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1

Alaska Volcano Observatory  

NSDL National Science Digital Library

This is the homepage of the Alaska Volcano Observatory, a joint program of the United States 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). Users can access current information on volcanic activity in Alaska and the Kamchatka Penninsula, including weekly and daily reports and information releases about significant changes in any particluar volcano. An interactive map also directs users to summaries and activity notifications for selected volcanoes, or through links to webcams and webicorders (recordings of seismic activity). General information on Alaskan volcanoes includes descriptions, images, maps, bibliographies, and eruptive histories. This can be accessed through an interactive map or by clicking on an alphabetic listing of links to individual volcanoes. There is also an online library of references pertinent to Quaternary volcanism in Alaska and an image library.

2

Alaska Volcano Observatory Monitoring Station  

USGS Multimedia Gallery

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....

2009-12-08

3

Alaska Volcano Observatory Seismic Network Data Availability  

NASA Astrophysics Data System (ADS)

The Alaska Volcano Observatory (AVO) established in 1988 as 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, monitors active volcanoes in Alaska. Thirty-three volcanoes are currently monitored by a seismograph network consisting of 193 stations, of which 40 are three-component stations. The current state of AVO’s seismic network, and data processing and availability are summarized in the annual AVO seismological bulletin, Catalog of Earthquake Hypocenters at Alaska Volcanoes, published as a USGS Data Series (most recent at http://pubs.usgs.gov/ds/467). Despite a rich seismic data set for 12 VEI 2 or greater eruptions, and over 80,000 located earthquakes in the last 21 years, the volcanic seismicity in the Aleutian Arc remains understudied. Initially, AVO seismic data were only provided via a data supplement as part of the annual bulletin, or upon request. Over the last few years, AVO has made seismic data more available with the objective of increasing volcano seismic research on the Aleutian Arc. The complete AVO earthquake catalog data are now available through the annual AVO bulletin and have been submitted monthly to the on-line Advanced National Seismic System (ANSS) composite catalog since 2008. Segmented waveform data for all catalog earthquakes are available upon request and efforts are underway to make this archive web accessible as well. Continuous data were first archived using a tape backup, but the availability of low cost digital storage media made a waveform backup of continuous data a reality. Currently the continuous AVO waveform data can be found in several forms. Since late 2002, AVO has burned all continuous waveform data to DVDs, as well as storing these data in Antelope databases at the Geophysical Institute. Beginning in 2005, data have been available through a Winston Wave Server housed at the USGS in Anchorage. AVO waveform data were added to the Incorporated Research Institutions for Seismology Data Management Center (IRIS-DMC) beginning in 2008 and now includes continuous waveform data from all available AVO seismograph stations in real time. Data coverage is available through the DMC’s Metadata Aggregator.

Dixon, J. P.; Haney, M. M.; McNutt, S. R.; Power, J. A.; Prejean, S. G.; Searcy, C. K.; Stihler, S. D.; West, M. E.

2009-12-01

4

Volcanic Activity in Alaska and Kamchatka: Summary of Events and Response of the Alaska Volcano Observatory, 2004.  

National Technical Information Service (NTIS)

The Alaska Volcano Observatory (AVO) is responsible for monitoring the more than 40 historically active volcanoes of the Aleutian arc. As of December 31, 2004, 27 of these volcanoes are instrumented with seismometers to track earthquake activity, and AVO ...

C. A. Neal R. G. McGimsey J. Dixon D. Melnikov

2005-01-01

5

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

USGS Publications Warehouse

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.

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

2014-01-01

6

Development of Alaska Volcano Observatory Seismic Networks, 1988-2008  

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

7

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

USGS Publications Warehouse

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.

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

2014-01-01

8

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

Microsoft Academic Search

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

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

2006-01-01

9

Volcanic Activity in Alaska and Kamchatka: Summary of Events and Response of the Alaska Volcano Observatory, 2001.  

National Technical Information Service (NTIS)

The Alaska Volcano Observatory (AVO) monitors the more than 40 historically active volcanoes of the Aleutian Arc. Of these, 22 are monitored with short-period seismic instrument networks as of the end of 2001. The AVO core monitoring program also includes...

R. G. McGimsey C. A. Neal O. Girina

2004-01-01

10

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

USGS Publications Warehouse

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.

Neal, Christina A.; McGimsey, Robert G.

1997-01-01

11

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

12

A Summary of the History and Achievements of the Alaska Volcano Observatory.  

NASA Astrophysics Data System (ADS)

Volcanoes of the Aleutian Islands, Kamchatka and the Kurile Islands present a serious threat to aviation on routes from North America to the Far East. On March 27, 1986, an eruption of Augustine Volcano deposited ash over Anchorage and disrupted air traffic in south-central Alaska. The consequences of the colocation of an active volcano and the largest city in Alaska were clearly evident. That event led to a three-way partnership between the US Geological Survey, the University of Alaska Geophysical Institute and the Alaska State Division of Geological and Geophysical Surveys that now maintains a continuous watch through ground instrumentation and satellite imagery providing data from which warnings of eruptions can be issued to airline operators and pilots. The eruption of Redoubt Volcano in December 1989 was AVO's first big test. It spewed volcanic ash to a height of 14,000 m (45,000 feet) and managed to catch KLM 867, a Boeing 747 aircraft in its plume under dark conditions while approaching Anchorage Airport. Further details of the early days of the Alaska Volcano Observatory will be described, along with its recent successes and challenges.

Smith, R. W.

2008-12-01

13

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

USGS Publications Warehouse

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.

McGimsey, Robert G.; Neal, Christina A.

1996-01-01

14

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

NASA Astrophysics Data System (ADS)

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.

Adleman, J. N.

2006-12-01

15

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

USGS Publications Warehouse

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.

McGimsey, Robert G.; Wallace, Kristi L.

1999-01-01

16

A Summary of the History and Achievements of the Alaska Volcano Observatory  

Microsoft Academic Search

Volcanoes of the Aleutian Islands, Kamchatka and the Kurile Islands present a serious threat to aviation on routes from North America to the Far East. On March 27, 1986, an eruption of Augustine Volcano deposited ash over Anchorage and disrupted air traffic in south-central Alaska. The consequences of the colocation of an active volcano and the largest city in Alaska

R. W. Smith

2008-01-01

17

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

NASA Astrophysics Data System (ADS)

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.

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

2006-12-01

18

Hawaiian Volcano Observatory  

USGS Publications Warehouse

Lava from Kilauea volcano flowing through a forest in the Royal Gardens subdivision, Hawai'i, in February 2008. The Hawaiian Volcano Observatory (HVO) monitors the volcanoes of Hawai'i and is located within Hawaiian Volcanoes National Park. HVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Kilauea and HVO at http://hvo.wr.usgs.gov.

Venezky, Dina Y.; Orr, Tim

2008-01-01

19

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

NASA Astrophysics Data System (ADS)

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.

Skoog, R. A.

2007-12-01

20

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)

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.

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

2006-12-01

21

Cascades Volcano Observatory  

NSDL National Science Digital Library

This is the homepage of the United States Geological Survey's (USGS) Cascades Volcano Observatory (CVO). The site features news and events, updates on current activity of Cascade Range volcanoes, and information summaries on each of the volcanoes in the range. There are also hazard assessment reports, maps, and a 'Living with Volcanoes' feature that provides general interest information. A set of menus provides access to more technical information, such as a glossary, information on volcano hydrology, monitoring information, a photo archive, and information on CVO research projects.

2010-09-15

22

The Hawaiian Volcano Observatory  

NSDL National Science Digital Library

The Hawaiian Volcano Observatory (HVO) is part of the Volcano Hazards Program of the U.S. Geological Survey. HVO's origins are rooted in a desire to use scientific methodology to understand the nature of volcanic processes and to reduce their risks to society. The website provides eruption histories and updates of Kilauea, Mauna Loa, Lo' ihi and other Hawaiian volcanoes as well as earthquake hazards, zoning, and seismicity.

23

Long Valley Volcano Observatory  

NSDL National Science Digital Library

This is the homepage of the United States Geological Survey's (USGS) Long Valley Volcano Observatory (LVO). It features a variety of information on the Mono-Inyo Craters volcanic chain in Long Valley Caldera, California. Materials include a current conditions page with status reports, updates and information releases. There is also monitoring data on seismic activity, ground deformation, gases and tree kill, and hydrologic studies. Topical studies include a reference on the most recent eruption in the Inyo chain (about 250 years ago), and information on the Long Valley Exploratory Well. There are also links to USGS fact sheets and other references about the caldera.

24

Mt. Erebus Volcano Observatory  

NSDL National Science Digital Library

The Mt. Erebus Volcano Observatory website offers a plethora of information about the geology, geochemistry, and geophysics research at Mt. Erebus in Antarctica. The site addresses the evolution of Erebus, lava and gas chemistry, seismology, and much more. Students can discover how Mount Erebus's environment changes by examining two day, 30 day, and 365 day records. The Photo Gallery is packed with incredible images of the landscape, geologic features, and the scientific monitoring. Users can view live footage as well as movies of volcanic eruptions and the inner and outer crater. Because the materials are not particularly technical, users can easily learn about volcanology and, more specifically, about scientists' efforts to better understand Mt. Erebus.

25

Yellowstone Volcano Observatory  

NSDL National Science Digital Library

In 2001, the U.S. Geological Survey, Yellowstone National Park, and the University of Utah entered into an agreement that effectively established the Yellowstone Volcano Observatory. Some of the objectives of the Observatory are "to provide seismic, geodetic, and hydrologic monitoring that enables reliable and timely warnings of possible renewed volcanism and related hazards" and "to improve scientific understanding of tectonic and magmatic processes that influence ongoing seismicity and hydrothermal activity." The Web site itself is divided into several major sections that covering collectively all current volcanic and seismic activity in the region, volcanic history in the area, and frequently asked questions. The section dedicated to volcanic monitoring includes real-time and non real-time data on current conditions, along with a monthly summary. The volcanic history section offers a long-form essay (including representative photos) that provides a general overview of the region's turbulent volcanic and seismic history. Finally, the helpful FAQ section covers such topics as the frequency of volcanic eruptions at Yellowstone and the relationship between volcanism and the geysers and hot springs in Yellowstone. [KMG

Geological Survey (U.S.); Utah, University O.; Park, Yellowstone N.

26

Alaska volcanoes guidebook for teachers  

USGS Publications Warehouse

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.

Adleman, Jennifer N.

2011-01-01

27

Eruption of Alaska volcano breaks historic pattern  

USGS Publications Warehouse

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.

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

2009-01-01

28

Cascades Volcano Observatory: Educational Outreach  

NSDL National Science Digital Library

This portal provides access to educational materials produced by the Cascades Volcano Observatory. The items include news and current events, information on current activity of the Cascades volcanoes, and emergency information in the event of an eruption. There are also frequently-asked-questions features, a glossary, and links to reading materials such as fact sheets and reports of the United States Geological Survey (USGS). For educators and students, there are activities, special features, posters, videos, and slide shows.

29

The 2007 Eruption of Pavlof Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Pavlof Volcano on the Alaska Peninsula began to erupt on August 15, 2007 after a 10.7 year repose. Precursor signals consisted of low-frequency earthquakes that began on August 14 and thermal anomalies that were likely coincident with the beginning of the eruption. The mainly strombolian eruptions are occurring from a new vent high on the SE flank of the volcano, separate from the NNE vent that had been active over the last several decades. Seismic activity, monitored by a network of 6 local instruments, consists of low-frequency events, explosion earthquakes, volcanic tremor, and lahar-generated signals. One station, PVV, is located only 220 m from a lahar channel, and lahars generate an easily distinguished high-frequency seismic signal. A commonly observed sequence is an increase in eruptive activity at the vent, accompanied by stronger tremor visible on all stations, and followed 12-30 minutes later by a lahar at PVV. This suggests that the eruption pulse ejects fresh hot material, which melts additional ice and snow to form new lahars. Steam and ash plumes have generally been below 15,000 ft, but rose as high as 20,000 ft on August 29 and 30. AVHRR remote sensing data showed an ash signal on these days, consistent with pilot reports. On August 30 lightning was observed in the plume from Cold Bay, 59 km SW. In response to the eruptions, AVO has been conducting 24 hr per day surveillance. Fieldwork to date has fortified seismic stations, and installed a new webcam, pressure sensor, and electric field meter. Collaborating scientists from the University of Alaska Fairbanks have installed aerosol sampling equipment at four locations, and collaborating scientists from New Mexico Tech have installed lightning detection equipment at four stations surrounding the volcano. Based on recent eruptions of Pavlof in 1981, 1986, 1996, etc., the eruptive activity is likely to last several months and may include one or more episodes of ash columns to heights of 30,000 ft or more. Additional field work is being planned as of this writing. The Alaska Volcano Observatory (AVO) is a cooperative program of the US Geological Survey, the University of Alaska Fairbanks (UAF), and the Alaska Division of Geological and Geophysical Surveys.

McNutt, S. R.

2007-12-01

30

USGS Cascades Volcano Observatory: Maps and Graphics  

NSDL National Science Digital Library

The United States Geological Survey's website for the Cascades Volcano Observatory (CVO) has a host of graphics and maps for the professional volcano researcher or the amateur volcanologist. The maps and graphics are divided into four broad categories, and within each of those categories are dozens and dozens of maps and graphics. The categories include "Hazards, Features, Topics, and Types: Maps and Graphics", "Monitoring: Maps and Graphics", and "Volcano or Region: Maps and Graphics". Visitors should check out "Bachelor", which is in the "Volcano or Region" category, as there is an "Interactive Imagemap" of the Cascade Range Volcanoes. Clicking on any of the images of the volcanoes will reveal a beautiful, aerial photo of the volcano, along with a brief description of the history of the volcano. Additionally, there is a "Planning Your Visit" section that gives online and offline resources to look at before going to the actual volcano.

2010-02-19

31

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

SciTech Connect

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.

Brantley, S.R.

1990-12-01

32

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

Microsoft Academic Search

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

J. J. Sanchez; S. R. McNutt

2003-01-01

33

High-precision earthquake location and three-dimensional P wave velocity determination at Redoubt Volcano, Alaska  

Microsoft Academic Search

Redoubt Volcano, Alaska poses significant volcanic hazard to the Cook Inlet region and overlying flight paths. During and following the most recent eruption in 1989–1990 the Alaska Volcano Observatory deployed up to 10 seismometers to improve real-time monitoring capabilities at Redoubt and continues to produce an annual earthquake catalog with associated arrival times for this volcano. We compute a three-dimensional

Heather R. DeShon; Clifford H. Thurber; Charlotte Rowe

2007-01-01

34

Satellite-based detection and tracking of volcanic ash clouds from the 2008 eruptions of Okmok and Kasatochi volcanoes, Alaska  

Microsoft Academic Search

The 2008 eruptions of Okmok and Kasatochi volcanoes were the largest explosive eruptions in Alaska since at least 1992 and produced volcanic ash and gas clouds that entered the stratosphere. The Alaska Volcano Observatory utilized near-real-time satellite data (AVHRR, GOES, MODIS, MTSAT and OMI) to detect and track these clouds. Satellite data complemented the real-time seismic monitoring of these volcanoes

D. J. Schneider; J. Bailey; J. Dehn

2008-01-01

35

Alaska - Russian Far East connection in volcano research and monitoring  

NASA Astrophysics Data System (ADS)

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.

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

36

Decision Analysis Tools for Volcano Observatories  

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

37

Monitoring and imaging Alaska volcanoes using seismic noise  

NASA Astrophysics Data System (ADS)

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.

Haney, M. M.

2007-12-01

38

Kanaga Volcano, Aleutian Islands, Alaska  

NSDL National Science Digital Library

These images of the Kanaga Volcano show the symmetrical cone which is characteristic of stratovolcanoes. It is also possible to see how the current volcanic edifice has grown inside an older caldera, the remains of ancient Mount Kanaton. References and links to related sites are included.

39

Hawaiian Volcano Observatory 1956 Quarterly Administrative Reports  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

40

Hawaiian Volcano Observatory Seismic Data, January to March 2009.  

National Technical Information Service (NTIS)

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 comple...

J. S. Nakata P. G. Okubo

2010-01-01

41

Hawaiian Volcano Observatory 1960 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

42

Hawaiian Volcano Observatory 1976 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

43

Hawaiian Volcano Observatory 1973 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

44

Hawaiian Volcano Observatory 1970 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

45

Hawaiian Volcano Observatory 1971 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

46

Hawaiian Volcano Observatory 1969 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

47

Hawaiian Volcano Observatory 1958 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

48

Hawaiian Volcano Observatory 1984 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

49

Hawaiian Volcano Observatory 1972 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

50

Hawaiian Volcano Observatory 1968 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

51

Hawaiian Volcano Observatory 1975 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

52

Hawaiian Volcano Observatory 1980 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

53

Hawaiian Volcano Observatory 1961 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

54

Hawaiian Volcano Observatory 1979 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

55

Hawaiian Volcano Observatory 1966 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

56

Hawaiian Volcano Observatory 1981 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

57

Hawaiian Volcano Observatory 1978 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

58

Hawaiian Volcano Observatory 1967 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

59

Hawaiian Volcano Observatory 1985 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

60

Hawaiian Volcano Observatory 1982 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

61

Hawaiian Volcano Observatory 1965 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

62

Hawaiian Volcano Observatory 1957 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

63

Hawaiian Volcano Observatory 1962 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

64

Hawaiian Volcano Observatory 1977 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

65

Hawaiian Volcano Observatory 1983 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

66

Hawaiian Volcano Observatory 1959 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

67

Hawaiian Volcano Observatory 1964 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

68

Hawaiian Volcano Observatory 1963 Quarterly Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

69

Hawaiian Volcano Observatory 1974 Annual Administrative Report  

USGS Publications Warehouse

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.

Compiled by Nakata, Jennifer S.

2007-01-01

70

Seismic Observations of Westdahl volcano and Western Unimak Island Alaska: 1999-2005  

NASA Astrophysics Data System (ADS)

Westdahl volcano is a large basaltic shield volcano on the western end of Unimak Island Alaska in the Aleutian Island Arc. The volcano is topped by three separate vents, Pogromni Volcano, Faris Peak, and Westdahl Peak. The volcano is frequently active with known eruptions from Westdahl Peak in 1964, 1978, and 1991-92 that produced large basaltic lava flows. InSAR measurements indicate that Westdahl Volcano has been inflating at a slowly declining rate since 1992 (Lu et al., 2003). The Alaska Volcano Observatory has operated a network of six short-period seismometers on Westdahl Peak since 1998. Complementing this network are similar networks centered on Shishaldin and Akutan Volcanoes. Since 1999 more than 300 earthquakes have been located within 20 km of Westdahl Volcano. A volcano specific velocity model was determined for the western half of Uminak Island by simultaneously inverting for the velocity model and hypocentral earthquake locations using the program VELEST. Earthquakes located with the new model reveal five clusters of hypocenters: (a) a shallow cluster beneath Westdahl Peak, that largely occurred during a 24-hour period on January 7, 2004, (b) a concentration of 68 earthquakes with hypocenters ranging in depth from zero to eight km beneath Faris Peak occurring continually since 1999, (c) a diffuse cluster of long-period events northwest of Westdahl and Faris Peaks, (d) a cluster of 12 earthquakes near Pinnacle Rock, 12 km southwest of Westdahl Peak in October 2003, and (e) a cluster of 43 hypocenters near Unimak Bight, 20 km east of Westdahl Peak, that occurred between January and April 2004. Focal mechanisms were derived for four earthquakes in the Faris Peak cluster and four additional earthquakes that locate off the volcanic edifice (the four mechanisms are in the Pinnacle Rock cluster, the Unimak Bight cluster, and 20 km southeast and 30 km northeast of the volcano). Focal mechanisms in the Faris Peak cluster showed normal faulting with nodal planes trending north-south to northwest-southeast. Mechanisms of the off-volcano earthquakes are generally characterized by normal faulting with nodal planes trending southwest-northeast. These events are consistent with a stress field dominated by the Aleutian subduction zone. The Faris Peak mechanisms are not consistent with the presumed regional stress field and may reflect volcanic process. Lu et al., (2003) proposed the observed inflation of Westdahl Volcano resulted from a slowly pressurizing magma source at 6 km depth beneath Westdahl Peak. The observed seismicity is consistent with this model. Lu, Z., T. Masterlark, D. Dzurisin, and R. Rykhus, 2003, Magma supply dynamics at Westdahl volcano, Alaska, modeled from satellite radar interferometry, Alaska, J. Geophys. Res. 108, 2354, doi:10.1029/2002JB002311, 2003.

Dixon, J. P.; Power, J. A.; Stihler, S. D.

