JPEG: 1034 x 800 pix - 200k] Caption : PR Photo 04a/02 shows the giant planet Saturn, as observed with the VLT NAOS-CONICA Adaptive Optics instrument on December 8, 2001; the distance was 1209 million km. It is a composite of exposures in two near-infrared wavebands (H and K) and displays well the intricate, banded structure of the planetary atmosphere and the rings. Note also the dark spot at the south pole at the bottom of the image. One of the moons, Tethys, is visible as a small point of light below the planet. It was used to guide the telescope and to perform the adaptive optics "refocussing" for this observation. More details in the text. Technical information about this photo is available below. This NAOS/CONICA image of Saturn ( PR Photo 04a/02 ), the second-largest planet in the solar system, was obtained at a time when Saturn was close to summer solstice in the southern hemisphere. At this moment, the tilt of the rings was about as large as it can be, allowing the best possible view of the planet's South Pole. That area was on Saturn's night side in 1982 and could therefore not be photographed during the Voyager encounter. The dark spot close to the South Pole is a remarkable structure that measures approximately 300 km across. It was only recently observed in visible light from the ground with a telescope at the Pic du Midi Observatory in the Pyrenees (France) - this is the first infrared image to show it. The bright spot close to the equator is the remnant of a giant storm in Saturn's extended atmosphere that has lasted more than 5 years. The present photo provides what is possibly the sharpest view of the ring system ever achieved from a ground-based observatory . Many structures are visible, the most obvious being the main ring sections, the inner C-region (here comparatively dark), the middle B-region (here relatively bright) and the outer A-region, and also the obvious dark "divisions", including the well-known, broad Cassini division between the A- and B-regions, as well as the Encke division close to the external edge of the A-region and the Colombo division in the C-region. Moreover, many narrow rings can be seen at this high image resolution , in particular within the C-region - they may be compared with those seen by the Voyager spacecraft during the flybys, cf. the weblinks below. This image demonstrates the capability of NAOS-CONICA to observe also extended objects with excellent spatial resolution. It is a composite of four short-exposure images taken through the near-infrared H (wavelength 1.6 µm) and K (2.2 µm) filters. This observation was particularly difficult because of the motion of Saturn during the exposure. To provide the best possible images, the Adaptive Optics system of NAOS was pointed towards the Saturnian moon Tethys , while the image of Saturn was kept at a fixed position on the CONICA detector by means of "differential tracking" (compensating for the different motions in the sky of Saturn and Tethys). This is also why the (faint) image of Tethys - visible south of Saturn (i.e., below the planet in PR Photo 04a/02 ) - appears slightly trailed. Io - volcanoes and sulphur ESO PR Photo 04b/02 ESO PR Photo 04b/02 [Preview - JPEG: 400 x 478 pix - 39k] [Normal - JPEG: 800 x 955 pix - 112k] ESO PR Photo 04c/02 ESO PR Photo 04c/02 [Preview - JPEG: 400 x 469 pix - 58k] [Normal - JPEG: 800 x 937 pix - 368k] Caption : PR Photo 04b/02 shows Io , the volcanic moon of Jupiter, as imaged with the VLT NAOS-CONICA Adaptive Optics instrument on December 5, 2001, through a near-infrared, narrow optical filter (Brackett-gamma at wavelength 2.166 µm). Despite the small angular diameter of Io , about 1.2 arcsec, many features are visible at this excellent optical resolution. PR Photo 04c/02 is a composite of the same exposure with another obtained at a longer wavelength (L'-filter at 3.8 µm), with a latitude-longitude grid superposed and some of the main surface features identified. Technical information about these photos is available below. Io has a diameter of 3660 km and orbits Jupiter at a mean distance of 422,000 km - one revolution takes 42.5 hours. Like the Earth's moon, it always turns the same side towards the planet. As shown by the Voyager spacecraft in 1979, its surface is covered by active volcanoes and lava fields - it is in fact the most volcanic place known in the solar system. Due to this activity, Io's surface is continuously reshaped. The features now seen are all correspondingly young, with a mean age of the order of 1 million years only. The variations in appearance and colour are due to different volcanic deposits of sulphur compounds. The cause of all this activity is Jupiter's strong gravitational pull that leads to enormous stresses inside Io and related heating of the entire moon. PR Photo 04b/02 is a near-infrared NAOS-CONICA image of Io , obtained on December 5, 2001, through a narrow optical filter at wavelength 2.166 µm. The excellent image resolution makes it possible to identify many features on the surface. Some of these are volcanoes, others correspond to lava fields between these. PR Photo 04c/02 is a composite of that image and another obtained at longer wavelength (3.8 µm). A latitute-longitude grid has been superposed, with the most prominent features identified by name, including some of the large volcanoes and sulphurus plains on this very active moon. Io has been observed with the NASA Galileo spacecraft since 1996 at higher resolution in the visible and infrared, especially during close encounters with the satellite (a link to Galileo maps of Io is available below). However, this NAOS image fills a gap in the surface coverage of the infrared images from Galileo. The capability of NAOS/CONICA to map Io in the infrared at the present high image resolution will allow astronomers to continue the survey of the volcanic activity and to monitor regularly the related surface processes . Related sites The following links point to a number of prominent photos of these two objects that were obtained elsewhere. Saturn Voyager images : http://vraptor.jpl.nasa.gov/voyager/vgrsat_img.html HST images : http://hubble.stsci.edu/news_.and._views/pr.cgi.2001+15 Pic du Midi images : http://www.bdl.fr/s2p/saturne.html IfA-CFHT : http://www.ifa.hawaii.edu/ao/images/solarsys/new/new.html Io NASA/Galileo site : http://www.jpl.nasa.gov/galileo/moons/io.html Volcanoes on Io : http://volcano.und.nodak.edu/vwdocs/planet_volcano/Io/Overview.html HST image of Io : http://hubble.stsci.edu/news_.and._views/pr.cgi.1997+21 Keck I image of Io : http://www.astro.caltech.edu/mirror/keck/realpublic/inst/ao/Io/IoSnapshot.jpg Galileo and Voyager maps of Io : http://www.lowell.edu/users/ijw/maps/ (also with names of surface features) Notes [1]: The following astronomers and engineers from ESO and the partner institutes have participated in the current commissioning observations of Saturn and Io with NAOS-CONICA: Wolfgang Brandner, Jean-Gabriel Cuby, Pierre Drossart, Thierry Fusco, Eric Gendron, Markus Hartung, Norbert Hubin, François Lacombe, Anne-Marie Lagrange, Rainer Lenzen, David Mouillet, Claire Moutou, Gérard Rousset, Jason Spyromilio and Gérard Zins . [2]: New archive users may register via the ESO/ST-ECF Archive Registration Form. Technical information about the photos PR Photo 04a/02 is based on four exposures, obtained with VLT YEPUN and NAOS-CONICA on December 8, 2001 (UT). Two of these were made with an H-band filter (10 sec exposure each, wavelength 1.6 µm) and two with a K-band filter (12 sec each, 2.2 µm). The satellite Tethys (diameter 1070 km, orbiting Saturn at a distance of approx. 295,000 km) served as reference source for the Adaptive Optics corrections and the telescope was offset guided to compensate for the differential motion. The frames were reduced in the normal way with classical flats, dark and bias correction. No convolution was made before the two colours were combined to produce the image shown. At the time of the exposure, Saturn was 8.80 AU from the Earth. With a diameter of approx. 120,000 km, its disk subtended an angle of 20.6 arcsec. The nominal resolution of the NAOS-CONICA image, about 0.07 arcsec, thus corresponds to 410 km at Saturn. PR Photo 04b/02 is a reproduction based on a total exposure of 230 sec with VLT YEPUN and NAOS-CONICA on December 5, 2001, made through a Brackett-gamma filter centred at 2.166 µm. The resulting image resolution is 0.068 arcsec. At the moment of the exposure, the distance from the Earth to Io was about 641 million km (4.29 AU) and the image resolution therefore corresponds to approx. 210 km on the surface of the moon. PR Photo 04c/02 is based on a combination of the Brackett-gamma (here rendered as blue) with an L' frame (total exposure 4.2 sec; 3.800 µm; red), superposed with a coordinate grid and with some of the major surface features identified. The grid was produced with tools available at the website of the Institut de Mecanique Celeste et de Calcul des Ephemerides.