2005-12-01

71

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

NASA Technical Reports Server (NTRS)

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

2006-01-01

72

Temporal Changes of Vp/Vs Ratios in the Volcano-Tectonic Seismic Swarm Zones of Redoubt Volcano, Alaska  

NASA Astrophysics Data System (ADS)

It is known that the P and S wave velocity ratios, Vp/Vs, reflect the physical and chemical properties of medium including temperature, density, and rock composition. Temporal variations of Vp/Vs ratios in volcanic regions may allow us to infer the changes in medium and magma properties beneath volcanoes. Redoubt volcano is an active volcano that is located at 175 km southwest from Anchorage. The size of volcano is about 10 km in diameter, and the volume is around 30-35 km2. The volcano has erupted several times since 1902, and most recently in 2009. The eruptions were generally explosive, and produced lava and pyroclastic flows. Seismic events in the volcano-tectonic (VT) seismic swarm zones of Redoubt volcano are well monitored by Alaska Volcanic Observatory (AVO). We investigate the Vp/Vs ratios in the VT seismic swarm zones from observed P and S arrival times. The hypocentral information is collected from the AVO seismic catalogue. Seismic data with high signal-to-noise ratios for earthquakes with epicentral distance less than 10 km are selected for analysis. A total of 6425 P and S travel-time pairs is collected. The Vp/Vs ratios are estimated using a modified Wadati method that is based on the S-P differential travel times versus P travel times. The VT seismic swarm zones are discretized by 0.1°-by-0.1° cells. Tomographic Vp/Vs ratio models are calculated before and after the recent eruption. The average Vp/Vs ratio of the study region is determined to be 1.90, which is significantly higher than that of Poisson solids. Also, systematic temporal changes in Vp/Vs ratios are observed around the volcano before and after the eruption.

Jo, E.; Hong, T.

2012-12-01

73

The 2013 Eruptions of Pavlof and Mount Veniaminof Volcanoes, Alaska  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

74

Interferometric synthetic aperture radar studies of Alaska volcanoes  

USGS Publications Warehouse

Interferometric synthetic aperture radar (InSAR) imaging is a recently developed geodetic technique capable of measuring ground-surface deformation with centimeter to subcentimeter vertical precision and spatial resolution of tens-of-meter over a relatively large region (???104 km2). The spatial distribution of surface deformation data, derived from InSAR images, enables the construction of detailed mechanical models to enhance the study of magmatic and tectonic processes associated with volcanoes. This paper summarizes our recent InSAR studies of several Alaska volcanoes, which include Okmok, Akutan, Kiska, Augustine, Westdahl, and Peulik volcanoes.

Lu, Z.; Wicks, Jr. , C.; Power, J.; Dzurisin, D.; Thatcher, W.; Masterlark, T.

2002-01-01

75

Perspective View of Okmok Volcano, Aleutian Islands, Alaska (#1)  

NASA Technical Reports Server (NTRS)

This perspective view shows the caldera of the Okmok volcano in Alaska's Aleutian Islands.

The shaded relief was generated from and draped over an Airsar-derived digital elevation mosaic.

Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena.

2001-01-01

76

Perspective View of Okmok Volcano, Aleutian Islands, Alaska (#2)  

NASA Technical Reports Server (NTRS)

This perspective view shows the caldera of the Okmok volcano in Alaska's Aleutian Islands.

The shaded relief was generated from and draped over an Airsar-derived digital elevation mosaic.

Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena.

2001-01-01

77

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

NASA Technical Reports Server (NTRS)

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

2006-01-01

78

Gas Emissions From Augustine Volcano, Alaska 1995-2006  

Microsoft Academic Search

After nearly 20 years of quiescence, Augustine Volcano in south-central Alaska became restless in May 2005. Unrest continued through December 2005 with increasingly elevated seismicity and a series of small phreatic explosions, culminating in January 2006 with more than a dozen vulcanian eruptions generating large gas and ash plumes, interspersed with lava extrusion in the summit crater. In February and

K. A. McGee; M. P. Doukas; R. G. McGimsey; R. L. Wessels; C. A. Neal

2006-01-01

79

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

USGS Publications Warehouse

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.

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

1995-01-01

80

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

NASA Astrophysics Data System (ADS)

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.

Burgy, M.; Bolton, D. K.

2006-12-01

81

Volcanoes of the Wrangell Mountains and Cook Inlet region, Alaska: selected photographs  

USGS Publications Warehouse

Alaska is home to more than 40 active volcanoes, many of which have erupted violently and repeatedly in the last 200 years. This CD-ROM contains 97 digitized color 35-mm images which represent a small fraction of thousands of photographs taken by Alaska Volcano Observatory scientists, other researchers, and private citizens. The photographs were selected to portray Alaska's volcanoes, to document recent eruptive activity, and to illustrate the range of volcanic phenomena observed in Alaska. These images are for use by the interested public, multimedia producers, desktop publishers, and the high-end printing industry. The digital images are stored in the 'images' folder and can be read across Macintosh, Windows, DOS, OS/2, SGI, and UNIX platforms with applications that can read JPG (JPEG - Joint Photographic Experts Group format) or PCD (Kodak's PhotoCD (YCC) format) files. Throughout this publication, the image numbers match among the file names, figure captions, thumbnail labels, and other references. Also included on this CD-ROM are Windows and Macintosh viewers and engines for keyword searches (Adobe Acrobat Reader with Search). At the time of this publication, Kodak's policy on the distribution of color-management files is still unresolved, and so none is included on this CD-ROM. However, using the Universal Ektachrome or Universal Kodachrome transforms found in your software will provide excellent color. In addition to PhotoCD (PCD) files, this CD-ROM contains large (14.2'x19.5') and small (4'x6') screen-resolution (72 dots per inch; dpi) images in JPEG format. These undergo downsizing and compression relative to the PhotoCD images.

Neal, Christina A.; McGimsey, Robert G.; Diggles, Michael F.

2001-01-01

82

The geologic history of Redoubt Volcano, Alaska  

USGS Publications Warehouse

Redoubt Volcano is a composite cone built on continental crust at the northeast end of the Aleutian arc. Magmas erupted at Redoubt are medium-K calc-alkaline basalts, andesites, and dacites. The eruptive history of the volcano can be divided into four parts: the early explosive stage, early cone-building stage, late cone-building stage, and post-glacial stage. The most silicic products of the volcano were erupted during the early explosive stage about 0.888 Ma and include pumiceous pyroclastic flow deposits, block-and-ash flow deposits, and a dome or shallow intrusive complex. Basalt and basaltic andesite lava flows and scoria and ash flows were produced during the early cone-building stage, which was underway by 0.340 Ma. During the late cone-building stage, andesitic lava flows and block-and-ash flows were emplaced. Airfall deposits produced during post-glacial eruptions are silicic andesite in composition. Since the early cone-building stage, magmas have become progressively more silicic, but none are as silicic as those in the early explosive stage. Limited Pb and Sr isotopic data suggest that Redoubt magmas were contaminated by North American continental crust. ?? 1994.

Till, A. B.; Yount, M. E.; Bevier, M. L.

1994-01-01

83

The Earthscope Plate Boundary Observatory Alaska Region an Overview of Network Operation, Maintenance and Improvement  

NASA Astrophysics Data System (ADS)

UNAVCO has now completed its third year of operation of the 138 continuous GPS stations, 12 tiltmeters and 31 communications relays that comprise the Alaska Region of the Earthscope Plate Boundary Observatory. Working in Alaska has been challenging due to the extreme environmental conditions encountered and logistics difficulties. Despite these challenges we have been able to complete each summer field season with network operation at 95% or better. Throughout the last three years we have analyzed both our successes and failures to improve the quality of our network and better serve the scientific community. Additionally, we continue to evaluate and deploy new technologies to improve station reliability and add to the data set available from our stations. 2011 was a busy year for the Alaska engineering team and some highlights from last year's maintenance season include the following. This spring we completed testing and deployment of the first Inmarsat BGAN satellite terminal for data telemetry at AC60 Shemya Island. Shemya Island is at the far western end of the Aleutian Islands and is one of the most remote and difficult to access stations in the PBO AK network. Until the installation of the BGAN, this station was offline with no data telemetry for almost one year. Since the installation of the BGAN in early April 2011 dataflow has been uninterrupted. This year we also completed the first deployments of Stardot NetCamSC webcams in the PBO Network. Currently, these are installed and operational at six GPS stations in Alaska, with plans to install several more next season in Alaska. Images from these cameras can be found at the station homepages linked to from the UNAVCO website. In addition to the hard work put in by PBO engineers this year, it is important that we recognize the contributions of our partners. In particular the Alaska Volcano Observatory, the Alaska Earthquake Information Center and others who have provided us with valuable engineering assistance and data telemetry in several locations. With their help we have reduced the number of stations that require manual data download to six in the entire Alaska network getting us closer to our goal of 100% auto data archival for the Alaska network.

Enders, M.; Boyce, E. S.; Bierma, R.; Walker, K.; Feaux, K.

2011-12-01

84

The EarthScope Plate Boundary Observatory Alaska Region: Highlights from the 2012 Summer Field Season  

NASA Astrophysics Data System (ADS)

UNAVCO has now completed its fourth year of operation and maintenance of the 138 continuous GPS stations, 12 tiltmeters and 31 data communications relays that comprise the Alaska region of the EarthScope Plate Boundary Observatory (PBO). The successful operation of the autonomous GPS and tiltmeter network in Alaska continues to be a challenge, because of logistics, weather, and other difficulties related to working in Alaska. PBO engineers continue to work on network enhancements to make the stations more robust, while improving overall data quality and station uptime to better serve the EarthScope science community. In the summer of 2012, PBO engineers completed maintenance activities in Alaska, which resulted in a 95% operational status for the Alaska network within PBO. PBO engineers completed a total of 87 maintenance visits in the summer of FY2012, including 62 routine maintenance and 25 unscheduled maintenance visits to GPS and data communications stations. We present a number of highlights and accomplishments from the PBO 2012 summer field season in Alaska, for example the deployment of a newly designed methanol fuel cell at AV35, a critical station that serves as the main repeater for the real time network on Unimak Island. In addition, PBO engineers also completed the installation of three Inmarsat BGAN terminals for data telemetry following successful testing at AC60 Shemya. Lastly, PBO engineers completed scheduled battery replacements at most of the PBO stations on Unimak Island, in collaboration with the USGS/Alaska Volcano Observatory. In addition to routine maintenance and planned station improvements to sites in Alaska, numerous critical repairs were made at stations on Unimak Island and elsewhere to ensure that the PBO network continues to function well and continues to meet the requirements stipulated by the NSF. We also present some of the station failures unique to Alaska, which we encountered during the course of the 2012 field season, as well as a detailed summary of repairs and corrective actions taken to mitigate the risk of station failures in the future.

Enders, M.; Bierma, R. M.; Boyce, E. S.; Willoughby, H.; Fend, M.; Feaux, K.

2012-12-01

85

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

USGS Publications Warehouse

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.

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

1998-01-01

86

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

Microsoft Academic Search

Mount Drum is one of the youngest volcanoes in the subduction-related Wrangell volcanic field (80x200 km) of southcentral\\u000a Alaska. It lies at the northwest end of a series of large, andesite-dominated shield volcanoes that show a northwesterly progression\\u000a of age from 26 Ma near the Alaska-Yukon border to about 0.2 Ma at Mount Drum. The volcano was constructed between 750

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

1994-01-01

87

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

Microsoft Academic Search

Mount Drum is one of the youngest volcanoes in the subduction-related Wrangell volcanic field (80×200 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

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

1994-01-01

88

The Plate Boundary Observatory Permanent Global Positioning System Network on Augustine Volcano Before and After the 2006 Eruption  

USGS Publications Warehouse

In September of 2004, UNAVCO and the National Science Foundation (NSF) funded EarthScope Plate Boundary Observatory (PBO) installed five permanent Continuous Global Positioning System (CGPS) stations on Augustine Volcano, supplementing one existing CGPS station operated by the Alaska Volcano Observatory. All six CGPS stations proved crucial to scientists for detecting and monitoring the precursory deformation of the volcano beginning in early May 2005, as well as for monitoring the many subsequent small inflationary and deflationary episodes that characterized the 2006 eruption. Following the eruption, in September of 2006, PBO added six additional permanent CGPS stations. The 2006 eruption and its precursors were the first significant activity of the volcano in 20 years and the PBO CGPS network provided an unprecedented opportunity to monitor and detect volcanic ground deformation on an erupting Alaskan stratovolcano. Data from the new CGPS stations coupled with the existing seismic stations provided scientists with the first real opportunity to use geodetic data and real time seismic data to assess the volcanic hazards before, during, and after an Alaskan eruption.

Pauk, Benjamin A.; Jackson, Michael; Feaux, Karl; Mencin, David; Bohnenstiehl, Kyle

2010-01-01

89

Evidence for dike emplacement beneath Iliamna Volcano, Alaska in 1996  

USGS Publications Warehouse

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.

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

2004-01-01

90

Hawaiian Volcano Observatory seismic data, January to December 2005  

USGS Publications Warehouse

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.

Nakata, Jennifer S.

2006-01-01

91

Hawaiian Volcano Observatory Seismic Data, January to December 2006  

USGS Publications Warehouse

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.

Nakata, Jennifer

2007-01-01

92

The EarthScope Plate Boundary Observatory Akutan Alaskan Volcano Tiltmeter Installation  

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

93

Snow and ice volume on Mount Spurr Volcano, Alaska, 1981  

USGS Publications Warehouse

Mount Spurr (3,374 meters altitude) is an active volcano 130 kilometers west of Anchorage, Alaska, with an extensive covering of seasonal and perennial snow, and glaciers. Knowledge of the volume and distribution of snow and ice on a volcano aids in assessing hydrologic hazards such as floods, mudflows, and debris flows. In July 1981, ice thickness was measured at 68 locations on the five main glaciers of Mount Spurr: 64 of these measurements were made using a portable 1.7 megahertz monopulse ice-radar system, and 4 measurements were made using the helicopter altimeter where the glacier bed was exposed by ice avalanching. The distribution of snow and ice derived from these measurements is depicted on contour maps and in tables compiled by altitude and by drainage basins. Basal shear stresses at 20 percent of the measured locations ranged from 200 to 350 kilopascals, which is significantly higher than the 50 to 150 kilopascals commonly referred to in the literature as the 'normal' range for glaciers. Basal shear stresses higher than 'normal' have also been found on steep glaciers on volcanoes in the Cascade Range in the western United States. The area of perennial snow and ice coverage on Mount Spurr was 360 square kilometers in 1981, with an average thickness of 190?50 meters. Seasonal snow increases the volume about 1 percent and increases the area about 30 percent with a maximum in May or June. Runoff from Mount Spurr feeds the Chakachatna River and the Chichantna River (a tributary of the Beluga River). The Chakachatna River drainage contains 14 cubic kilometers of snow and ice and the Chichantna River drainage contains 53 cubic kilometers. The snow and ice volume on the mountain was 67?17 cubic kilometers, approximately 350 times more snow and ice than was on Mount St. Helens before its May 18, 1980, eruption, and 15 times more snow and ice than on Mount Rainier, the most glacierized of the measured volcanoes in the Cascade Range. On the basis of these relative quantities, hazard-producing glaciovolcanic phenomena at Mount Spurr could be significantly greater than similar phenomena at Cascade Volcanoes.

March, Rod S.; Mayo, Lawrence R.; Trabant, Dennis C.

1997-01-01

94

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

NASA Astrophysics Data System (ADS)

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.

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

2002-12-01

95

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

National Technical Information Service (NTIS)

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, an...

B. L. Browne M. L. Coombs R. G. McGimsey

2007-01-01

96

InSAR Observation of surface deformation at Augustine volcano, Alaska, 1992- 2006  

Microsoft Academic Search

Augustine volcano is a conical-shaped, active stratovolcano located southwest of Anchorage, Alaska. Augustine volcano experienced eight explosive eruptions in 1812, 1883, 1908, 1935, 1963, 1976, 1986, and most recently, January 2006. To measure ground surface deformation of the Augustine volcano, we applied satellite radar interferometry with European Remote Sensing Satellite 1 and 2 (ERS-1\\/2) and Environment Satellite (ENVISAT) Synthetic Aperture

C. Lee; Z. Lu; O. Kwoun; J. Won

2006-01-01

97

Hawaiian Volcano Observatory Seismic Data, January to December 2007  

USGS Publications Warehouse

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.

Nakata, Jennifer S.; Okubo, Paul G.

2008-01-01

98

Airborne Gas Surveillance of Volcanoes in Western USA and Alaska  

NASA Astrophysics Data System (ADS)

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.

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

2002-05-01

99

The EarthScope Plate Boundary Observatory: Bringing Low Latency Data From Unimak Island, Alaska  

NASA Astrophysics Data System (ADS)

The Plate Boundary Observatory (PBO), part of the NSF-funded EarthScope project, will complete the installation of a fourteen station GPS network on Unimak Island, Alaska in August, 2008. The primary data communications goal of the project is to design and implement a robust data communications network capable of downloading 15-sec daily GPS files and streaming 1 Hz GPS data, via Ustream, from Unimak Island to three data relay points in the Aleutian chain. As part of the permitting agreement with the landowner, PBO will co-locate the GPS stations with existing USGS seismic stations. The technical challenges involved in optimizing the data communications network for both the GPS data and the seismic data will be presented. From Unimak island, there will be three separate data telemetry paths: 1) West through a radio repeater on Akutan volcano to a VSAT in Akutan village, 2) East through a radio repeater to a T1 connection in Cold Bay, AK, 3) South through a radio repeater to a VSAT at an existing PBO GPS station in King Cove, AK. The difficulties involved in the project include complex network geometries with multiple radio repeaters, long distance RF transmission over water, hardware bandwidth limitations, power limitations, space limitations, as well as working in bear country on an incredibly remote and active volcano.

Feaux, K.; Mencin, D.; Jackson, M.; Gallaher, W.; Pauk, B.; Smith, S.

2008-05-01

100

UNAVCO Plate Boundary Observatory 2007 Student Field Assistant Program in the Alaska Region  

NASA Astrophysics Data System (ADS)

The UNAVCO, Inc. Plate Boundary Observatory (PBO) Student Field Assistant Program strives to engage students in further study and careers in the Earth Sciences. Student Field Assistants from a variety of educational backgrounds ranging from high school graduates to master's level students spend a three to five month field season working in tandem with UNAVCO regional Field Engineers. The students work closely with senior staff to reconnaissance, install, and maintain a network of 875 permanent Global Positioning System (GPS) stations in one of the five PBO regions covering the western United States, including Alaska. Practical skills, such as power tool use, drilling, welding, firearms training, and proper field safety procedures, are taught and expected of the students. Installation and maintenance of new and existing GPS stations composes the bulk of the student's responsibilities and duties. When not in the field, students prepare gear and arrange logistics for site installations and maintenance as well as enter metadata and complete installation reports from recently constructed sites. An understanding of the operations of the GPS receivers and the scientific benefit of the network allows for an appreciation and great attention to detail during installation of the sites. Student assistance in the Alaska region during 2007 PBO AK field season was critical to the successful installation of 36 new GPS stations throughout Alaska. Significant benchmarks of the field season included installing six logistically difficult stations in Prince William Sounds, completing the Denali Fault GPS network, four new tiltmeters on Akutan Volcano, completing all installs on the Seward Peninsula as well as several new GPS stations throughout the western interior of the state. Alaska is a prominent area for much movement and deformation as the Pacific Plate subducts beneath the North American Plate resulting in an area of high volcanic activity and heightened crustal deformation. The GPS network that is being constructed aims to better understand much of these earth processes and their effects. To date, the Alaska Region has recently completed its 4th field season and has installed 106 out of a planned 140 stations. During Year 5 of the PBO project, the Alaska PBO regional office will complete the installation of all remaining 34 planned GPS stations including 12 stations on Unimak Island. The 2008 field season will be the last year in the installation phase and will incorporate maintenance of some of the first GPS stations installed in the network during the first and second years of the five year project.

Marzulla, A.; Gasparich, S.; Pauk, B.; Feaux, K.; Jackson, M.

2007-12-01

101

Protocols for geologic hazards response by the Yellowstone Volcano Observatory  

USGS Publications Warehouse

The Yellowstone Plateau hosts an active volcanic system, with subterranean magma (molten rock), boiling, pressurized waters, and a variety of active faults with significant earthquake hazard. Within the next few decades, large and moderate earthquakes and hydrothermal explosions are certain to occur. Volcanic eruptions are less likely, but are ultimately inevitable in this active volcanic region. This document summarizes protocols and tools to be used by the Yellowstone Volcano Observatory (YVO) during earthquakes, volcanic eruptions, hydrothermal explosions or any similar geological activity that could lead to a volcanic eruption. As needed, YVO will be an advisor within the National Incident Management System (NIMS). The YVO Branch within the Operations Section of the Incident Command will consist of three prescribed groups (Monitoring, Information, and Support). The three groups and their subsidiary teams form a scalable system to respond to a variety of scenarios of geological and volcanic unrest. The YVO response will be organized through an event coordination committee, led by the YVO Branch Chief (also known as the Scientist-in-Charge) and consisting of the group supervisors and the existing YVO coordinating scientists. An independent advisory board will work in conjunction with YVO to suggest further avenues for monitoring and research during quiescent periods and will provide scientific oversight to crisis response during unrest. Formal alerts and information statements will be issued by the U.S. Geological Survey (USGS) in conjunction with YVO partners and through standard telephone and Internet ?calldown? lists. External communications will be coordinated by the public information team leader, in association with any Joint Information Center set up through the Incident Command. Internal communications will be handled through a computerized log system that can be used as an archive for public and non-public documents and to provide a forum for discussion by observatory personnel and collaborators. Within 2 months of publication of this document, provisional group supervisors and team leaders will be assigned. The response plan will be updated every three years by the YVO coordinating scientists and will be available through the YVO and USGS public websites. The calldown list will be updated at least once per year and placed on the internal log system.

Yellowstone Volcano Observatory

2010-01-01

102

Hawaiian Volcano Observatory Seismic Data, January to December 2008  

USGS Publications Warehouse

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.

Nakata, Jennifer S.; Okubo, Paul G.

2009-01-01

103

Deformation associated with the 1997 eruption of Okmok volcano, Alaska  

USGS Publications Warehouse

Okmok volcano, located on Umnak Island in the Aleutian chain, Alaska, is the most eruptive caldera system in North America in historic time. Its most recent eruption occurred in 1997. Synthetic aperture radar interferometry shows deflation of the caldera center of up to 140 cm during this time, preceded and followed by inflation of smaller magnitude. The main part of the observed deformation can be modeled using a pressure point source model. The inferred source is located between 2.5 and 5.0 km beneath the approximate center of the caldera and ???5 km from the eruptive vent. We interpret it as a central magma reservoir. The preeruptive period features inflation accompanied by shallow localized subsidence between the caldera center and the vent. We hypothesize that this is caused by hydrothermal activity or that magma moved away from the central chamber and toward the later vent. Since all historic eruptions at Okmok have originated from the same cone, this feature may be a precursor that indicates an upcoming eruption. The erupted magma volume is ???9 times the volume that can be accounted for by the observed preeruptive inflation. This indicates a much longer inflation interval than we were able to observe. The observation that reinflation started shortly after the eruption suggests that inflation spans the whole time interval between eruptions. Extrapolation of the average subsurface volume change rate is in good agreement with the long-term eruption frequency and eruption volumes of Okmok.

Mann, D.; Freymueller, J.; Lu, Z.

2002-01-01

104

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)

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.

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

2009-12-01

105

Holocene Tephrochronology from Lake Sediments, Redoubt Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Lake sediments in volcanically active areas provide a geological archive of tephra-fall events because sedimentation often occurs continuously and organic material for 14C dating is commonly available; lake sediments, therefore, contain valuable information about tephra fall and associated hazards. Recovering tephra-fall records from lakes requires careful site selection, core recovery, and tephra age assignments. 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 ca. 8750 cal yr BP. A previous core taken from a shallow site at Bear Lake contains 38 tephra layers suggesting that a deeper site in lakes provides a more complete sediment record as shallow sites are susceptible to remobilization and have lower sedimentation rates. We use 12 AMS 14C ages, along with the 137Cs and 210Pb activities of the top 8.5 cm of sediment, to evaluate different models to determine the age-depth relation of sediment, and to determine the age of each tephra deposit. The selected age model is based on a cubic smooth spline function that was passed through the adjusted tephra-free depth of each dated layer; the age model provides an example of how best to date lake sediment in a volcanically active area where presumably instantaneous tephra deposition compounds a simple age-depth relationship. Using the age model we find that 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 ca. 2500-3500, 4500-5000, and 7000-7500 cal yr BP. Our record suggests that Bear Lake experienced extended periods (1000-2000 yr) of increased tephra fall between shorter periods (500-1000 yr) of 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 and places recent eruptive activity in context of Holocene volcanism.

Schiff, C. J.; Kaufman, D. S.; Wallace, K. L.

2006-12-01

106

Synthetic aperture radar interferometry of Okmok volcano, Alaska: radar observations  

USGS Publications Warehouse

ERS-1/ERS-2 synthetic aperture radar interferometry was used to study the 1997 eruption of Okmok volcano in Alaska. First, we derived an accurate digital elevation model (DEM) using a tandem ERS-1/ERS-2 image pair and the preexisting DEM. Second, by studying changes in interferometric coherence we found that the newly erupted lava lost radar coherence for 5-17 months after the eruption. This suggests changes in the surface backscattering characteristics and was probably related to cooling and compaction processes. Third, the atmospheric delay anomalies in the deformation interferograms were quantitatively assessed. Atmospheric delay anomalies in some of the interferograms were significant and consistently smaller than one to two fringes in magnitude. For this reason, repeat observations are important to confidently interpret small geophysical signals related to volcanic activities. Finally, using two-pass differential interferometry, we analyzed the preemptive inflation, coeruptive deflation, and posteruptive inflation and confirmed the observations using independent image pairs. We observed more than 140 cm of subsidence associated with the 1997 eruption. This subsidence occurred between 16 months before the eruption and 5 months after the eruption, was preceded by ?18 cm of uplift between 1992 and 1995 centered in the same location, and was followed by ?10 cm of uplift between September 1997 and 1998. The best fitting model suggests the magma reservoir resided at 2.7 km depth beneath the center of the caldera, which was ?5 km from the eruptive vent. We estimated the volume of the erupted material to be 0.055 km3 and the average thickness of the erupted lava to be ?7.4 m. Copyright 2000 by the American Geophysical Union.

Lu, Zhong; Mann, Dörte; Freymueller, Jeffrey T.; Meyer, David J.

2000-01-01

107

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

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

108

Hawaiian Volcano Observatory seismic data, January to March 2009  

USGS Publications Warehouse

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.

Nakata, Jennifer S.; Okubo, Paul G.

2010-01-01

109

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

Microsoft Academic Search

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

K. L. Wallace

2002-01-01

110

Acoustic measurements of the 1999 basaltic eruption of Shishaldin volcano, Alaska  

Microsoft Academic Search

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

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

2004-01-01

111

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

National Technical Information Service (NTIS)

In this report, we describe our current understanding of the hazards associated with Gareloi Volcano. The term hazard refers to danger posed by the physical events during an eruption (or less likely, physical phenomena on the volcano not directly associat...

B. L. Browne M. L. Coombs R. G. McGimsey

2008-01-01

112

Historically Active Volcanoes in Alaska - A Quick Reference  

NSDL National Science Digital Library

This United States Geological Survey (USGS) fact sheet summarizes historical data (from 1760 to 1999) on 41 Alaskan volcanoes, using information drawn from the more thorough and comprehensive USGS Open-File Report 98-582. Summaries include the volcano type, location (latitude and longitude), location on USGS quadrangle map, and any information available about the dates of eruptions and type of volcanic activity that occurred. Some volcanoes covered include Trident, Redoubt, Wrangell, Katmai, Cleveland, Kiska and more. A downloadable, printable version is available.

113

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

USGS Publications Warehouse

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.

Orr, Tim R.; Hoblitt, Richard P.

2008-01-01

114

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)

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.

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

2003-12-01

115

LARGE SCALE EDIFICE COLLAPSE AT REDOUBT VOLCANO, ALASKA  

NASA Astrophysics Data System (ADS)

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.

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

2009-12-01

116

Geology and Late Quaternary Eruptive History of Kanaga Volcano, a Calc-Alkaline Stratovolcano in the Western Aleutian Islands, Alaska  

Microsoft Academic Search

Recent studies of the geology and eruptive history of Kanaga Volcano in the western Aleutian Islands of Alaska have yielded new information about the timing of Holocene eruptions and an improved understanding of the evolution of the volcano. Previous studies indicated that Kanaton Ridge, a major topographic feature on the northern part of Kanaga Island, was the rim of a

Christopher F. Waythomas; Thomas P. Miller; Christopher J. Nye

117

Comparative Spectrograms Between the Popocatepetl Volcano Magnetic Station and the Teoloyucan Magnetic Observatory, Mexico  

Microsoft Academic Search

We present a comparative spectrogram analysis for the Popocatepetl Volcano magnetic station (70.943° N CoLat, 261.363° E, 4029 m) and the Teoloyucan Magnetic Observatory (70.254° N CoLat, 260.807º E, 2280 m) time series between 1997 and 2003. Instrumentation at both sites include a Geometrics G856 proton-precession magnetometer operating at a 60 second sampling rate and is complemented with the magnetic

G. Cifuentes-Nava; J. E. Hernandez-Quintero; E. Cabral-Cano; A. L. Martin-Del Pozzo; R. E. Chavez-Segura

2007-01-01

118

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

USGS Publications Warehouse

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.

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

2000-01-01

119

Earth's Active Volcanoes by Geographic Region  

NSDL National Science Digital Library

This site describes active volcanoes from around the world by using the volcano links from the Michigan Technological University and the homepages of observatories at active volcanoes. Each volcano section contains photo images, maps, and reference text. Some sections contain bibliographies, volcano reports, and video clips of lahars. The volcanoes are organized by the following geographic regions: Africa and surrounding islands; the Southwest Pacific, Southeast Asia, and India; East Asia including Japan and Kamchatka; Antarctica; the North Atlantic and Iceland; the Mediterranean; South America and surrounding islands; Central Pacific, South Pacific and New Zealand; Alaska and the Northern Pacific Region; North America; and Central America.

120

Microearthquakes at St. Augustine Volcano, Alaska, Triggered by Earth Tides  

Microsoft Academic Search

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

F. J. Mauk; J. Kienle

1973-01-01

121

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

USGS Publications Warehouse

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.

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

2013-01-01

122

Spatial variation of seismic b-values beneath Makushin Volcano, Unalaska Island, Alaska  

Microsoft Academic Search

The frequency–magnitude distribution was spatially mapped beneath Makushin Volcano, Unalaska Island, Alaska using an earthquake catalog of 491 events that occurred between July 2001 and April 2005. An area of high seismic b-values (?2.0) is found ?4 km east of Makushin's main vent at a depth between 4 and 7 km. The anomaly is statistically significant based on Utsu's p-test [T. Utsu,

David L. Bridges; Stephen S. Gao

2006-01-01

123

Preliminary volcano hazard assessment for the Emmons Lake volcanic center, Alaska  

USGS Publications Warehouse

The Emmons Lake volcanic center is a large stratovolcano complex on the Alaska Peninsula near Cold Bay, Alaska. The volcanic center includes several ice- and snow-clad volcanoes within a nested caldera structure that hosts Emmons Lake and truncates a shield-like ancestral Mount Emmons edifice. From northeast to southwest, the main stratovolcanoes of the center are: Pavlof Sister, Pavlof, Little Pavlof, Double Crater, Mount Hague, and Mount Emmons. Several small cinder cones and vents are located on the floor of the caldera and on the south flank of Pavlof Volcano. Pavlof Volcano, in the northeastern part of the center, is the most historically active volcano in Alaska (Miller and others, 1998) and eruptions of Pavlof pose the greatest hazards to the region. Historical eruptions of Pavlof Volcano have been small to moderate Strombolian eruptions that produced moderate amounts of near vent lapilli tephra fallout, and diffuse ash plumes that drifted several hundreds of kilometers from the vent. Cold Bay, King Cove, Nelson Lagoon, and Sand Point have reported ash fallout from Pavlof eruptions. Drifting clouds of volcanic ash produced by eruptions of Pavlof would be a major hazard to local aircraft and could interfere with trans-Pacific air travel if the ash plume achieved flight levels. During most historical eruptions of Pavlof, pyroclastic material erupted from the volcano has interacted with the snow and ice on the volcano producing volcanic mudflows or lahars. Lahars have inundated most of the drainages heading on the volcano and filled stream valleys with variable amounts of coarse sand, gravel, and boulders. The lahars are often hot and would alter or destroy stream habitat for many years following the eruption. Other stratocones and vents within the Emmons Lake volcanic center are not known to have erupted in the past 300 years. However, young appearing deposits and lava flows suggest there may have been small explosions and minor effusive eruptive activity within the caldera during this time interval. Mount Hague may have experienced minor steam eruptions. The greatest hazards in order of importance are described below and summarized on plate 1.

Waythomas, Christopher; Miller, Thomas P.; Mangan, Margaret T.

2006-01-01

124

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

USGS Publications Warehouse

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.

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

2000-01-01

125

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

USGS Publications Warehouse

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.

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

2007-01-01

126

Mechanism of the 1996-97 non-eruptive volcano-tectonic earthquake swarm at Iliamna Volcano, Alaska  

USGS Publications Warehouse

A significant number of volcano-tectonic(VT) earthquake swarms, some of which are accompanied by ground deformation and/or volcanic gas emissions, do not culminate in an eruption.These swarms are often thought to represent stalled intrusions of magma into the mid- or shallow-level crust.Real-time assessment of the likelihood that a VTswarm will culminate in an eruption is one of the key challenges of volcano monitoring, and retrospective analysis of non-eruptive swarms provides an important framework for future assessments. Here we explore models for a non-eruptive VT earthquake swarm located beneath Iliamna Volcano, Alaska, in May 1996-June 1997 through calculation and inversion of fault-plane solutions for swarm and background periods, and through Coulomb stress modeling of faulting types and hypocenter locations observed during the swarm. Through a comparison of models of deep and shallow intrusions to swarm observations,we aim to test the hypothesis that the 1996-97 swarm represented a shallow intrusion, or "failed" eruption.Observations of the 1996-97 swarm are found to be consistent with several scenarios including both shallow and deep intrusion, most likely involving a relatively small volume of intruded magma and/or a low degree of magma pressurization corresponding to a relatively low likelihood of eruption. ?? 2011 Springer-Verlag.

Roman, D. C.; Power, J. A.

2011-01-01

127

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

128

Explosion at dormant Alaskan volcano  

NASA Astrophysics Data System (ADS)

The Fourpeaked volcano, which is located in a remote part of Alaska, and which has had no known activity in the last 10,000 years, released ash, gas, and steam on 17 September, according to the Alaska Volcano Observatory (AVO). The volcano has continued to release sulfur dioxide at a rate that is similar to that measured before the January 2006 eruptions of Alaska's Augustine volcano. This indicates there is abundant, new magma within a few kilometers of the surface, said AVO research geophysicist Peter Cervelli of the U.S. Geological Survey. AVO has issued a hazard concern level of `yellow' for the volcano (the volcano previously had no level of concern), warning that the volcano could erupt within the next days, months, or years. The Fourpeaked volcano had been unmonitored. Weather-permitting, AVO plans to soon install on the mountain a web camera, short-period seismometer, and pressure sensor to detect explosions, said Cervelli. Fourpeaked Mountain is located 320 kilometers southwest of Anchorage on the Alaska Peninsula. Additional information is available at http://www.avo.alaska.edu/activity/Fourpeaked.php

Zielinski, Sarah

2006-10-01

129

New Evidence of Tsunamis from Augustine Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Historical records suggest an eruption of Augustine Volcano generated a tsunami as much as 6-9 m high in 1883 when a debris avalanche travelled 6 km into the waters of Cook Inlet. No trace of tsunami deposits from this event has previously been reported from the Cook Inlet area, leading to suggestions that the historical record is in error and that the hazard from future Augustine Volcano tsunamis is minimal. We report here on several sites that appear to provide evidence of the 1883 and older tsunamis. At several sites on Augustine Island, the 1883 debris-avalanche deposit is overlain by water-rounded pumice, shells, and sands recording wave action at elevations more than 9 m above MSL. At the native village of Nanwalek, 80 km east of Augustine, we found sand, water-rounded cobbles and granules buried by Augustine 1883 tephra, consistent with reports by observers in 1883. The Augustine deposits underlie Katmai 1912 tephra and a sheet of sand and cobbles deposited by the well-documented tsunami of the 1964 Alaskan earthquake. Dendrochronologic evidence indicates that a sand horizon intercalated with peat at the Red River on the mainland north of Augustine also dates to 1883. We also report evidence for a second volcanic tsunami, evidently produced by the ca. 500 ya West Island debris avalanche. A zone of wave-eroded sediment and ash extends to an elevation of more than 15 m above MSL on the southwest side of Augustine Island. At Nanwalek and Seldovia, 80-100 km east of Augustine Volcano, deposits older than 1883 of sand and water-rounded granules occur more than 5 m above MSL, where they are intercalated with numerous tephra layers in peat. We speculate that these deposits may be from a tsunami generated by the West Island debris avalanche.

Beget, J.; Gardner, C.

2002-12-01

130

Comparative Spectrograms Between the Popocatepetl Volcano Magnetic Station and the Teoloyucan Magnetic Observatory, Mexico.  

NASA Astrophysics Data System (ADS)

We present a comparative spectrogram analysis for the Popocatepetl Volcano magnetic station (70.943° N CoLat, 261.363° E, 4029 m) and the Teoloyucan Magnetic Observatory (70.254° N CoLat, 260.807º E, 2280 m) time series between 1997 and 2003. Instrumentation at both sites include a Geometrics G856 proton-precession magnetometer operating at a 60 second sampling rate and is complemented with the magnetic record from a dF fluxgate variograph at the Teoloyucan Magnetic Observatory (TEO). Popocatepetl's total magnetic field record is reconstructed using a harmonic analysis technique, and subtracted to the TEO record, which is considered as a reference site. The resulting difference shows a significant diurnal component, presumably from a local magnetic induction or from ionospheric origin. This is in sharp contrast with our initial considerations for geomagnetic volcano monitoring that considered the distance between both sites to be close enough and assumed similar ionospheric conditions at both sites. This diurnal component influence can be removed using a normalized difference approach or by cancellation during the harmonic reconstruction process. This analysis will improve previously used techniques such as normalized differences or correlation in magnetic data analysis for short, middle and long term active volcano magnetic monitoring.

Cifuentes-Nava, G.; Hernandez-Quintero, J. E.; Cabral-Cano, E.; Martin-Del Pozzo, A. L.; Chavez-Segura, R. E.

2007-05-01

131

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

NASA Astrophysics Data System (ADS)

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.

Wallace, K. L.

2002-12-01

132

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

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).

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

2001-01-01

133

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

PubMed

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

Mauk, F J; Kienle, J

1973-10-26

134

Exploring Means of Determining Surface Deformation at Augustine Volcano  

Microsoft Academic Search

The recent January 2006 eruption of Augustine Volcano followed a nearly a year of increased seismic activity, that has been actively monitored by the Alaska Volcano Observatory (AVO). The eruption has generated a topographical signal that GPS ground stations were able to monitor. This work addresses the question as to which other techniques are able to see this deformation. While

J. T. Lovick; O. Lawlor; K. Dean; J. Dehn; J. Freymueller; D. Atwood

2006-01-01

135

Seismicity and seismic structure at Okmok Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Okmok volcano is an active volcanic caldera located on the northeastern portion of Umnak Island in the Aleutian arc, with recent eruptions in 1997 and 2008. The Okmok area had ~900 locatable earthquakes between 2003 and June 2008, and an additional ~600 earthquakes from the beginning of the 2008 eruption to mid 2009, providing an adequate dataset for seismic tomography. To image the seismic velocity structure of Okmok, we apply waveform cross-correlation using bispectrum verification and double-difference tomography to a subset of these earthquakes. We also perform P-wave attenuation tomography using a spectral decay technique. We examine the spatio-temporal characteristics of seismicity in the opening sequence of the 2008 eruption to investigate the path of magma migration during the establishment of a new eruptive vent. We also incorporate the new earthquake relocations and three-dimensional (3D) velocity model with first-motion polarities to compute focal mechanisms for selected events in the 2008 pre-eruptive and eruptive periods. Through these techniques we obtain precise relocations, a well-constrained 3D P-wave velocity model, and a marginally resolved S-wave velocity model. We image a main low Vp and Vs anomaly directly under the caldera consisting of a shallow zone at 0-2 km depth connected to a larger deeper zone that extends to about 6 km depth. We find that areas of low Qp are concentrated in the central to southwestern portion of the caldera and correspond fairly well with areas of low Vp. We interpret the deeper part of the low velocity anomaly (4-6 km depth) beneath the caldera as a magma body. This is consistent with results from ambient noise tomography and suggests that previous estimates of depth to Okmok's magma chamber based only on geodetic data may be too shallow. The distribution of events preceding the 2008 eruption suggest that a combination of overpressure in the zone surrounding the magma chamber and the introduction of new material from below were jointly responsible for the explosive eruption. Magma escaping from the top of the main magma chamber likely reacted with both a smaller shallow pod of magma and groundwater on its way up below the Cone D area. The earthquakes in the 2008 pre-eruptive and eruptive periods are found to have a mixture of strike-slip, oblique normal, and oblique thrust mechanisms, with a dominant P-axis orientation that is nearly perpendicular to the regional tectonic stress. This may indicate that the stresses related to magmatic activity locally dominated regional tectonic forces during this time period.