  5. Volcano-seismic activity before and after the Maule 2010 Earthquake (Southern Chile): a comparison between Llaima and Villarrica volcanoes

    NASA Astrophysics Data System (ADS)

    Mora-Stock, C.; Thorwart, M.; Wunderlich, T.; Bredemeyer, S.; Rabbel, W.

    2012-04-01

    Llaima and Villarrica are two of the most actives volcanoes in the Southern Volcanic Zone in the Chilean Andes, with different type of activity and edifice. Llaima is a close vent volcano with constant seismic activity, while Villarrica is an open vent volcano with lava lake at the summit and constant degassing. The relation between volcano eruptions following a great earthquake has been studied in different cases around the world, and it has been the case for the 1960 Valdivia earthquake in southern Chile, where Llaima and Villarrica presented eruptions on the following months to years. This study is focused on characterizing the volcano-seismic activity in the months before and after the M8.8 Maule earthquake on the 27th February 2010. Time series for tremors, long period and volcano tectonic events were obtained from the catalogue of the Volcanic Observatory of the Southern Andes (OVDAS in Spanish) and from the continuous record of the SFB 574 temporary volcanic network. In Villarrica volcano, peaks of activity of tremor and long period events were observed months prior to and after the earthquake, followed by degassing activity, which is consistent with an increase in the activity related to fluids (gas and magma). While in Llaima volcano, a high increase in the volcano tectonic activity was observed directly after the earthquake, consistent with a possible structural adjustment response. The values for pressure change and normal stress were calculated for the Maule earthquake (M8.8) giving results two orders of magnitude lower in comparison to the ones obtained for Valdivia earthquake (M9.5). Finally, these changes in the seismic behavior had lasted over a year, than it is possible to state that the Maule earthquake affected Llaima and Villarrica in some way due to static stress, but given the location and the insufficient critical state of both edifices, it was not possible to generate a great eruption.