Ohlendorf, Summer J.; Thurber, Clifford H.; Pesicek, Jeremy D.; Prejean, Stephanie G.

2014-05-01

136

Andesites of the 2009 eruption of Redoubt Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Crystal-rich andesites that erupted from Redoubt Volcano in 2009 range from 57.5 to 62.5 wt.% SiO2 and have phenocryst and phenocryst-melt relations consistent with staging in the upper crust. Early explosive products are low-silica andesites (LSA, < 58 wt.% SiO2) that ascended from deeper crustal levels during or before the 6 months of precursory activity, but a broad subsequent succession to more evolved and cooler products, and predominantly effusive dome growth, are interpreted to result from progressive mobilization and mixing with differentiated magmas tapped from pre-2009 Redoubt intrusions at ~ 3-6 km depth. Initial explosions on March 23-28 ejected predominantly LSA with a uniform phenocryst assemblage of high-Al amphibole, ~ An70 plagioclase, ortho- and clinopyroxene, FeTi oxides (890 to 960 °C), and traces of magmatic sulfide. Melt in the dominant microlite-poor LSA was compositionally uniform dacite (67-68 wt.% SiO2) but ranged to rhyolite with greater microlite growth. Minor amounts of intermediate- to high-silica andesite (ISA, HSA; 59-62.5 wt.% SiO2) also erupted during the early explosions and most carried rhyolitic melt (72-74 wt.% SiO2). A lava dome grew following the initial tephra-producing events but was destroyed by an explosion on April 4. Ejecta from the April 4 explosion consists entirely of ISA and HSA, as does a subsequent lava dome that grew April 4-July 1; LSA was absent. Andesites from the April 4 event and from the final dome had pre-eruptive temperatures of 725-840 °C (FeTi oxides) and highly evolved matrix liquids (77-80 wt.% SiO2), including in rare microlite-free pyroclasts. ISA has mixed populations of phenocrysts suggesting it is a hybrid between HSA and LSA. The last lavas from the 2009 eruption, effused May 1-July 1, are distinctly depleted in P2O5, consistent with low temperatures and high degrees of crystallization including apatite. Plagioclase-melt hygrometry and comparison to phase equilibrium experiments are consistent with pre-eruptive storage of all three magma types at 100-160 MPa (4-6 km depth), if they were close to H2O-saturation, coincident with the locus of shallow syn-eruptive seismicity. Deeper storage would be indicated if the magmas were CO2-rich. Relatively coarse-grained clinopyroxene-rich reaction rims on many LSA amphibole phenocrysts may result from slow ascent to, or storage at, depths shallow enough for the onset of appreciable H2O exsolution, consistent with pre-eruptive staging in the uppermost crust. We interpret that the 2009 LSA ascended from depth during the 8 or more months prior to the first eruption, but that the magma stalled and accumulated in the upper crust where its phenocryst rim and melt compositions were established. Ascent of LSA through stagnant mushy intrusions residual from earlier Redoubt activity mobilized differentiated magma pockets and interstitial liquids represented by HSA, and as LSA-HSA hybrids represented by ISA, that fed the subsequently erupted lava domes.

Coombs, Michelle L.; Sisson, Thomas W.; Bleick, Heather A.; Henton, Sarah M.; Nye, Chris J.; Payne, Allison L.; Cameron, Cheryl E.; Larsen, Jessica F.; Wallace, Kristi L.; Bull, Katharine F.

2013-06-01

137

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

NASA Astrophysics Data System (ADS)

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.

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

2003-12-01

138

Acoustic measurements of the 1999 basaltic eruption of Shishaldin volcano, Alaska2. Precursor to the Subplinian phase  

Microsoft Academic Search

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 (c2 Hz) lasting 13 h. This bhumming signalQ is interpreted as the coalescence of the very shallow part of a foam building up in the conduit, which produces large gas bubbles

S. Vergniolle; J. Caplan-Auerbach

2004-01-01

139

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

USGS Publications Warehouse

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.

Lee, C. -W.; Lu, Z.; Kwoun, O. -I.; Won, J. -S.

2008-01-01

140

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

141

The New USGS Volcano Hazards Program Web Site  

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

142

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

SciTech Connect

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.

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

1985-01-01

143

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

USGS Publications Warehouse

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.

Fierstein, Judy; Hildreth, Wes

2000-01-01

144

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

USGS Publications Warehouse

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.

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

2004-01-01

145

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

USGS Publications Warehouse

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.

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

2002-01-01

146

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

USGS Publications Warehouse

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.

Nakata, Jennifer S.

2001-01-01

147

Anhydrite in the 1989 1990 lavas and xenoliths from Redoubt Volcano, Alaska  

NASA Astrophysics Data System (ADS)

The eruption of Redoubt Volcano in Alaska produced a moderate sulfur emission (estimated at 1 × 10 tons SO 2), but relatively small volume of lava (0.11 km ) with pre-eruption estimates of 840-950 °C and fO 21.5 to 2.0 log units above NNO (Swanson, S.E., Nye, C.J., Miller, T.P., Avery, V.F., 1994. Magma mixing in the 1989-1990 eruption of Redoubt Volcano: Part II. Evidence from mineral and glass chemistry. Journal of Volcanology and Geothermal Research 62, 453-468). Petrologic estimates of sulfur production (Sigurdsson, H., Devine, J.D.,Davis, A.N., 1985. The petrologic estimation of volcanic degassing. Jokull 35, 1-8) from this eruption (Gerlach, T., Westrich, H.R., Casadevall, T.J., Finnegan, D.L., 1994. Vapor Saturation and accumulation in magmas of the 1989-1990 eruption of Redoubt Volcano, Alaska. Journal of Volcanology and Geothermal Research 62, 317-337) are considerably less than the measured sulfur emission, leading workers to propose the existence of a pre-eruption vapor phase to explain the "excess" sulfur. Initial examination of the 1989-1990 Redoubt eruptive products reported anhydrite (Nye, C.J., Swanson, S.E., Avery, V.F., Miller, T.P., 1994. Geochemistry of the 1989-1990 eruption of Redoubt Volcano: Part I, whole-rock, major- and trace-element chemistry. Journal of Volcanology and Geothermal Research 62, 429-452.) in interstitial glass from some cognate gabbroic xenoliths, but anhydrite was not noted in any of the andesites. A Boeing 747 encountered the ash plume from the initial eruptive phase on December 15, 1989 and provided ash samples that reportedly contained gypsum (Bayhurst, G.K., Wohletz, K.H., Mason, A.S., 1994. A method for characterizing volcanic ash from the December 15, 1989, eruption of Redoubt Volcano, Alaska. U.S. Geological Survey Bulletin 2047, 13-17). However, the identification was based on EDS analyses on a SEM and the mineral could have been anhydrite. Reexamination of the 1989-1990 Redoubt lavas and xenoliths revealed the presence of rare, fine-grained (10s of microns) anhydrite crystals in the lavas and larger (10s to 100s of microns) crystals in the xenoliths. The anhydrite forms elongate crystals with sharp contacts against the groundmass glass. Grains show rounded terminations suggesting breakdown of the anhydrite, perhaps during eruption. The anhydrite is a sparse phase in the lavas, but occurs in lavas and cognate xenoliths erupted throughout the eruption. The presence and breakdown of anhydrite may explain the "excess" sulfur associated with the Redoubt eruption. A careful search of other freshly erupted andesitic lavas solidified from hydrous, oxidizing magmas should reveal other examples of anhydrite and cause a rethinking of the source of sulfur in volcanic emissions.

Swanson, S. E.; Kearney, C. S.

2008-08-01

148

Volcanoes  

NSDL National Science Digital Library

Create a poster about volcanoes Directions: Make a poster about volcanoes. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about volcanoes. (5 points each) (15 points) Write at least a three sentence summary of your poster and volcanoes. (5 points) Use at ...

Walls, Mrs.

2011-01-30

149

Spatial variation of seismic b-values beneath Makushin Volcano, Unalaska Island, Alaska  

NASA Astrophysics Data System (ADS)

The frequency-magnitude distribution was spatially mapped beneath Makushin Volcano, Unalaska Island, Alaska using an earthquake catalog of 491 events that occurred between July 2001 and April 2005. An area of high seismic b-values (˜ 2.0) is found ˜ 4 km east of Makushin's main vent at a depth between 4 and 7 km. The anomaly is statistically significant based on Utsu's p-test [T. Utsu, On seismicity, in Report of the Joint Research Institute for Statistical Mathematics, Tokyo (1992) 139-157], and is not data processing method or parameter dependent. Interestingly, a recent InSAR interferometric study [Z. Lu, J.A. Power, V.S. McConnell, C. Wicks Jr., D. Dzurism, Preeruptive inflation and surface interferometric coherence characteristics by satellite radar interferometry at Makushin volcano, Alaska: 1993-2000, J. Geophys. Res. 107 (2002) 2266, doi:10.1029/2001JB000970] inferred a surface uplift of about 7 cm during the two-year period prior to October 1995, centered approximately in the area with the observed anomalous b-values. The uplift was caused by the volume increase of an inferred magma chamber at a depth of about 7 km. The close correspondence of the seismic and InSAR observations suggests that the heterogeneous area associated with the observed high b-values is most likely the result of increased crack density associated with the magma chamber. This study demonstrates the effectiveness of combining InSAR and seismological observations in locating magma chambers and areas of high heterogeneity in the crust.

Bridges, David L.; Gao, Stephen S.

2006-05-01

150

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

USGS Publications Warehouse

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 14C ages, along with the 137Cs and 210Pb activities of recent sediment, we evaluated different models to determine the age-depth relation of the core, and to determine the age of each tephra deposit. The selected age model is based on a mixed-effect regression that was passed through the adjusted tephra-free depth of each dated layer. The estimated age uncertainty of the 67 tephras averages ??105 yr (95% confidence intervals). Tephra-fall frequency at Bear Lake was among the highest during the past 500 yr, with eight tephras deposited compared to an average of 3.7/500 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 one every 130 yr. ?? 2007 Elsevier Ltd. All rights reserved.

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

2008-01-01

151

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

NASA Astrophysics Data System (ADS)

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.

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

2012-11-01

152

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

SciTech Connect

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.

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

2007-02-25

153

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

154

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

USGS Publications Warehouse

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.

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

1994-01-01

155

Rheologic and structural controls on the deformation of Okmok volcano, Alaska: FEMs, InSAR, and ambient noise tomography  

Microsoft Academic Search

Interferometric synthetic aperture radar (InSAR) data indicate that the caldera of Okmok volcano, Alaska, subsided more than a meter during its eruption in 1997. The large deformation suggests a relatively shallow magma reservoir beneath Okmok. Seismic tomography using ambient ocean noise reveals two low-velocity zones (LVZs). The shallow LVZ corresponds to a region of weak, fluid-saturated materials within the caldera

Timothy Masterlark; Matthew Haney; Haylee Dickinson; Tom Fournier; Cheryl Searcy

2010-01-01

156

Volcanoes  

ERIC Educational Resources Information Center

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)

Kunar, L. N. S.

1975-01-01

157

Volcanoes  

SciTech Connect

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.

Decker, R.W.; Decker, B.

1989-01-01

158

Volcanoes  

NSDL National Science Digital Library

In this lesson, students investigate the processes that build volcanoes, the types of rocks they create, the factors that influence different eruption types, and the threats volcanoes pose to their surrounding environments. They will also create a notebook of volcano characteristics and use what they have learned to identify physical features and eruption types in some real-life documented volcanic episodes.

2005-01-01

159

Measuring and Modeling Changes in Permafrost Temperature at the UAF Permafrost Observatory in Barrow, Alaska  

NASA Astrophysics Data System (ADS)

In 2001, a Permafrost Observatory was established within the Barrow Environmental Observatory in Barrow, Alaska under the auspices of the International Arctic Research Center of the University of Alaska Fairbanks. The observatory was established at the locations where permafrost temperatures were measured during the 1950s and early 1960s by M. Brewer of the U.S. Geological Survey to compare present permafrost temperatures with those obtained by M. Brewer. Those measurements were of very high quality, with a precision of generally 0.01°C. Comparison of permafrost temperature profiles obtained at the same location by Brewer on October 9, 1950 and by the UAF research group on October 9, 2001 shows that at the 15-meter depth (which is slightly above the depth of annual temperature variations) the permafrost temperature was warmer by 1.2°C in 2001 then in 1950. Since 2001, permafrost temperature at this depth increased additionally by 0.5°C. Most of this latest increase happened after 2005. Similar permafrost temperature dynamics during the last ten years was observed at the UAF Permafrost Observatories in the Prudhoe Bay region and could be explained both by an increase in air temperatures and in the snow depth at these locations. A site-specific numerical model for the Barrow permafrost temperature regime was developed in the GI Permafrost Lab. The model was calibrated using data from shallow (down to one meter) soil temperatures obtained by K. Hinkel at a Barrow site with surface conditions similar to the Brewer site. No data from the Brewer sites were used for the calibration. Comparison of the modeling results and the Brewer's measured data shows an excellent agreement. The daily air temperatures and snow cover thickness during the entire period of measurements (1924-2011) at the Barrow meteorological station were used as input data for this calibrated model. As a result, a time series of daily ground temperatures for the depths between 0 and 200 meters were obtained. Analysis of this time series will be used in this presentation to reveal the effect of changes in air temperature and in snow depth on permafrost temperature and on the active layer thickness. Possible changes in these parameters as a result of the predicted changes in climate during the 21st century will be also presented.

Romanovsky, V. E.; Yoshikawa, K.; Marchenko, S. S.

2012-12-01

160

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

161

Alaska  

NASA Technical Reports Server (NTRS)

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.

2002-01-01

162

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

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

163

Imaging eruption columns from the 2009 eruption of Redoubt Volcano, Alaska using Doppler weather radar  

NASA Astrophysics Data System (ADS)

The U.S. Geological Survey deployed a dedicated volcano-monitoring Doppler weather radar system during the 2009 eruption of Redoubt Volcano, Alaska, enabling the collection of an unprecedented radar data set of seventeen explosive events. Radar reflectivity and radial Doppler velocity measurements were made of the column every 70-90 seconds at a vertical resolution of about 2 km. This temporal frequency is 3-6 times higher than what can be achieved by the national system of weather radars (i.e. NEXRAD), and allows for more robust comparisons with traditional geophysical monitoring data from seismic, pressure sensor, web camera and satellite images. The MiniMax-250C radar detected the eruption columns from explosive events with maximum altitudes of 9-19 km above sea level. We describe the preliminary results on imaging these eruption columns. Most of the explosive events were characterized by high radar reflectivity values of 50-60 dBZ in the central core of the eruption column and proximal cloud, which we interpret to be related to the rapid growth of tephra-ice aggregates. Time-series of radial Doppler velocity images documented the transition from turbulent mixing in the column to more uniform expansion of the proximal cloud. Vertical velocities of the eruption column top were estimated from observation of cloud rise in the reflectivity images and ranged from about 25-60 m/s. The duration of the eruptive events ranged from minutes to tens of minutes. Radar-derived duration estimates did not correlate well with seismic and pressure sensor derived durations. The observed maximum column heights were generally higher (perhaps 20% or more) than would be predicted for the mass eruption rate estimated from the mapped deposits.

Schneider, D. J.; Mastin, L. G.

2011-12-01

164

Synthetic aperture radar interferometry coherence analysis over Katmai volcano group, Alaska  

USGS Publications Warehouse

The feasibility of measuring volcanic deformation or monitoring deformation of active volcanoes using space-borne synthetic aperture radar (SAR) interferometry depends on the ability to maintain phase coherence over appropriate time intervals. Using ERS 1 C band (?? = 5.66 cm) SAR imagery, we studied the seasonal and temporal changes of the interferometric SAR coherence for fresh lava, weathered lava, tephra with weak water reworking, tephra with strong water reworking, and fluvial deposits representing the range of typical volcanic surface materials in the Katmai volcano group, Alaska. For interferograms based on two passes with 35 days separation taken during the same summer season, we found that coherence increases after early June, reaches a peak between the middle of July and the middle of September, and finally decreases until the middle of November when coherence is completely lost for all five sites. Fresh lava has the highest coherence, followed by either weathered lava or fluvial deposits. These surfaces maintain relatively high levels of coherence for periods up to the length of the summer season. Coherence degrades more rapidly with time for surfaces covered with tephra. For images taken in different summers, only the lavas maintained coherence well enough to provide useful interferometric images, but we found only a small reduction in coherence after the first year for surfaces with lava. Measurement of volcanic deformation is possible using summer images spaced a few years apart, as long as the surface is dominated by lavas. Our studies suggest that in order to make volcanic monitoring feasible along the Aleutian arc or other regions with similar climatic conditions, observation intervals of the satellite with C band SAR should be at least every month from July through September, every week during the late spring/early summer or late fall, and every 2-3 days during the winter. Copyright 1998 by the American Geophysical Union.

Lu, Z.; Freymueller, J. T.

1998-01-01

165

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

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

166

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

167

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

USGS Publications Warehouse

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.

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

2002-01-01

168

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

NASA Astrophysics Data System (ADS)

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.

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

169

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

NASA Astrophysics Data System (ADS)

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.

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

2009-12-01

170

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

USGS Publications Warehouse

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.

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

2000-01-01

171

Observations of the Electrical Activity of the Redoubt Volcano in Alaska  

NASA Astrophysics Data System (ADS)

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.

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

172

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

NASA Astrophysics Data System (ADS)

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.

Rader, E. L.; Larsen, J.

2008-12-01

173

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

USGS Publications Warehouse

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.

Casadevall, T. J.

1994-01-01

174

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

USGS Publications Warehouse

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.

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

2010-01-01

175

Variations in eruption style during the 1931 A.D. eruption of Aniakchak volcano, Alaska  

NASA Astrophysics Data System (ADS)

The 1931 A.D. eruption of Aniakchak volcano, Alaska, progressed from subplinian to effusive eruptive style and from trachydacite to basaltic andesite composition from multiple vent locations. Eyewitness accounts and new studies of deposit stratigraphy provide a combined narrative of eruptive events. Additional field, compositional, grain size, componentry, density, and grain morphology data document the influences on changing eruptive style as the eruption progressed. The eruption began on 1 May 1931 A.D. when a large subplinian eruption column produced vesicular juvenile-rich tephra. Subsequent activity was more intermittent, as magma interacted with groundwater and phreatomagmatic ash and lithic-rich tephra was dispersed up to 600 km downwind. Final erupted products were more mafic in composition and the eruption became more strombolian in style. Stratigraphic evidence suggests that two trachydacitic lava flows were erupted from separate but adjacent vents before the phreatomagmatic phase concluded and that basaltic andesite lava from a third vent began to effuse near the end of explosive activity. The estimated total bulk volume of the eruption is 0.9 km 3, which corresponds to approximately 0.3 km 3 of magma. Eruption style changes are interpreted as follows: (1) a decrease in magma supply rate caused the change from subplinian to phreatomagmatic eruption; (2) a subsequent change in magma composition caused the transition from phreatomagmatic to strombolian eruption style. Additionally, the explosion and effusion of a similar magma composition from three separate vents indicates how the pre-existing caldera structure controlled the pathway of shallow magma ascent, thus influencing eruption style.

Nicholson, Robert S.; Gardner, James E.; Neal, Christina A.

2011-10-01

176

1989-90 Eruption of Redoubt Volcano, Alaska, and the First Test Case of a USGS Lahar-Detection System  

NSDL National Science Digital Library

This web page describes the lahars that swept down the Drift River Valley during the 1989-90 eruption of Redoubt Volcano, Alaska, and the testing of a new experimental detection and warning system designed to track lahars and debris flows and to give warning to people downstream. In this case, an oil-storage facility in the Cook Inlet area was at risk. The seismometers used (acoustic-flow monitors) were sensitive to ground vibration at relatively high frequencies. On April 6, 1990 the system did detect and track lahars moving down a valley in real time. The amplitude and ground velocity data are diagrammed.

Clucas, R.; Brantley, S.; Major, J.

177

Volcanoes  

USGS Publications Warehouse

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.

Tilling, Robert I.

1998-01-01

178

Volcanoes  

NSDL National Science Digital Library

This resource provides general information about volcanoes. It illustrates the growth of a volcano, using Paricutin and Mt. St. Helens as examples of an active volcano and a lava dome. The terms extinct and dormant are also discussed. This site provides an explanation of why and how volcanoes form, zones of subduction, mid-ocean ridges, and hot spots. Deadly dangers associated with eruptions are discussed as is the use of a tiltmeter for prediction. The content center lesson describes a possible connection between the lost continent of Atlantis and the island of Santorini. Dissolved gasses in magma and the creation of a lava dome are both demonstrated in the hands-on section.

Johnson, Scott

179

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

NASA Astrophysics Data System (ADS)

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).

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

2011-12-01

180

Seismological evidence for long-term and rapidly accelerating magma pressurization preceding the 2009 eruption of Redoubt Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Successful eruption forecasts are heavily dependent on the recognition of well-established patterns in volcano monitoring data. Therefore, it is critical to develop, in retrospect, an understanding of the physical basis for cases of abnormal precursory behavior, as the basis for (a) a complete understanding of the range of precursory signals that may be expected at a particular volcano and (b) development of new monitoring approaches to detect more subtle signals of the underlying processes responsible for common patterns of seismic unrest. Here, using a hybrid analysis of shear-wave splitting (SWS) and double-couple fault-plane solutions (FPS), we document the timing and nature of local stress field changes in the months to days preceding the 2009 eruption of Redoubt Volcano, Alaska, which was characterized by an abnormally long period of precursory low-frequency seismicity reflected in multiple escalations of alert levels prior to the eruption. We find that an approximately ~90° change in the polarization of fast S-wavelets (?) accompanied the earliest signs of seismic unrest in 2008 and continued through the eruption before diminishing in 2009. A similar change in the orientation of VT FPS occurred 18-48 h prior to the eruption onset on March 23, 2009, but almost two months after a strong increase in the rate of shallow VT earthquakes. Combined, our SWS and FPS results show the earliest-, and latest-known changes in seismic monitoring data, respectively, and are suggestive of a protracted period of slow magma ascent followed by a short period of rapidly increasing magma pressurization beneath the volcano. These results demonstrate the power of a combined stress-field analysis for clarifying the processes driving ambiguous seismic unrest at active volcanoes.

Roman, Diana C.; Gardine, Matthew D.

2013-06-01

181

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

USGS Publications Warehouse

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.

Lu, Z.; Masterlark, T.; Dzurisin, D.

2005-01-01

182

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

NASA Astrophysics Data System (ADS)

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.

Kasatkina, Ekaterina; Koulakov, Ivan; West, Michael

2014-05-01

183

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

USGS Publications Warehouse

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.

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

2004-01-01

184

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

NASA Astrophysics Data System (ADS)

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 3.3×10 7 and 2.9×10 3 m 3/s for the first phase and 1.0×10 8 and 2.2×10 3 m 3/s for the second phase. This gives a mass flux of 1.2×10 3 and 8.7×10 2 kg/s, respectively, for the first and the second Strombolian phases.

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

2004-09-01

185

Petrological and Experimental Constraints on the Recent Magma Plumbing System at Okmok Volcano, Alaska, USA  

NASA Astrophysics Data System (ADS)

The most recent eruption of Okmok volcano, Alaska, USA, occurred in February-May 1997, after ca. 9 yr. period of quiescence. The eruption was mainly Strombolian, producing multiple ash plumes, with heights up to 9000 meters ASL, and a 6-km-long lava flow. Here, we use petrological and experimental data to constrain the recent magma plumbing system at Okmok. The whole-rock composition of the 1997 Okmok basalt is homogeneous, and averages 52.27±0.18 wt.% SiO2. The mineral assemblage includes plagioclase (14 vol.%), olivine (3 vol.%), clinopyroxene (<0.3 vol.%), and Ti-magnetite (<0.3 vol.%). Plagioclase phenocrysts are strongly bi-modal: their cores are calcic (An85-95), whereas the outermost rims (and microlites) are more sodic (An66-68). Similarly, cores of olivine phenocrysts are Mg-rich (Fo83-85), whereas their rims and (microlites) are more Fe-rich (Fo73-76). Glass inclusions in phenocrysts contain ca. 2.5 wt.% volatiles. Compositions of the matrix glass and the outermost rims of phenocrysts are most closely reproduced by phase-equilibria experiments at 1015-1030° C and 62-76 MPa water pressure. Compositions of cores of plagioclase and olivine phenocrysts have not been reproduced in our experiments up to 100 MPa, which suggests that they possibly originated from a deeper source. We tentatively suggest that the basaltic magma erupted in 1997 was first stored at deep depths, and then migrated and re-equilibrated at depths of about 3.3-4.1 km beneath the floor of Okmok caldera. Detailed InSAR studies indicate that the 1997 Okmok eruption was preceded by at least 5 years of a nearly continuous uplift of the caldera floor (Lu et al., 2005 and references therein). The deformation was interpreted as the result of gradual pressurization of a shallow magma reservoir by repetitive magma inputs at a depth of 3.6 km, which agrees well with our petrologic estimates. Our ongoing petrological experiments will be used to further constrain the pre-eruptive conditions for the 1997 Okmok basalt and to estimate probable magma ascent rates during the eruption.

Izbekov, P. E.; Larsen, J. F.; Gardner, J. E.

2005-12-01

186

Volcanoes  

NSDL National Science Digital Library

This module include four problem-based learning scenarios related to volcanoes and emphasize different kinds of volcanic hazards and geologic processes. The four scenarios are: whether to build a new high school in the shadow of a restless volcanic giant, Mt. Rainier; Kilauea in Hawaii shows signs of activity. What are the prospects for the nearby population?; Mt. Hood is starting to act like Mt. St. Helens did in 1980, but Mt. Hood is just 40 miles from the metropalitan area. How might an eruption impact this populated area?; and America's largest volcano in Yellowstone National Park is stirring. Are we facing an eruption as devastating as a nuclear attack? This module is from Exploring the Environment.

187

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

NASA Astrophysics Data System (ADS)

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.

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

2006-07-01

188

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

USGS Publications Warehouse

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.

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

1994-01-01

189

On the absence of InSAR-detected volcano deformation spanning the 1995-1996 and 1999 eruptions of Shishaldin Volcano, Alaska  

USGS Publications Warehouse

Shishaldin Volcano, a large, frequently active basaltic-andesite volcano located on Unimak Island in the Aleutian Arc of Alaska, had a minor eruption in 1995-1996 and a VEI 3 sub-Plinian basaltic eruption in 1999. We used 21 synthetic aperture radar images acquired by ERS-1, ERS-2, JERS-1, and RADARSAT-1 satellites to construct 12 coherent interferograms that span most of the 1993-2003 time interval. All interferograms lack coherence within ???5 km of the summit, primarily due to persistent snow and ice cover on the edifice. Remarkably, in the 5-15 km distance range where interferograms are coherent, the InSAR images show no intrusion- or withdrawal-related deformation at Shishaldin during this entire time period. However, several InSAR images do show deformation associated with a shallow ML 5.2 earthquake located ???14 km west of Shishaldin that occurred 6 weeks before the 1999 eruption. We use a theoretical model to predict deformation magnitudes due to a volumetric expansion source having a volume equivalent to the 1999 erupted volume, and find that deformation magnitudes for sources shallower than 10 km are within the expected detection capabilities for interferograms generated from C-band ERS 1/2 and RADARSAT-1 synthetic aperture radar images. We also find that InSAR images cannot resolve relatively shallow deformation sources (1-2 km below sea level) due to spatial gaps in the InSAR images caused by lost coherence. The lack of any deformation, particularly for the 1999 eruption, leads us to speculate that magma feeding eruptions at the summit moves rapidly (at least 80m/day) from >10 km depth, and that the intrusion-eruption cycle at Shishaldin does not produce significant permanent deformation at the surface.

Moran, S. C.; Kwoun, O.; Masterlark, T.; Lu, Z.

2006-01-01

190

Volcanoes in the Infrared  

NSDL National Science Digital Library

In this video adapted from KUAC-TV and the Geophysical Institute at the University of Alaska, Fairbanks, satellite imagery and infrared cameras are used to study and predict eruptions of volcanoes in the Aleutian Islands, Alaska.

Foundation, Wgbh E.

2009-02-27

191

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

USGS Publications Warehouse

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.

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

1999-01-01

192

Gas emissions from failed and actual eruptions from Cook Inlet Volcanoes, Alaska, 1989–2006  

Microsoft Academic Search

Cook Inlet volcanoes that experienced an eruption between 1989 and 2006 had mean gas emission rates that were roughly an order\\u000a of magnitude higher than at volcanoes where unrest stalled. For the six events studied, mean emission rates for eruptions\\u000a 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

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

2011-01-01

193

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

USGS Publications Warehouse

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.

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

2009-01-01

194

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

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.

Doukas, Michael P.; McGee, Kenneth A.

2007-01-01

195

Long term volcano monitoring by using advanced Persistent Scatterer SAR Interferometry technique: A case study at Unimak Island, Alaska  

NASA Astrophysics Data System (ADS)

Unimak Island, the largest island in the eastern Aleutians of Alaska, is home to three major active volcanoes: Shishaldin, Fisher, and Westdahl. Shishaldin and Westdahl erupted within the past 2 decades and Fisher has shown persistent hydrothermal activity (Mann and Freymueller, 2003). Therefore, Unimak Island is of particular interest to geoscientists. Surface deformation on Unimak Island has been studied in several previous efforts. Lu et al. (2000, 2003) applied conventional InSAR techniques to study surface inflation at Westdahl during 1991 and 2000. Mann and Freymueller (2003) used GPS measurements to analyze inflation at Westdahl and subsidence at Fisher during 1998-2001. Moran et al., ( 2006) reported that Shishaldin, the most active volcano in the island , experienced no significant deformation during the 1993 to 2003 period bracketing two eruptions. In this paper, we present deformation measurements at Unimak Islank during 2003-2010 using advanced persistent scatterer InSAR (PSI). Due to the non-urban setting in a subarctic environment and the limited data acquisition, the number of images usable for PSI processing is limited to about 1-3 acquisitions per year. The relatively smaller image stack and the irregular acquisition distribution in time pose challenges in the PSI time-series processing. Therefore, we have developed a modified PSI technique that integrates external atmospheric information from numerical weather predication models to assist in the removal of atmospheric artifacts [1]. Deformation modeling based on PSI results will be also presented. Our new results will be combined with previous findings to address the magma plumbing system at Unimak Island. 1) W. Gong, F. J. Meyer (2012): Optimized filter design for irregular acquired data stack in Persistent Scatterers Synthetic Aperture Radar Interferometry, Proceeding of Geosciences and Remote Sensing Symposium (IGARSS), 2012 IEEE International, Munich, Germany.

Gong, W.; Meyer, F. J.; Freymueller, J. T.; Lu, Z.

2012-12-01

196

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

USGS Publications Warehouse

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.

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

2011-01-01

197

Alaska  

NASA Technical Reports Server (NTRS)

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

2002-01-01

198

UNIT, ALASKA.  

ERIC Educational Resources Information Center

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…

Louisiana Arts and Science Center, Baton Rouge.

199

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

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

200

Lava Flow Mapping at Westdahl Volcano, Alaska, Using SAR and Optical Satellite Imagery  

NASA Astrophysics Data System (ADS)

Field mapping of young lava flows at Aleutian volcanoes is logistically difficult. Optical imaging systems, whether air- or space-borne, can be valuable to such mapping efforts, but are often inhibited by persistent cloud cover in this area. These factors have resulted in erroneous estimates of the area and volume calculations of three young lava flows at Westdahl volcano, including its most recent flow (1991-1992). We combined synthetic aperture radar (SAR) data with multispectral Landsat-7 ETM+ imagery to distinguish among the 1991-1992 flow, the 1964 flow, and a pre-1964 flow, and to calculate the flow areas (8.4 km2, 9.2 km2, and 7.3 km2, respectively). By differencing a USGS digital elevation model (DEM) produced in the 1970-80s with a DEM derived from the Shuttle Radar Topography Mission (February 2000), we estimated the average thickness of the 1991-92 flow to be 13 m (± 5 m), which reasonably agrees with field observations of 5 m ~ 10 m. Lava-flow maps produced in this way can be used to augment 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.

Rykhus, R.; Lu, Z.; Masterlark, T.; Dean, K. G.

2004-12-01

201

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

USGS Publications Warehouse

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.

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

2010-01-01

202

Geological and seismological evidence of increased explosivity during the 1986 eruptions of Pavlof volcano, Alaska  

USGS Publications Warehouse

We present results of study of the best-documented eruptions of Pavlof volcano in historic time. The 1986 eruptions were mostly Strombolian in character; a strong initial phase may have been Vulcanian. The 1986 activity erupted at least 8??106 m3 of feldspar-phyric basaltic andesite lava (SiO2=53-54%), and a comparable volume of wind-borne tephra. During the course of the eruption, 5300 explosion earthquakes occurred, the largest of which was equivalent to an ML=2.5 earthquake. Volcanic tremor was recorded for 2600 hours, and the strongest tremor was recorded out to a distance of 160 km and had an amplitude of at least 54 cm2 reduced displacement. The 1986 eruptions modified the structure of the vent area for the first time in over two decades. A possible pyroclastic flow was observed on 19 June 1986, the first time such a phenomenon has been observed at the volcano. Overall, the 1986 eruptions were the strongest and longest duration eruptions in historic time, and changed a temporal pattern of activity that had persisted from 1973-1984. ?? 1991 Springer-Verlag.

McNutt, S. R.; Miller, T. P.; Taber, J. J.

1991-01-01

203

Volcanoes: Nature's Caldrons Challenge Geochemists.  

ERIC Educational Resources Information Center

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.…

Zurer, Pamela S.

1984-01-01

204

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

USGS Publications Warehouse

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.

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

2002-01-01

205

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

206

Alaska  

NASA Technical Reports Server (NTRS)

Lower elevations are thawing out, while higher mountain ranges are still covered in snow in this MODIS image of Alaska from May 14, 2002. At right, the Aleutian Range falls along Alaska's eastern coastline. At upper right, a thin white line traversing generally south-southwest across the state is the Yukon River, still mostly frozen, although the high-resolution image shows a few dark places along the river's length that could be thawed. Sediment fills the waters along the southwestern coastline, with some blue-green color that could be phytoplankton, as well.

2002-01-01

207

The Electronic Volcano  

NSDL National Science Digital Library

The Electronic Volcano offers links to many types of information on active volcanoes, such as maps, photographs, full texts of dissertations and a few elusive documents. The Electronic Volcano will guide you to resources in libraries or resources on other information servers including catalogs of active volcanoes, datasets for literature citations, electronic and hard-copy journals, visual information, maps, observatories and institutions, and a volcano name and country index.

208

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

NASA Astrophysics Data System (ADS)

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.

Morris, K.; Jeffries, M.

2008-12-01

209

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

USGS Publications Warehouse

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.

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

210

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

USGS Publications Warehouse

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.

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

211

Evolution of the December 14, 1989 precursory long-period event swarm at Redoubt volcano, Alaska  

USGS Publications Warehouse

The intermittency pattern and evolution in waveforms of long-period (LP) seismic events during the intense, 23-h swarm that preceded the December 14, 1989 eruption of Redoubt volcano are investigated. Utilizing cross correlation to exploit the high degree of similarity among waveforms, a substantially more complete event catalog is generated than was available from near realtime detection based on short-term/long-term amplitude ratios, which was saturated by the high rate of activity. The temporal magnitude distribution of the predominant LP events is found to have an unusual banded structure in which the average magnitude of each band slowly increases and then decreases through time. A bifurcation that appears in the uppermost band shortly after the peak in magnitudes is characterized by a quasi-periodicity in intermittency and magnitude that is reminiscent of one of the classic routes to chaotic behavior in some non-linear systems. The waveforms of the predominant events evolve slowly but unsteadily through time. These gradual changes appear to result from variations in the relative amplitudes of spectral peaks that remain stable in frequency, which suggests that they are due to differential excitation of a single, resonant source. Two other previously unrecognized, repetitive waveforms are also identified, but the signals from these secondary events are not clearly recorded at distances beyond the closest station. Similarities among the spectra of the predominant and secondary events suggest that the signals from these events also could represent different modes of exciting the same source. Significant changes in the rates and the sizes of the largest of these secondary events appear to coincide with the peak in the size distribution of the predominant LPs. At least some of the non-repetitive LP waveforms in the swarm appear to be the result of the superposition of signals from the rapid repetition of predominant LP source, thus placing a constraint on the repeat time of the triggering mechanism for this source. A lone hybrid event, which has a waveform character intermediate between the predominant LP events and high-frequency volcano-tectonic events, was also identified in the swarm; the occurrence of this event provides important evidence that the low-frequency character of the LP events is a source rather than a path or site effect. ?? 2001 Elsevier Science B.V. All rights reserved.

Stephens, C. D.; Chouet, B. A.

2001-01-01

212

Alaska  

... lights when viewing the image on a computer screen. The Yukon River is seen wending its way from upper left to lower right. A forest ... June 25, 2000 - Western Alaska with the Yukon River and forest fire smoke plume. project:  MISR ...

2013-04-18

213

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

USGS Publications Warehouse

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. ?? 1994.

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

1994-01-01

214

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

USGS Publications Warehouse

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.

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

2004-01-01

215

The 1999 eruption of Shishaldin Volcano, Alaska: Monitoring a distant eruption  

USGS Publications Warehouse

Shishaldin Volcano, in the central Aleutian volcanic arc, became seismically restless during the summer of 1998. Increasing unrest was monitored using a newly installed seismic network, weather satellites, and rare local visual observations. The unrest culminated in large eruptions on 19 April and 22-23 April 1999. The opening phase of the 19 April eruption produced a sub-Plinian column that rose to 16 km before rapidly dissipating. About 80 min into the 19 April event we infer that the eruption style transitioned to vigorous Strombolian fountaining. Exceptionally vigorous seismic tremor heralded the 23 April eruption, which produced a large thermal anomaly observable by satellite, but only a modest, 6-km-high plume. There are no ground-based visual observations of this eruption; however we infer that there was renewed, vigorous Strombolian fountaining. Smaller low-level ash-rich plumes were produced through the end of May 1999. The lava that erupted was evolved basalt with about 49% SiO2. Subsequent field investigations have been unable to find a distinction between deposits from each of the two major eruptive episodes.

Nye, C. J.; Keith, T. E. C.; Eichelberger, J. C.; Miller, T. P.; McNutt, S. R.; Moran, S.; Schneider, D. J.; Dehn, J.; Schaefer, J. R.

2002-01-01

216

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

217

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

USGS Publications Warehouse

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.

Keith, Terry E. C.

1995-01-01

218

Yellowstone Volcano Observatory  

NSDL National Science Digital Library

This source is a clearinghouse of scientific information about the Yellowstone volcanic system. Topics include recent seismic and thermal activity, volcanic history, references and maps, a photo gallery, and FAQs. This website contains both general information that would be useful for anyone that is seeking information on the Yellowstone volcanic system, as well as more specific resources for geology students or teachers.

Survey, U. S.

219

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)

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.

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

2013-12-01

220

Dante's Volcano  

NASA Technical Reports Server (NTRS)

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.

1994-01-01

221

Operational Monitoring of Volcanoes Using Keyhole Markup Language  

NASA Astrophysics Data System (ADS)

Volcanoes are some of the most geologically powerful, dynamic, visually appealing structures on the Earth's landscape. Volcanic eruptions are hard to predict, difficult to quantify and impossible to prevent, making effective monitoring a difficult proposition. In Alaska, volcanoes are an intrinsic part of the culture, with over 100 volcanoes and volcanic fields that have been active in historic time monitored by the Alaska Volcano Observatory (AVO). Observations and research are performed using a suite of methods and tools in the fields of remote sensing, seismology, geodesy and geology, producing large volumes of geospatial data. Keyhole Markup Language (KML) offers a context in which these different, and in the past disparate, data can be displayed simultaneously. Dynamic links keep these data current, allowing it to be used in an operational capacity. KML is used to display information from the aviation color codes and activity alert levels for volcanoes to locations of thermal anomalies, earthquake locations and ash plume modeling. The dynamic refresh and time primitive are used to display volcano webcam and satellite image overlays in near real-time. In addition a virtual globe browser using KML, such as Google Earth, provides an interface to further information using the hyperlink, rich- text and flash-embedding abilities supported within object description balloons. By merging these data sets in an easy to use interface, a virtual globe browser provides a better tool for scientists and emergency managers alike to mitigate volcanic crises.

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

2007-12-01

222

Eruption of Shiveluch Volcano, Kamchatka Peninsula  

NASA Technical Reports Server (NTRS)

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.