  6. Eastern Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this SeaWiFS image of eastern Alaska, the Aleutian Islands, Kodiak Island, Yukon and Tanana rivers are clearly visible. Also visible, but slightly hidden beneath the clouds, is a bloom in Bristol Bay. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  7. Shaking up volcanoes

    USGS Publications Warehouse

    Prejean, Stephanie G.; Haney, Matthew M.

    2014-01-01

    Most volcanic eruptions that occur shortly after a large distant earthquake do so by random chance. A few compelling cases for earthquake-triggered eruptions exist, particularly within 200 km of the earthquake, but this phenomenon is rare in part because volcanoes must be poised to erupt in order to be triggered by an earthquake (1). Large earthquakes often perturb volcanoes in more subtle ways by triggering small earthquakes and changes in spring discharge and groundwater levels (1, 2). On page 80 of this issue, Brenguier et al. (3) provide fresh insight into the interaction of large earthquakes and volcanoes by documenting a temporary change in seismic velocity beneath volcanoes in Honshu, Japan, after the devastating Tohoku-Oki earthquake in 2011.

  8. Vent of Sand Volcano

    Vent of sand volcano produced by liquefaction is about 4 ft across in strawberry field near Watsonville. Strip spanning vent is conduit for drip irrigation system. Furrow spacing is about 1.2 m (4 ft) on center....

  9. Geomorphic Consequences of Volcanic Eruptions in Alaska: A Review

    USGS Publications Warehouse

    Waythomas, Christopher F.

    2015-01-01

    Eruptions of Alaska volcanoes have significant and sometimes profound geomorphic consequences on surrounding landscapes and ecosystems. The effects of eruptions on the landscape can range from complete burial of surface vegetation and preexisting topography to subtle, short-term perturbations of geomorphic and ecological systems. In some cases, an eruption will allow for new landscapes to form in response to the accumulation and erosion of recently deposited volcaniclastic material. In other cases, the geomorphic response to a major eruptive event may set in motion a series of landscape changes that could take centuries to millennia to be realized. The effects of volcanic eruptions on the landscape and how these effects influence surface processes has not been a specific focus of most studies concerned with the physical volcanology of Alaska volcanoes. Thus, what is needed is a review of eruptive activity in Alaska in the context of how this activity influences the geomorphology of affected areas. To illustrate the relationship between geomorphology and volcanic activity in Alaska, several eruptions and their geomorphic impacts will be reviewed. These eruptions include the 1912 Novarupta–Katmai eruption, the 1989–1990 and 2009 eruptions of Redoubt volcano, the 2008 eruption of Kasatochi volcano, and the recent historical eruptions of Pavlof volcano. The geomorphic consequences of eruptive activity associated with these eruptions are described, and where possible, information about surface processes, rates of landscape change, and the temporal and spatial scale of impacts are discussed.A common feature of volcanoes in Alaska is their extensive cover of glacier ice, seasonal snow, or both. As a result, the generation of meltwater and a variety of sediment–water mass flows, including debris-flow lahars, hyperconcentrated-flow lahars, and sediment-laden water floods, are typical outcomes of most types of eruptive activity. Occasionally, such flows can be quite large, with flow volumes in the range of 107–109 m3. A review of the lahars generated during the 2009 eruption of Redoubt volcano will illustrate the geomorphic impacts of lahars on stream channels and riparian habitat. Although much work is needed to develop a comprehensive understanding of the geomorphic consequences of volcanic activity in Alaska, this review provides a synthesis of some of the best-studied eruptions and perhaps will serve as a starting point for future work on this topic.

  10. Geomorphic consequences of volcanic eruptions in Alaska: A review

    NASA Astrophysics Data System (ADS)

    Waythomas, Christopher F.

    2015-10-01

    Eruptions of Alaska volcanoes have significant and sometimes profound geomorphic consequences on surrounding landscapes and ecosystems. The effects of eruptions on the landscape can range from complete burial of surface vegetation and preexisting topography to subtle, short-term perturbations of geomorphic and ecological systems. In some cases, an eruption will allow for new landscapes to form in response to the accumulation and erosion of recently deposited volcaniclastic material. In other cases, the geomorphic response to a major eruptive event may set in motion a series of landscape changes that could take centuries to millennia to be realized. The effects of volcanic eruptions on the landscape and how these effects influence surface processes has not been a specific focus of most studies concerned with the physical volcanology of Alaska volcanoes. Thus, what is needed is a review of eruptive activity in Alaska in the context of how this activity influences the geomorphology of affected areas. To illustrate the relationship between geomorphology and volcanic activity in Alaska, several eruptions and their geomorphic impacts will be reviewed. These eruptions include the 1912 Novarupta-Katmai eruption, the 1989-1990 and 2009 eruptions of Redoubt volcano, the 2008 eruption of Kasatochi volcano, and the recent historical eruptions of Pavlof volcano. The geomorphic consequences of eruptive activity associated with these eruptions are described, and where possible, information about surface processes, rates of landscape change, and the temporal and spatial scale of impacts are discussed. A comm