2007-01-01

223

Particle morphologies and formation mechanisms of fine volcanic ash aerosol collected from the 2006 eruption of Augustine Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Fine volcanic ash aerosol (35-0.09um) erupted in 2006 by Augustine Volcano, southwest of Anchorage, Alaska was collected by a DRUM cascade impactor and analyzed by scanning electron microscopy for individual particle chemistry and morphology. Results of these analyses show ash particles occur as either individual glass shard and mineral phase (plagioclase, magnetite, ilmenite, hornblende, etc.) particles or aggregates thereof. Individual glass shard ash particles are angular, uniformly-sized, consist of calc-alkaline whole-rock elements (Si, Al, Fe, Na, and Ca) and are not collocated on the sample media with non-silicate, Cl and S bearing sea salt particles. Aggregate particles occur as two types: pure ash aggregates and sea salt-cored aggregates. Pure ash aggregates are made up of only ash particles and contain no other constituents. Sea salt-cored aggregates are ash particles commingled with sea salts. Determining the formation processes of the different ash particle types need further investigation but some possibilities are proposed here. Individual ash particles may exist when the ambient air is generally dry, little electrical charge exists on ash particles, the eruptive cloud is generally dry, or the number of individual particles exceeds the scavenging capacity of the water droplets present. Another possibility is that ash aggregates may break apart as relative humidity drops over time and causes ash-laden water droplets to evaporate and subsequently break apart. Pure ash aggregates may form when the ambient air and plume is relatively dry but the ash has a significant charge to cause ash to aggregate. Or they could form during long-range transport when turbulent or Brownian motion can cause ash particles to collide and coagulate. Pure ash aggregates could also form as a result of water droplet scavenging and subsequent evaporation of water droplets, leaving behind only ash. In this case, droplets would not have interacted with a sea salt-containing boundary layer. Sea salt-cored aggregates could form when ash particles travel over a maritime environment and sea salt aerosol could easily be incorporated in the plume from the surrounding atmosphere. When the particles are sampled, pressure drops within the DRUM impactor cause the water in the droplet to evaporate, leaving behind ash aggregated with salt

Rinkleff, P. G.; Cahill, C. F.

2010-12-01

224

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

USGS Publications Warehouse

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.

Vergniolle, S.; Caplan-Auerbach, J.

2004-01-01

225

Alaska  

USGS Publications Warehouse

Alaska is the United States' only Arctic region. Its marine, tundra, boreal (northern) forest, and rainforest ecosystems differ from most of those in other states and are relatively intact. Alaska is home to millions of migratory birds, hundred of thousands of caribou, some of the nation's largest salmon runs, a significant proportion of he nation's marine mammals, and half of the nation's fish catch. Energy production is the main driver of the state's economy, providing more than 80% of state government revenue and thousands of jobs. Continuing pressure for oil, gas, and mineral development on land and offshore in ice-covered waters increases the demand for infrastructure, placing additional stresses on ecosystems. Land-based energy exploration will be affected by a shorter season when ice roads are viable, yet reduced sea ice extent may create more opportunity for offshore development. Climate also affects hydropower generation. Mining and fishing are the second and third largest industries in the state, with tourism rapidly increasing the 1990s. Fisheries are vulnerable to changes in fish abundance and distribution that result from both climate change and fishing pressure. Tourism might respond positively to warmer springs and autumns but negatively to less favorable conditions for winter activities and increased summer smoke from wildfire. Alaska is home to 40% (229 of 566) of the federally recognized tribes in the United States. The small number of jobs, high cost of living, and rapid social change make rural, predominantly Native, communities highly vulnerable to climate change through impacts on tradition hunting and fishing and cultural connection to the land and sad. Because most of these communities re not connected to the state's road system or electrical grid, the cost of living is high, and it is challenging to supply good, fuel, materials, health care, and other services. Climate impacts on these communities are magnified by additional social and economic stresses. However, Alaskan Native communities have for centuries dealt with scarcity and high environmental variability and thus have deep cultural reservoirs of flexibility and adaptability.

Chapin, F. Stuart, III; Trainor, Sarah F.; Cochran, Patricia; Huntington, Henry; Markon, Carl; McCammon, Molly; McGuire, A. David; Serreze, Mark

2014-01-01

226

Technical-Information Products for a National Volcano Early Warning System  

USGS Publications Warehouse

Introduction Technical outreach - distinct from general-interest and K-12 educational outreach - for volcanic hazards is aimed at providing usable scientific information about potential or ongoing volcanic activity to public officials, businesses, and individuals in support of their response, preparedness, and mitigation efforts. Within the context of a National Volcano Early Warning System (NVEWS) (Ewert et al., 2005), technical outreach is a critical process, transferring the benefits of enhanced monitoring and hazards research to key constituents who have to initiate actions or make policy decisions to lessen the hazardous impact of volcanic activity. This report discusses recommendations of the Technical-Information Products Working Group convened in 2006 as part of the NVEWS planning process. The basic charge to the Working Group was to identify a web-based, volcanological 'product line' for NVEWS to meet the specific hazard-information needs of technical users. Members of the Working Group were: *Marianne Guffanti (Chair), USGS, Reston VA *Steve Brantley, USGS, Hawaiian Volcano Observatory HI *Peter Cervelli, USGS, Alaska Volcano Observatory, Anchorage AK *Chris Nye, Division of Geological and Geophysical Surveys and Alaska Volcano Observatory, Fairbanks AK *George Serafino, National Oceanic and Atmospheric Administration, Camp Springs MD *Lee Siebert, Smithsonian Institution, Washington DC *Dina Venezky, USGS, Volcano Hazards Team, Menlo Park CA *Lisa Wald, USGS, Earthquake Hazards Program, Golden CO

Guffanti, Marianne; Brantley, Steven R.; Cervelli, Peter F.; Nye, Christopher J.; Serafino, George N.; Siebert, Lee; Venezky, Dina Y.; Wald, Lisa

2007-01-01

227

Volcano Monitoring Using Google Earth  

NASA Astrophysics Data System (ADS)

At the Alaska Volcano Observatory (AVO), Google Earth is being used as a visualization tool for operational satellite monitoring of the region's volcanoes. Through the abilities of the Keyhole Markup Language (KML) utilized by Google Earth, different datasets have been integrated into this virtual globe browser. Examples include the ability to browse thermal satellite image overlays with dynamic control, to look for signs of volcanic activity. Webcams can also be viewed interactively through the Google Earth interface to confirm current activity. Other applications include monitoring the location and status of instrumentation; near real-time plotting of earthquake hypocenters; mapping of new volcanic deposits; and animated models of ash plumes within Google Earth, created by a combination of ash dispersion modeling and 3D visualization packages. The globe also provides an ideal interface for displaying near real-time information on detected thermal anomalies or "hotspot"; pixels in satellite images with elevated brightness temperatures relative to the background temperature. The Geophysical Institute at the University of Alaska collects AVHRR (Advanced Very High Resolution Radiometer) and MODIS (Moderate Resolution Imaging Spectroradiometer) through its own receiving station. The automated processing that follows includes application of algorithms that search for hotspots close to volcano location, flagging those that meet certain criteria. Further automated routines generate folders of KML placemarkers, which are linked to Google Earth through the network link function. Downloadable KML files have been created to provide links to various data products for different volcanoes and past eruptions, and to demonstrate examples of the monitoring tools developed. These KML files will be made accessible through a new website that will become publicly available in December 2006.

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

2006-12-01

228

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)

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.

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

2010-12-01

229

Volcano Monitoring Using Google Earth  

NASA Astrophysics Data System (ADS)

At the Alaska Volcano Observatory (AVO), remote sensing is an important component of its daily monitoring of volcanoes. AVO’s remote sensing group (AVORS) primarily utilizes three satellite datasets; Advanced Very High Resolution Radiometer (AVHRR) data, from the National Oceanic and Atmospheric Administration’s (NOAA) Polar Orbiting Satellites (POES), Moderate Resolution Imaging Spectroradiometer (MODIS) data from the National Aeronautics and Space Administration’s (NASA) Terra and Aqua satellites, and NOAA’s Geostationary Operational Environmental Satellites (GOES) data. AVHRR and MODIS data are collected by receiving stations operated by the Geographic Information Network of Alaska (GINA) at the University of Alaska’s Geophysical Institute. An additional AVHRR data feed is supplied by NOAA’s Gilmore Creek satellite tracking station. GOES data are provided by the Naval Research Laboratory (NRL), Monterey Bay. The ability to visualize these images and their derived products is critical for the timely analysis of the data. To this end, AVORS has developed javascript web interfaces that allow the user to view images and metadata. These work well for internal analysts to quickly access a given dataset, but they do not provide an integrated view of all the data. To do this AVORS has integrated its datasets with Keyhole Markup Language (KML) allowing them to be viewed by a number of virtual globes or other geobrowsers that support this code. Examples of AVORS’ use of KML include the ability to browse thermal satellite image overlays to look for signs of volcanic activity. Webcams can also be viewed interactively through KML to confirm current activity. Other applications include monitoring the location and status of instrumentation; near real-time plotting of earthquake hypocenters; mapping of new volcanic deposits using polygons; and animated models of ash plumes, created by a combination of ash dispersion modeling and 3D visualization packages.

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

2009-12-01

230

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

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).

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

2001-01-01

231

The geomorphology of an Aleutian volcano following a major eruption: The 7-8 August 2008 eruption of Kasatochi Volcano, Alaska, and its aftermath  

USGS Publications Warehouse

Analysis of satellite images of Kasatochi volcano and field studies in 2008 and 2009 have shown that within about one year of the 78 August 2008 eruption, significant geomorphic changes associated with surface and coastal erosion have occurred. Gully erosion has removed 300,000 to 600,000 m3 of mostly fine-grained volcanic sediment from the flanks of the volcano and much of this has reached the ocean. Sediment yield estimates from two representative drainage basins on the south and west flanks of the volcano, with drainage areas of 0.7 and 0.5 km2, are about 104 m3 km-2 yr-1 and are comparable to sediment yields documented at other volcanoes affected by recent eruptive activity. Estimates of the retreat of coastal cliffs also made from analysis of satellite images indicate average annual erosion rates of 80 to 140 m yr-1. If such rates persist it could take 35 years for wave erosion to reach the pre-eruption coastline, which was extended seaward about 400 m by the accumulation of erupted volcanic material. As of 13 September 2009, the date of the most recent satellite image of the island, the total volume of material eroded by wave action was about 106 m3. We did not investigate the distribution of volcanic sediment in the near shore ocean around Kasatochi Island, but it appears that erosion and sediment dispersal in the nearshore environment will be greatest during large storms when the combination of high waves and rainfall runoff are most likely to coincide. ?? 2010 Regents of the University of Colorado.

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

2010-01-01

232

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

USGS Publications Warehouse

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.

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

2007-01-01

233

Using Google Maps to Access USGS Volcano Hazards Information  

NASA Astrophysics Data System (ADS)

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.

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

2006-12-01

234

Volcanic Eruptions, Landscape Disturbance, and Potential Impacts to Marine and Terrestrial Ecosystems in Alaska: An Example from the August 2008 Eruption of Kasatochi Volcano  

NASA Astrophysics Data System (ADS)

The magnitude, style, and sometimes-prolonged nature of volcanic activity in Alaska has had significant impact on ecological habitat. The accumulation of volcaniclastic deposits during eruptions have destroyed or altered areas important to the success of various species and it may take years to decades for landforms and surfaces to recover and become habitable again. Kasatochi volcano, in the Aleutian Islands of Alaska, erupted explosively on August 7-8, 2008 and the rich nesting habitat for several species of seabirds on the island was completely destroyed. The eruption produced thick pyroclastic fall and flow deposits and several SO2 rich ash-gas plumes that reached 14 to 18 km above sea level. Pyroclastic deposits are several tens of meters thick, blanket the entire island, and initially extended seaward to increase the diameter of the island by about 800 m. Wave and gully erosion have modified these deposits and have exhumed some pre-eruption surfaces. Analysis of surface erosional features observed in satellite and time-lapse camera images and field studies have shown that by September 2009, gully erosion removed 300,000-600,000 m3 of mostly fine-grained volcanic sediment from the volcano flanks and much of this has reached the ocean. Sediment yield estimates from two representative drainage basins are about 104 m3km-2yr-1 and are comparable to sediment yields at other active volcanoes outside of Alaska. Coastal erosion rates at Kasatochi are as high as 80-140 myr-1 and parts of the northern coastline have already been eroded back to pre-eruption positions. As of March, 2011 about 72% of the material emplaced beyond the pre-eruption coastline on the northern sector of the island has been removed by wave erosion. Parts of the southern coastline have prograded beyond the post-eruption shoreline as a result of long-shore transport of sediment from north to south. As of March 2011, the total volume of material eroded by wave action was about 107 m3. The preferred nesting habitat for the estimated 500,000 seabirds (Crested and Least Auklets) are rocky crevices in boulder or talus fields. As long-lived species, Auklets are adapted to annual reproductive failure; however, given that less than 25 percent of preexisting nesting areas have been exhumed in the three years since the eruption the lack of suitable nesting habitat should lead to declines in Auklet populations. Ultimately, the exhumation rate of pre-existing nesting habitat or generation of new talus fields, will dictate Auklet population changes on and around Kasatochi Island. Volcanic eruptions as large or larger than the 2008 Kasatochi eruption are common in the geologic history of the Aleutian arc. Within the past several thousand years there have been many eruptions that produced >10 km3 of volcanic material that covered extensive areas of the Alaska Peninsula and some Aleutian Islands resulting in unknown ecological impacts. Study of the 2008 Kasatochi eruption is providing a much-needed opportunity to evaluate the biological and geological linkages that control habitat recovery following a severe natural disturbance.

Waythomas, C. F.; Drew, G. S.

2011-12-01

235

MTU Volcanoes Page  

NSDL National Science Digital Library

Michigan Technological University Volcanoes Page, which is sponsored by the Keweenaw Volcano Observatory, aims to provide information about volcanoes to the public and to complement other informational sites on the Web. Visitors will find information on what a volcano is, currently active volcanoes throughout the world, remote sensing of volcanoes, volcanic humor, and much more. The volcano hazard section of the site contains primarily original content that provides a Basic Guide to Volcanic Hazards and details Volcanic Cloud Hazards to Aviation, while offering volcano safety recommendations to the public. Although the site could use an update to its layout and organization, it does do a good job of presenting an interesting mix of unique information.

236

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

USGS Publications Warehouse

Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km south–southwest 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 (3×106 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.

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

2013-01-01

237

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

USGS Publications Warehouse

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.

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

238

Living With Volcanoes: The USGS Volcano Hazards Program  

NSDL National Science Digital Library

This report summarizes the Volcano Hazards Program of the United States Geological Survey (USGS). Topics include its goals and activities, some key accomplishments, and a plan for future operations. There are also discussions of active and potentially active volcanoes in the U.S., the role of the USGS volcano observatories, prediction of eruptions, and potential danger to aircraft from volcanic plumes.

239

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

USGS Publications Warehouse

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.

2013-01-01

240

Ground deformation associated with the precursory unrest and early phases of the January 2006 eruption of Augustine volcano, Alaska  

USGS Publications Warehouse

On January 11, 2006 Augustine Volcano erupted after nearly 20 years of quiescence. Global Positioning System (GPS) instrumentation at Augustine, consisting of six continuously recording, telemetered receivers, measured clear precursory deformation consistent with a source of inflation or pressurization beneath the volcano's summit at a depth of around sea level. Deformation began in early summer 2005, and was preceded by a subtle, but distinct, increase in seismicity, which began in May 2005. After remaining more or less constant, deformation rates accelerated on at least three stations beginning in late November 2005. After this date, GPS data suggest the upward propagation of a small dike into the edifice, which, based on the style of deformation and high levels of gas emission, appears to have ascended to shallow levels by mid-December 2005, about four weeks before the eruption began. Copyright 2006 by the American Geophysical Union.

Cervelli, P. F.; Fournier, T.; Freymueller, J.; Power, J. A.

2006-01-01

241

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)

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.

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

2011-12-01

242

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

USGS Publications Warehouse

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.

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

2002-01-01

243

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

USGS Publications Warehouse

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.

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

1996-01-01

244

Infrasound Studies of Alaskan Volcanoes  

NASA Astrophysics Data System (ADS)

Infrasound has been used to study a number of Alaskan volcanic eruptions over the last 15 years. Arrays include the I53US array of 8 sensors in Fairbanks installed in 2002 under the CTBT umbrella; an array of 4 sensors installed at Okmok Volcano in summer 2010 by the Alaska Volcano Observatory (AVO); and a 6-sensor array installed in Dillingham in September 2010 by the UAF Infrasound Group. Individual sensors have been installed by AVO at Pavlof (1996), Shishaldin (1997), Augustine (2006), Fourpeaked (2006), and Redoubt (2009) volcanoes. These have been especially valuable because they provide precise source timing and signal strength that allow the correct identification of atmospheric paths. Small volcanic explosions have been recorded at local stations only for Pavlof, Shishaldin and Fourpeaked volcanoes. The more interesting large explosive eruptions have been recorded on both local stations and arrays from eruptions at Augustine in 2006 (13 events), Fourpeaked in 2006 (2 events), Cleveland in 2007 (1 event), Okmok in 2008 (1 sustained event), Kasatochi in 2008 (5 events), and Redoubt in 2009 (over 30 events). Pressures up to 6 Pa have been recorded for the largest Redoubt event at a distance of 547 km from the array, and 1.2 Pa for the largest Kasatochi event at a distance of 2104 km. We determined reduced pressures (equivalent pressure at 1 km assuming 1/r decay) and find that Kasatochi exceeds 2500 Pa and Redoubt 1600 Pa. The smaller explosive eruptions at Augustine yield reduced pressures of 40 to 300 Pa. There is reasonable correlation between measured pressures and signal durations and the ash cloud heights and tephra volumes, hence the infrasound data are useful for hazard assessment. However, the long travel times (3 sec per km) suggest that infrasound array data arrive too late for primary detection but are good for estimating other attributes such as size. Infrasound data may also be combined with seismic data to determine the partitioning of energy into the atmosphere and ground, which varies as a function of depth and eruption style. The increased instrumentation coupled with the high rate of volcanic activity in Alaska has provided many significant research opportunities.

McNutt, S. R.; Arnoult, K.; Szuberla, C.; Olson, J. V.; Wilson, C. R.

2010-12-01

245

Mechanics and Timescales of Magma Mixing Inferred by Texture and Petrology of Basalt Inclusions and Host Andesite From the 2006 Eruption of Augustine Volcano, Alaska  

NASA Astrophysics Data System (ADS)

This study characterizes the texture, mineralogy and phenocryst disequilibrium textures in basaltic inclusions and host andesite lavas and scoria to advance our understanding of the mechanics and timescales of open system magma processes driving the 2006 eruption at Augustine Volcano, Alaska. Inclusions account for approximately 1 volume percent in all andesite lithologies emplaced during the explosive, continuous, and effusive eruption phases. In outcrop, quenched basaltic to andesite inclusions (51.3 to 57.3 weight percent SiO2) hosted by andesite lavas (59.1-62.6 weight percent SiO2) range in diameter from 1 cm to over 9 cm, are dark black and characterized by vesicular interiors, quenched and cuspate margins, and porphyritic texture. Inclusion mineralogy is dominated by phenocryst-sized plagioclase with lesser amounts of hornblende, clinopyroxene and olivine, as well as, microphenocrysts-sized plagioclase, hornblende, clinopryoxene, olivine, magnetite, ilmenite and apatite in a glassy, vesicular and acicular groundmass. Intrusion of a hotter, basaltic magma into a cooler silicic magma followed by inclusion formation through mingling processes is evidenced by (1) plagioclase crystal textures displaying (a) oscillatory zoned interiors surrounded by a dusty sieved layer and enclosed by clear, euhedral overgrowth rims, (b) coarsely-sieved interiors characterized by 0.01 mm -0.02 mm diameter melt inclusions and/or similarly sized inclusions of clinopyroxene, orthopryoxene, or hornblende, (2) Anorthite concentration profiles of engulfed host plagioclase crystals displaying contact with a basaltic magma, (3)Fe-Ti oxides from inclusions and low-silica andesite host recording core to rim temperatures ranging from 908°C to 1100°C, indicative of pre- and post- mixing temperatures, respectively, with oxygen fugacity approximately 2 log units above the nickel-nickel oxide buffer. The closest approximation of the basaltic end-member magma composition involved in magma mixing processes at Augustine Volcano and recorded in all 2006 erupted lithologies is represented by the most mafic inclusions, which consistently exhibit the greatest abundance of vesicles, fewest number of phenocryst sized plagioclase, largest volume of microlites, and highest temperatures of formation.

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

2010-12-01

246

Temporal-spatial variations of stress at Redoubt volcano, Alaska, inferred from inversion of fault plane solutions  

NASA Astrophysics Data System (ADS)

We inverted fault plane solutions (FPS) of 420 earthquakes, with a largest magnitude of 3.1, mostly occupying a 4×4×10-km 3 volume beneath Redoubt volcano, for principal stress directions during 1989-1998. On average, FPSs were computed with 8 P-wave readings, inversions performed with 48 FPS, yielding misfits of 7°, and the size of the 95% confidence regions of the stress directions is 30°. During the 1989-1990 eruptions stresses were typically: sub-horizontal ? 1 and ? 2 striking ESE-WNW and NNE-SSW, respectively, and near-vertical ? 3, whereas during July 1991-January 1998 we found: near-vertical ? 1, and sub-horizontal ? 2 and ? 3 striking SSE-NNW and ENE-WSW, respectively. We found differences in plunge of ? 1, up to 60°, between 1990 and 1991, and sub-volumes with different stress at the 99% confidence level, evaluated with the z-test. Based on the changes in stress directions from the eruptive to the inactive period, we infer that the magnitudes of principal stresses increased progressively during the eruptions and had subsequently decreased by the post-eruption period. The observations can be explained by expansion and contraction of a plexus-like magma body together with changes in physical properties of the magmas involved. We estimate that the absolute values of principal stresses are similar to each other and are in the range 182-187 Mpa.

Sánchez, John J.; Wyss, Max; McNutt, Stephen R.

2004-02-01

247

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

USGS Publications Warehouse

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.

Masterlark, T.; Lu, Z.; Rykhus, R.

2006-01-01

248

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

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.

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

2004-01-01

249

Dynamic deformation of Seguam Volcano, Alaska, 1992-2007, from multi-interferogram InSAR processing  

NASA Astrophysics Data System (ADS)

Seguam Volcano, located in the central Aleutian arc, homes two major calderas. All historical eruptions (1786-1790, 1827, 1891, 1892, 1901, 1927, 1977, and 1992-1993) are thought to have emanated from or near Pyre Peak, a volcanic cone located near the center of the western caldera. A time-series ERS-1/2 and ENVISAT radar interferometric synthetic aperture radar (InSAR) images were generated to study ground surface deformation during 1992-2008. The InSAR small baseline subset (SBAS) technique was applied to retrieve time-series deformation by reducing artifacts associated with baseline uncertainties and atmospheric delay anomalies. InSAR images from two adjacent tracks were independently process to validate results. In contrast to the steady subsidence at a rate of ~1.5 cm/yr over the western Seguam Island, the eastern caldera has experienced 4 episodes of deformation: ~1.5 cm/year subsidence during June 1993 and July 1999 (stage 1), ~2.5 cm/year inflation during July 1999 and November 2000 (stage 2), ~1.5 cm/year subsidence during November 2000 and July 2005 (stage 3), and ~2 cm/year inflation during July 2005 and 2007 (stage 4). Source models suggest a static subsidence source at less than 2 km deep over the western caldera. Models of the eastern caldera indicate that the inflation source is at 3-5 km depth while the subsidence source is less than 2 km deep. We suggest that basaltic magma pulses, which intermittently flow into a storage chamber residing at 3-5 km deep, drive inflation at eastern caldera. The injected magma degasses and the volatile products accumulate in a shallow poroelastic storage chamber, resulting deflation of the eastern caldera. The steady subsidence of over the western part of Seguam Island is probably driven by thermoelastic contraction of lava flows emplaced in 1992 and previous eruptions.

Lee, C.; Lu, Z.; Won, J.; Jung, H.; Dzurisin, D.

2010-12-01

250

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

SciTech Connect

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.

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

1986-05-01

251

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

USGS Publications Warehouse

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.

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

2004-01-01

252

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)

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.

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

2002-12-01

253

Magma mixing revealed by bulk-rock, phenocryst and microlite compositions in basaltic andesite samples from the 2008 eruption of Kasatochi Island volcano, central Aleutian Islands, Alaska  

NASA Astrophysics Data System (ADS)

The 7-8 August, 2008 eruption of Kasatochi Volcano, located in the central Aleutians Islands, Alaska, produced compositionally heterogeneous basaltic andesite (52-55 wt% SiO2). Bulk compositions of basaltic andesite samples lie along linear trends in element-element variation diagrams, while plagioclase, titanomagnetite and amphibole phenocrysts from the basaltic andesite are compositionally bimodal. Titanomagnetite phenocrysts are divided compositionally into low-Ti (~5 wt. % TiO2) and high-Ti (~8-10 wt. % TiO2) groups, while amphibole phenocrysts are divided into low-Al (~10-12 wt. % Al2O3) and high-Al (~14-16 wt. % Al2O3) populations. The first plagioclase population (Group 1), which is volumetrically dominant, consists of oscillatory-zoned phenocrysts that trend towards comparatively low-Ca rims (An55-65). These phenocrysts are normally zoned, with discrete spikes up to ~An90. The second population (Group 2) is more calcic with most rims up to ~An90, yet a subpopulation exists where rims sharply decrease in calcium content, reaching as low as ~An60, but are otherwise texturally and compositionally homogeneous (~An90). In addition to phenocryst compositions, plagioclase microlites are normally zoned, > 50% have rim compositions > An80, and they are typically more calcic than Group 1 rims. The most likely explanation for the compositional diversity in the bulk and phenocrysts is mixing between mafic and silicic end members, leading to linear mixing trends in the basaltic andesite bulk compositions. Group 1 plagioclase phenocrysts, low-Al amphibole and high-Ti titanomagnetite likely derived from the silicic mixing end member, while the mafic mixing end member contributed the Group 2 plagioclase phenocrysts, high-Al amphibole and low-Ti titanomagnetite. Plagioclase-liquid thermometry indicates that the mafic end member was likely hotter (900-1050 °C) than the silicic end member (800-950 °C). Microlites are frequently assumed to form due to decompression and magmatic degassing during ascent and eruption. However, in the case of Kasatochi, the mixing of these two magmas prior to eruption, and the temperature difference between them, led to undercooling of the mafic end member, and the nucleation of the anomalously high-An microlites in the mafic end member's more calcic liquids.

Neill, O. K.; Larsen, J. F.; Izbekov, P. E.; Nye, C. J.

2013-12-01

254

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

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.

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

1997-01-01

255

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

USGS Publications Warehouse

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.

Hoblitt, R. P.

1994-01-01

256

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

NASA Astrophysics Data System (ADS)

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.

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

2002-12-01

257

Earth Observatory: Ash Plume across the North Atlantic  

NSDL National Science Digital Library

This Earth Observatory image of the day shows the ash plume of Iceland's Eyjafjallajokull volcano spreading from Iceland to continental Europe. The page includes a short article on the volcano and its effect on European airspace.

2010-04-29

258

Super Volcano  

NSDL National Science Digital Library

Deep beneath the surface of Earth lies one of the most destructive and yet least understood of the natural forces on the planet: the super volcano. This radio broadcast presents discussions with scientists at Yellowstone National Park who are investigating this potentially devastating natural phenomenon. Yellowstone National Park is one of the largest supervolcanoes in the world. It last erupted 640,000 years ago and scientists are now predicting that the next eruption may not be far off. To discover more, a new volcanic observatory has been built in the park to monitor the extreme volcanic activity going on beneath the surface of this much visited destination. The broadcast is 30 minutes in length.

259

United States Geologic Survey: Selected Volcano Information  

NSDL National Science Digital Library

This United States Geological Survey (USGS) Volcano Hazards Program site contains links to selected material related to volcanic hazards. Users can access information about the volcanic hazards program, publications, topical maps of volcanoes world wide, aviation safety reports, volcanic hazard reports, computer software, volcano digital series and educational videos. Several USGS fact sheets are also available for volcanoes in Alaska, Arizona, California, Hawaii, the Pacific Northwest and around the world. Fact sheets can be downloaded as pdf files or html. This site contains a wide variety of comprehensive material on the world's volcanoes and the hazards associated with them.

2007-01-27

260

Aniakchak Crater, Alaska Peninsula  

USGS Publications Warehouse

The discovery of a gigantic crater northwest of Aniakchak Bay (see fig. 11) closes what had been thought to be a wide gap in the extensive series of volcanoes occurring at irregular intervals for nearly 600 miles along the axial line of the Alaska Peninsula and the Aleutian Islands. In this belt there are more active and recently active volcanoes than in all the rest of North America. Exclusive of those on the west side of Cook Inlet, which, however, belong to the same group, this belt contains at least 42 active or well-preserved volcanoes and about half as many mountains suspected or reported to be volcanoes. The locations of some of these mountains and the hot springs on the Alaska Peninsula and the Aleutian Islands are shown on a map prepared by G. A. Waring. Attention has been called to these volcanoes for nearly two centuries, but a record of their activity since the discovery of Alaska is far from being complete, and an adequate description of them as a group has never been written. Owing to their recent activity or unusual scenic beauty, some of the best known of the group are Mounts Katmai, Bogoslof, and Shishaldin, but there are many other beautiful and interesting cones and craters.

Smith, Walter R.

1925-01-01

261

Nicaraguan Volcanoes  

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 ...

2013-04-18

262

Pattern Recognition from Long Period Earthquake Swarms, Redoubt Volcano, AK  

NASA Astrophysics Data System (ADS)

Long-period earthquake swarms are common indicators of volcanic unrest and can be used to predict eruptions. However, not all earthquake swarms lead to an eruption but may die off instead. Variabilities in characteristics of swarms can false predict eruptions. During the 2009 eruption of Redoubt Volcano in Alaska, there were five long-period earthquake swarms, three of which preceded explosive eruptions and two that did not. These data were used to find the variable characteristics that could determine whether or not an eruption is imminent. Data were recorded by the Alaska Volcano Observatory throughout the eruption. Band-pass filtering removed unwanted frequencies outside the long-period earthquake range of about 0.5-5.0 Hz. The onset of long-period earthquakes were cataloged and used to find features that varied between swarms. Duration times of individual events were calculated using the Arias Intensity. The power spectrum of the autocorrelation was used to determine central frequencies and shape factor values for each swarm. Earthquake swarms that preceded eruptions had shorter duration times, higher central frequencies, and lower shape factor values than swarms that did not precede eruptions. Features that did not change based on eruption outcome included the time between events and the peak frequency from a low-order autocorrelation power spectrum.

Carlisle, C.

2012-12-01

263

Three-dimensional seismic velocity structure and earthquake relocations at Katmai, Alaska  

NASA Astrophysics Data System (ADS)

We invert arrival time data from local earthquakes occurring between September 2004 and May 2009 to determine the three-dimensional (3D) upper crustal seismic structure in the Katmai volcanic region. Waveforms for the study come from the Alaska Volcano Observatory's permanent network of 20 seismic stations in the area (predominantly single-component, short period instruments) plus a densely spaced temporary array of 11 broadband, 3-component stations. The absolute and relative arrival times are used in a double-difference seismic tomography inversion to solve for 3D P- and S-wave velocity models for an area encompassing the main volcanic centers.

Murphy, Rachel; Thurber, Clifford; Prejean, Stephanie; Bennington, Ninfa

2014-04-01

264

Reunion Island Volcano Erupts  

NASA Technical Reports Server (NTRS)

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

2002-01-01

265

Alaska Museum of Natural History  

NSDL National Science Digital Library

Ever wanted to have your own volcano laboratory, but didn't want to clean up all that lava? Be a super-scientist and create your own volcano online. The Alaska Museum of Natural History is dedicated to the study and exhibition of Alaskaâs natural history and to promoting and developing educational programs which benefit students and enrich the curricula of schools and universities. The Museum focuses on Alaska's unique geological, cultural, and ecological history. In addition to Make Your Own Volcano, the website offers extensive links, resources and educational modules including Kids Activity Sheets, Dinosaurs of Alaska, the Broken Mammoth Archeological Site, and Dinosaur Tracks, which explores the information that can be gleaned from the study of footprints.

266

Ground surface deformation patterns, magma supply, and magma storage at Okmok volcano, Alaska, from InSAR analysis: 2. Coeruptive deflation, July–August 2008  

Microsoft Academic Search

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

Zhong Lu; Daniel Dzurisin

2010-01-01

267

Alaska Seismic Network Upgrade and Expansion  

NASA Astrophysics Data System (ADS)

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.

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

2009-12-01

268

Variability of sulfate aerosol concentrations at Mauna Loa observatory, Hawaii  

NASA Astrophysics Data System (ADS)

Daily total particulate matter observations of sulfate, sodium, and methanesulfonate were collected at Mauna Loa Observatory (19.54°N, 155.57°W, 3397m ASL) during 1995-2008. Observations were restricted to nighttime, downslope conditions and were thus representative of free tropospheric air masses. In this paper we focus analyses on 2008, when active volcanoes in Hawaii, Alaska, Indonesia, and elsewhere may have perturbed the northern hemisphere sulfur budget. The 2008 seasonal cycle of aerosol species was broadly consistent with the 1995-2008 mean, although the springtime peaks of anthropogenically-derived sulfate were larger than typical. Trajectories originated from East Asia less frequently and from North America more frequently in spring 2008 than in the long term data record, possibly linked to the strong La Nin~a conditions that year.

Potter, Lauren; Kreidenweis, Sonia; Huebert, Barry; Howell, Steven; Zhuang, John; Morman, Molly

2013-05-01

269

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

SciTech Connect

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.

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

270

Magnetotelluric Investigations of the Kilauea Volcano, Hawaii  

Microsoft Academic Search

A collaborative effort between Lawrence Berkeley National Laboratory, Sandia National Laboratories, Electromagnetic Instruments and the USGS Hawaiian Volcano Observatory has undertaken a three-dimensional (3D) magnetotelluric (MT) study of the Kilauea volcano in Hawaii. The survey objectives are 1): to produce a high quality 3D MT data set over the central caldera and the eastern and southwestern rift zones, 2) to

G. Hoversten; G. A. Newman; E. Gasperikova; J. P. Kauahikaua

2002-01-01

271

Volcano-tectonic deformation at Mount Shasta and Medicine Lake volcanoes, northern California, from GPS: 1996-2004  

Microsoft Academic Search

Mount Shasta and Medicine Lake volcanoes are two of the three Cascade volcanoes targeted for dense GPS and strainmeter deployments by the magmatic systems component of Earthscope's Plate Boundary Observatory (PBO). Leveling surveys indicate an average subsidence rate of ˜9 mm\\/yr at Medicine Lake volcano since at least 1954, which could result from draining of a magma reservoir, cooling\\/crystallization of

M. Lisowski; M. Poland; D. Dzurisin; S. Owen

2004-01-01

272

Volcanoes Online  

NSDL National Science Digital Library

This Thinkquest offers an encyclopedic look at plate tectonics and volcanoes. Reference sections describe the interior of the Earth, continental drift, sea floor spreading, subduction, volcano types and eruptions, lava flow, and famous volcanoes. Lesson plans cover the internal structure of Earth, plate tectonic theory, and how volcanic eruptions and earthquakes affect the human environment. There is a plasticine plates activity; a volcano-related game, crossword puzzle, and comics section; and a volcanic database containing descriptions and photographs of volcanoes around the world.

273

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

USGS Publications Warehouse

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.

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

2011-01-01

274

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

USGS Publications Warehouse

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.

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

2010-01-01

275

GlobVolcano: Earth Observation Services for global monitoring of active volcanoes  

Microsoft Academic Search

The GlobVolcano project 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 Volcanological Observatories and other mandate users (Civil Protection, scientific communities of volcanoes) in their monitoring activities. The information service is assessed in close cooperation with the

L. Tampellini; R. Ratti; S. Borgström; F. M. Seifert; G. Solaro

2009-01-01

276

Computer Communications With Mauna Loa Solar Observatory.  

National Technical Information Service (NTIS)

The High Altitude Observatory, a division of the National Center for Atmospheric Research, has operated the Mauna Loa Solar Observatory (MLSO) from a site on the volcano, Mauna Loa, Hawaii, since 1965. In the Spring of 1983, the staff of MLSO was asked by...

G. Garcia P. Seagraves

1983-01-01

277

Virtual Volcano  

NSDL National Science Digital Library

The Discovery Channel's website has several interactive features on volcanoes to complement its programs on Pompeii. At the homepage, visitors can explore a virtual volcano, by clicking on "Enter". The virtual volcano has several components. The first is a quickly revolving globe with red triangles and gray lines on it that represent active volcanoes and plate boundaries. Clicking on "Stop Rotation", located next to the globe, will enable a better look. Visitors can also click one of the topics below the globe, to see illustrations of "Tectonic Plates", "Ring of Fire" (no, not the Johnny Cash song), and "Layers Within". Visitors can click on "Build your Own Volcano and Watch it Erupt" on the menu on the left side of the page, where they will be given a brief explanation of two factors that affect the shape and explosiveness of volcanoes: viscosity and gas. Then they must choose, and set, the conditions of their volcano by using the arrows under the viscosity and gas headings, and clicking on "Set Conditions", underneath the arrows. Once done, a description of the type of volcano created will be given, and it's time to "Start Eruption". While the lava flows, and the noise of an eruption sounds, terms describing various features of the volcano are superimposed on the virtual volcano, and can be clicked on for explanations.

278

Digital Data for Volcano Hazards at Newberry Volcano, Oregon  

USGS Publications Warehouse

Newberry volcano is a broad shield volcano located in central Oregon, the product of thousands of eruptions, beginning about 600,000 years ago. At least 25 vents on the flanks and summit have been active during the past 10,000 years. The most recent eruption 1,300 years ago produced the Big Obsidian Flow. Thus, the volcano's long history and recent activity indicate that Newberry will erupt in the future. Newberry Crater, a volcanic depression or caldera has been the focus of Newberry's volcanic activity for at least the past 10,000 years. Newberry National Volcanic Monument, which is managed by the U.S. Forest Service, includes the caldera and extends to the Deschutes River. Newberry volcano is quiet. Local earthquake activity (seismicity) has been trifling throughout historic time. Subterranean heat is still present, as indicated by hot springs in the caldera and high temperatures encountered during exploratory drilling for geothermal energy. The report USGS Open-File Report 97-513 (Sherrod and others, 1997) describes the kinds of hazardous geologic events that might occur in the future at Newberry volcano. A hazard-zonation map is included to show the areas that will most likely be affected by renewed eruptions. When Newberry volcano becomes restless, the eruptive scenarios described herein can inform planners, emergency response personnel, and citizens about the kinds and sizes of events to expect. The geographic information system (GIS) volcano hazard data layers used to produce the Newberry volcano hazard map in USGS Open-File Report 97-513 are included in this data set. Scientists at the USGS Cascades Volcano Observatory created a GIS data layer to depict zones subject to the effects of an explosive pyroclastic eruption (tephra fallout, pyroclastic flows, and ballistics), lava flows, volcanic gasses, and lahars/floods in Paulina Creek. A separate GIS data layer depicts drill holes on the flanks of Newberry Volcano that were used to estimate the probability of coverage by future lava flows.

Schilling, S. P.; Doelger, S.; Sherrod, D. R.; Mastin, L. G.; Scott, W. E.

2008-01-01

279

Erupting Volcanoes!  

NSDL National Science Digital Library

This lesson presents volcanoes through the making of volcano models. While students are constructing their physical representations of volcanoes, they will be filled with questions about volcanoes as well as how to build their models. This process will provide students with a tangible reference for learning about volcanoes and give them a chance to problem-solve as they build their models. Students will be able to observe how the eruption changes the original form of their volcano model. In this way, students see first hand how this type of phenomenon creates physical change. While students at this level may struggle to understand larger and more abstract geographical concepts, they will work directly with material that will help them build a foundation for understanding concepts of phenomena that sculpt the Earth.

280

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

NASA Astrophysics Data System (ADS)

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.

Swenson, R.; Nye, C. J.

2009-12-01

281

Character, mass, distribution, and origin of tephra-fall deposits from the 2009 eruption of Redoubt Volcano, Alaska—Highlighting the significance of particle aggregation  

NASA Astrophysics Data System (ADS)

The 2009 eruption of Redoubt Volcano included 20 tephra-producing explosions between March 15, 2009 and April 4, 2009 (UTC). Next-Generation radar (NEXRAD) data show that plumes reached heights between 4.6 km and 19 km asl and were distributed downwind along nearly all azimuths of the volcano. Explosions lasted between < 1 and 31 min based on the signal duration at a distal seismic station (86 km). From Moderate Resolution Imaging Spectroradiometer (MODIS) imagery and field data, we estimate that over 80,000 km2 received at least minor ash fall (> 0.8 mm thick), including communities along the Kenai Peninsula (80-100 km) and the city of Anchorage (170 km). Trace ash (< 0.8 mm) was reported as far as Fairbanks, 550 km NNE of the volcano. We estimate the total mass of tephra-fall deposits at 54.6 × 109 kg with a total DRE volume of 20.6 × 106 m3. On March 15, a small (4.6 km asl) phreatic explosion containing minor, non-juvenile ash, erupted through the summit ice cap. The first five magmatic explosions (events 1-5) occurred within a 6-hour period on March 23. Plumes rose to heights between 5.5 km and 14.9 km asl during 2- to 20-minute-duration explosions, and were dispersed mainly along a NNE trajectory. Trace ash fall was reported as far as Fairbanks. Owing to a shift in wind direction and heavy snowfall during these events, field discrimination among many of these layers was possible. All deposits comprise a volumetrically significant amount of particle aggregates, yet only event 5 deposits contain coarse clasts including glacier ice. The most voluminous tephra fall was deposited on March 24 (event 6) from a 15 minute explosion that sent a plume to 18.3 km asl, and dispersed tephra to the WNW. Within 10 km of the vent, this deposit contains 1-11 cm pumice clasts in a matrix of 1-2 mm aggregate lapilli. A small dome was presumably emplaced between March 23 and March 26 and was subsequently destroyed during 1-14 minute magmatic explosions of events 7-8 (March 26) that sent plumes between 8.2 km and 19 km asl. Ash fell along a broad swath to the ESE, covering communities along the Kenai Peninsula with up to 1 mm of ash. Proximal deposits are largely composed of aggregate lapilli of 1-2 mm with very little coarse juvenile material. Events 9-18 (March 27) sent plumes between 5.2 km and 15.5 km asl during < 1-11-minute-long explosions. Ash clouds dispersed along trajectories to the NE, ENE and N and event 17 deposited up to 1 mm of ash on upper Kenai Peninsula and Anchorage. A moderate-size dome was emplaced between March 29 and April 4 and was subsequently destroyed during event 19 on April 4 which lasted 31 min and sent ash to 15.2 km asl. The proximal deposit is principally composed of dense dome rock, unlike earlier events, indicating that event 19 was likely caused by dome failure. The cloud dispersed to the SE along a narrow trajectory and up to 1-2 mm of ash fell on the lower Kenai Peninsula. Particle size data showing a preponderance of fine ash, even in the most proximal locations, along with the abundance of aggregate lapilli documented in most samples, confirms that particle aggregation played a significant role in the 2009 eruption and induced premature fallout of fine ash.

Wallace, Kristi L.; Schaefer, Janet R.; Coombs, Michelle L.

2013-06-01

282

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

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.

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

1994-01-01

283

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

NASA Astrophysics Data System (ADS)

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.

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

1994-08-01

284

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)

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.

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

2010-12-01

285

2003 Eruption of Chikurachki Volcano, Paramushir Island, Northern Kuriles, Russia  

NASA Astrophysics Data System (ADS)

Chikurachki Volcano in the northern Kurile Islands erupted for the second time in two years in mid-April 2003. Although the Kamchatka Volcanic Eruptions Response Team (KVERT) received word of a possible eruption from residents of Paramushir Island on April 17, poor weather precluded confirmation of volcanic activity, and the exact start date is uncertain. On April 18, during routine satellite image analysis, the Alaska Volcano Observatory (AVO) detected an ash cloud from Chikurachki in GMS data and immediately notified the Federal Aviation Administration (FAA), National Weather Service, and other agencies. Subsequent formal alerts were issued through aviation and meteorological channels as outlined in the Alaska Interagency Operating Plan for Volcanic Ash Episodes. Thermal infrared imagery and trajectory models suggested the initial cloud was relatively low-level (below 25,000 ft ASL), however this height was not well constrained. Over the next several months, activity at Chikurachki consisted largely of strombolian bursts producing intermittent ash clouds reaching heights of generally less than 10-13,000 ft. ASL. Ash fall was noted as far as 60 km downwind. The last confirmed eruptive activity was June 16, 2003. During the eruption, AVHRR, MODIS, and GMS satellites captured images of the ash cloud as far as 300 km generally east and southeast of the volcano in the region heavily traveled North Pacific air routes. The propagation of volcanic clouds was monitored using visual and infrared channels and included a routine split-window analysis. Weak thermal anomalies were detected in AVHRR images suggesting minimal effusive activity near the central vent. Over the course of the eruption, aviation and meteorological authorities in Russia, the U.S., and Japan issued official notices regarding the eruption and the position and estimated height of the ash plume. Impacts to aviation were minor due to the low-level and intermittent nature of the eruption. Chikurachki is a young, basaltic 1816-m-tall stratovolcano on the northern coast of Paramushir Island, 370 km southwest of Petropavlovsk-Kamchatsky. No seismic or other instrumentation exists near the volcano, however satellite imagery is examined at least twice daily to look for evidence of volcanic unrest. The nearest community is Severo-Kurilsk (population ~3,000), 60 km to the northeast. Previous historical eruptions have primarily consisted of VEI 1-2 strombolian eruptions, however, plinian eruptions with significant local fall deposits were recorded in 1986 and 1853. Its most recent eruption from January 25 - March 16, 2002 was similar in character to the 2003 event.

Schneider, D. J.; Girina, O. A.; Neal, C. A.; Kotenko, L.; Terentiev, N. S.; Izbekov, P.; Belousov, I.; Senyukov, S.; Ovsyannikov, A. A.

2003-12-01

286

Ground surface deformation patterns, magma supply, and magma storage at Okmok volcano, Alaska, from InSAR analysis: 2. Coeruptive deflation, July-August 2008  

NASA Astrophysics Data System (ADS)

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.

Lu, Zhong; Dzurisin, Daniel

2010-05-01

287

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

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.

Lu, Zhong; Dzurisin, Daniel

2010-01-01

288

The recent warming of permafrost in Alaska  

Microsoft Academic Search

This paper reports results of an experiment initiated in 1977 to determine the effects of climate on permafrost in Alaska. Permafrost observatories with boreholes were established along a north–south transect of Alaska in undisturbed permafrost terrain. The analysis and interpretation of annual temperature measurements in the boreholes and daily temperature measurements of the air, ground and permafrost surfaces made with

T. E. Osterkamp

2005-01-01

289

Volcano Activity  

NSDL National Science Digital Library

Part of Prentice Hall's Planet Diary, this computer activity covers volcanic activity. Students research the most recent volcanic activity and the locations and names of each volcano. They then find out which tectonic plates the volcanoes are located on or if they are hot spots, and if any are part of the Ring of Fire.

290

Evaluation of gases, condensates, and SO2 emissions from Augustine volcano, Alaska: the degassing of a Cl-rich volcanic system  

USGS Publications Warehouse

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.

Symonds, R. B.; Rose, W. I.; Gerlach, T. M.; Briggs, P. H.; Harmon, R. S.

1990-01-01

291

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

USGS Publications Warehouse

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 cm2 and the largest event has a reduced displacement of 589 cm2 (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.

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

2004-01-01

292

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

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.

Schaefer, J. R.; Scott, W. E.; Evans, W. C.; Jorgenson, J.; McGimsey, R. G.; Wang, B.

2008-01-01

293

Active Monitoring for Active Volcanoes - A challenge at Sakurajima volcano  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

294

Model Volcanoes  

NSDL National Science Digital Library

In this lesson, students will explore volcanoes by constructing models and reflect upon their learning through drawing sketches of their models. Once they have finished making their models, they will experiment with making their volcanoes erupt. They will observe how eruption changes the original form of their volcano models. In this way, students see first hand how this type of phenomena creates physical change. While students at this level may struggle to understand larger and more abstract geographical concepts, they will work directly with material that will help them build a foundation for understanding concepts of phenomena that sculpt the earth.

295

Understanding Volcanoes  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades K-5. It focuses on plate tectonics and volcanoes acting as a cooling vent for the inner core of the Earth. Students build model volcanoes and use them as comparisons for actual volcanoes. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

Hoffman, Dianne

296

WIYN Observatory  

NASA Astrophysics Data System (ADS)

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...

Murdin, P.

2000-11-01

297

Cascade Volcanoes  

USGS Multimedia Gallery

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....

2009-12-08

298

Observation of volcanoes through webcams: Tools and techniques  

NASA Astrophysics Data System (ADS)

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.

Lovick, J.; Lawlor, O.; Dean, K.; Dehn, J.

2008-12-01

299

Volcano Infrasound  

NASA Astrophysics Data System (ADS)

Open-vent volcanoes generate prodigious low frequency sound waves that tend to peak in the infrasound (<20 Hz) band. These long wavelength (> ~20 m) atmospheric pressure waves often propagate long distances with low intrinsic attenuation and can be well recorded with a variety of low frequency sensitive microphones. Infrasound records may be used to remotely monitor eruptions, identify active vents or track gravity-driven flows, and/or characterize source processes. Such studies provide information vital for both scientific study and volcano monitoring efforts. This presentation proposes to summarize and standardize some of the terminology used in the still young, yet rapidly growing field of volcano infrasound. Herein we suggest classification of typical infrasound waveform types, which include bimodal pulses, blast (or N-) waves, and a variety of infrasonic tremors (including broadband, harmonic, and monotonic signals). We summarize various metrics, including reduced pressure, intensity, power, and energy, in which infrasound excess pressures are often quantified. We also describe the spectrum of source types and radiation patterns, which are typically responsible for recorded infrasound. Finally we summarize the variety of propagation paths that are common for volcano infrasound radiating to local (<10 km), regional (out to several hundred kilometers), and global distances. The effort to establish common terminology requires community feedback, but is now timely as volcano infrasound studies proliferate and infrasound becomes a standard component of volcano monitoring.

Johnson, J. B.; Fee, D.; Matoza, R. S.

2013-12-01

300

Earthquakes at Loihi Submarine Volcano and the Hawaiian Hot Spot  

Microsoft Academic Search

Loihi is an active submarine volcano located 35 km south of the island of Hawaii and may eventually grow to be the next and southernmost island in the Hawaiian chain. The Hawaiian Volcano Observatory recorded two major earthquake swarms located there in 1971-1972 and 1975 which were probably associated with submarine eruptions or intrusions. The swarms were located very close

Fred W. Klein

1982-01-01

301

Earthquakes at Loihi submarine volcano and the Hawaiian hot spot  

Microsoft Academic Search

Loihi is an active submarine volcano located 35 km south of the island of Hawaii and may eventually grow to be the next and southernmost island in the Hawaiian chain. The Hawaiian Volcano Observatory recorded two major earthquake swarms located there in 1971-1972 and 1975 which were probably associated with submarine eruptions or intrusions. The swarms were located very close

Fred W. Klein

1982-01-01

302

Natural Resources Canada: Volcanoes of Canada  

NSDL National Science Digital Library

Natural Resources Canada has launched yet another impressive and educational Web site. At this site you can learn all you wanted to know about Canadian volcanoes and volcanology. The site offers an introduction to volcanoes, in-depth sections on types, eruptions, hazards, and risks. You can also discover interesting facts, such as how eruptions in Alaska and the Western coast of the US impact agriculture and air travel in Canada. In addition to text, the site offers a wonderful interactive Map of Canadian Volcanoes. The Catalogue of Canadian Volcanoes is also an excellent reference tool. Available in English and French, this site is easy to understand and ideal for science students as well as anyone interested in volcanology. This site is also reviewed in the August 22, 2003 NSDL Physical Sciences Report.

303

Spreading Volcanoes  

NASA Astrophysics Data System (ADS)

As volcanoes grow, they become ever heavier. Unlike mountains exhumed by erosion of rocks that generally were lithified at depth, volcanoes typically are built of poorly consolidated rocks that may be further weakened by hydrothermal alteration. The substrates upon which volcanoes rest, moreover, are often sediments lithified by no more than the weight of the volcanic overburden. It is not surprising, therefore, that volcanic deformation includes-and in the long term is often dominated by-spreading motions that translate subsidence near volcanic summits to outward horizontal displacements around the flanks and peripheries. We review examples of volcanic spreading and go on to derive approximate expressions for the time volcanoes require to deform by spreading on weak substrates. We also demonstrate that shear stresses that drive low-angle thrust faulting from beneath volcanic constructs have maxima at volcanic peripheries, just where such faults are seen to emerge. Finally, we establish a theoretical basis for experimentally derived scalings that delineate volcanoes that spread from those that do not.

Borgia, Andrea; Delaney, Paul T.; Denlinger, Roger P.

304

MDM Observatory  

NASA Astrophysics Data System (ADS)

MDM Observatory was founded by the University of Michigan, Dartmouth College and the Massachusetts Institute of Technology. Current operating partners include Michigan, Dartmouth, MIT, Ohio State University and Columbia University. The observatory is located on the southwest ridge of the KITT PEAK NATIONAL OBSERVATORY near Tucson, Arizona. It operates the 2.4 m Hiltner Telescope and the 1.3 m McG...

Murdin, P.

2000-11-01

305

GeoFORCE Alaska, A Successful Summer Exploring Alaska's Geology  

NASA Astrophysics Data System (ADS)

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.

Wartes, D.

2012-12-01

306

Volcano Baseball  

NSDL National Science Digital Library

In this game, learners are volcanoes that must complete several steps to erupt. Starting at home plate, learners draw cards until they have enough points to move to first base. This process repeats for each learner at each base, and each base demonstrates a different process in a volcano's eruption. The first learner to make it back to home plate erupts and is the winner. This is a good introduction to volcanoes. When learners set up a free account at Kinetic City, they can answer bonus questions at the end of the activity as a quick assessment. As a larger assessment, learners can complete the Smart Attack game after they've completed several activities.

Science, American A.

2009-01-01

307

GlobVolcano pre-operational services for global monitoring active volcanoes  

Microsoft Academic Search

The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate users (e.g. Civil Protection) in their monitoring activities. The information services are assessed in close cooperation with the user organizations for different types

Lucia Tampellini; Raffaella Ratti; Sven Borgström; Frank Martin Seifert; Aline Peltier; Edouard Kaminski; Marco Bianchi; Wendy Branson; Fabrizio Ferrucci; Barbara Hirn; Paul van der Voet; J. van Geffen

2010-01-01

308

Syrian Volcano  

NASA Technical Reports Server (NTRS)

23 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small volcano in the Syria Planum region of Mars. Today, the lava flows that compose this small volcano are nearly hidden by a mantle of rough-textured, perhaps somewhat cemented, dust. The light-toned streaks that cross the scene were formed by passing dust devils, a common occurrence in Syria.

Location near: 13.0oS, 102.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Autumn

2006-01-01

309

Volcanoes: Local Hazard, Global Issue  

NSDL National Science Digital Library

In this module, students can explore two ways that volcanoes affect Earth: by directly threatening people and the environments adjacent to them, and by ejecting aerosols into the atmosphere. The module consists of three investigations in which they will study the local effects of volcanism using images of Mount St. Helens, examine how the effects of volcanic activity can be remotely sensed and monitored from space using NASA data for Mount Spurr in Alaska, and see how geography and spatial perspective are useful in addressing global issues in the tracking and mapping of aerosol hazards such as the ash cloud emitted by the 1989 eruption on Redoubt Volcano. Each investigation is complete with overview, a list of materials and supplies, content preview, classroom procedures, worksheets, background, and evaluation.

310

Amateur Observatories  

NASA Astrophysics Data System (ADS)

A roundup of amateur observatories in this country and abroad, with construction and location details, concluding with a detailed description and architect's drawing of the author's own observatory at Worcester Park, Surrey. The text of the 1996 Presidential Address to the British Astronomical Association.

Gavin, M.

1997-08-01

311

Astronomical observatories  

NASA Technical Reports Server (NTRS)

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.

Ponomarev, D. N.

1983-01-01

312

New insights into Kilauea's volcano dynamics brought by large-scale relative relocation of microearthquakes  

Microsoft Academic Search

We investigated the microseismicity recorded in an active volcano to infer information concerning the volcano structure and long-term dynamics, by using relative relocations and focal mechanisms of microearthquakes. There were 32,000 earthquakes of the Mauna Loa and Kilauea volcanoes recorded by more than eight stations of the Hawaiian Volcano Observatory seismic network between 1988 and 1999. We studied 17,000 of

Jean-Luc Got; Paul Okubo

2003-01-01

313

Klyuchevskaya Volcano  

NASA Technical Reports Server (NTRS)

The Klyuchevskaya Volcano on Russia's Kamchatka Peninsula continued its ongoing activity by releasing another plume on May 24, 2007. The same day, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image, at 01:00 UTC. In this image, a hotspot marks the volcano's summit. Outlined in red, the hotspot indicates where MODIS detected unusually warm surface temperatures. Blowing southward from the summit is the plume, which casts its shadow on the clouds below. Near the summit, the plume appears gray, and it lightens toward the south. With an altitude of 4,835 meters (15,863 feet), Klyuchevskaya (sometimes spelled Klyuchevskoy or Kliuchevskoi) is both the highest and most active volcano on the Kamchatka Peninsula. As part of the Pacific 'Ring of Fire,' the peninsula experiences regular seismic activity as the Pacific Plate slides below other tectonic plates in the Earth's crust. Klyuchevskaya is estimated to have experienced more than 100 flank eruptions in the past 3,000 years. Since its formation 6,000 years ago, the volcano has seen few periods of inactivity. NASA image courtesy the MODIS Rapid Response Team at NASA GSFC. The Rapid Response Team provides daily images of this region.

2007-01-01

314

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

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.

Doukas, Michael P.

1995-01-01

315

Internet Geography: Volcanoes  

NSDL National Science Digital Library

This site is part of GeoNet Internet Geography, a resource for pre-collegiate British geography students and their instructors. This page focuses on various aspects of volcanoes, including the main features of a volcano, types of volcanoes, the Ring of Fire, locations of volcanoes, volcanic flows, and case studies about specific volcanoes.

316

Neutrino Observatories  

NSDL National Science Digital Library

This online article, from Cosmic Horizons: Astronomy at the Cutting Edge, takes an in-depth look at the new generation of astronomy equipment. It provides an overview of the discovery of neutrinos, subatomic particles, and their role in the developing field of physics, studies that showed that nuclear reactions, including those that power the stars, produce an enormous number of neutrinos, the creation of neutrino observatories deep underground and the stunning and unexpected advances these observatories have already made.

317

Alaska: A Bird's Eye View  

NSDL National Science Digital Library

This web based story tells of Tutangiaq (nicknamed 2T), a Canada Goose, who flies across the remote state of Alaska looking for his family. As he flies, he tells children about this fascinating 49th state of the US. Children learn how Alaska was purchased from the Russians, and other amazing facts about the state. They compare Alaska to other states that they may be living in or visiting. 2T takes a flight across volcanic chains in Alaska and tells the children how scientists monitor volcanoes from satellite images in near-real time and send warning signals to the aviation industry when they suspect or detect volcanic eruptions. At the coast, the bird also meets his walrus friend who tells him how global warming has caused the sea ice edge to recede and how this is adversely affecting marine life. Finally, 2T arrives in Fairbanks, the golden heart city of Alaska, where the children use satellite imagery to help him find and unite with his family.

2003-08-31

318

Volcano Deformation and Gravity Workshop Synopsis and Outcomes  

NASA Astrophysics Data System (ADS)

The 2008 Volcano Deformation and Temporal Gravity Change Workshop; Vancouver, Washington, 13-15 May 2008; A volcano workshop was held in Washington State, near the U.S. Geological Survey (USGS) Cascades Volcano Observatory. The workshop, hosted by the USGS Volcano Hazards Program (VHP), included more than 40 participants from the United States, the European Union, and Canada. Goals were to promote (1) collaboration among scientists working on active volcanoes and (2) development of new tools for studying volcano deformation. The workshop focused on conventional and emerging techniques, including the Global Positioning System (GPS), borehole strain, interferometric synthetic aperture radar (InSAR), gravity, and electromagnetic imaging, and on the roles of aqueous and magmatic fluids.

Dzurisin, Daniel; Lu, Zhong

2009-01-01

319

Establishment, test and evaluation of a prototype volcano surveillance system  

NASA Technical Reports Server (NTRS)

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.

Ward, P. L.; Eaton, J. P.; Endo, E.; Harlow, D.; Marquez, D.; Allen, R.

1973-01-01

320

Rainwater Observatory  

NSDL National Science Digital Library

The Rainwater Observatory, located in French Camp, Mississippi, features astronomy workshops for educators and educational programs for the public. It also hosts an informal astronomical association and an annual amateur astronomers' conference. The educator workshops focus on activities to teach astronomy using robotic telescopes available through the Las Cumbres Global Telescope Network (including the Sangre Telescope at Rainwater Observatory), and on learning hands-on activities that can be used in the classroom to teach concepts of astronomy. The Observatory's web site includes an ask-an-astronomer feature, a virtual tour, information on the Sangre Astronomical Research Telescope (their newest research telescope), and an e-newsletter with information about upcoming programs and events and current headlines in space science.

321

Explosive eruptions at Bezymianny Volcano (Kamchatka, Russia) from 2000-2009: warning system, prediction and risk assessment  

NASA Astrophysics Data System (ADS)

Explosive eruptions are the most hazardous volcanic events for aviation and for local population centers, and thus the prediction of such events is very important. Bezymianny Volcano (55° 58' N, 160° 35' E, height ~2869 m) has produced one to two explosive eruptions per year (VEI=2-3) since its most recent catastrophic eruption on March 30, 1956, which followed 900-1000 years of quiescence. Ash plumes from these eruptions rise to altitude of 6 to 15 km. KBGS began monitoring the activity of Kamchatkan volcanoes in 2000 using real-time seismic, visual (or video), and satellite (NOAA, AVHRR) data. Since February 2000, KBGS has used a warning system (http://www.emsd.ru/~ssl/monitoring/main.htm), which is based primarily on seismicity. All seismic activity is divided into two clusters: “at background” (normal) and “above background” (heightened) levels. Normal seismicity corresponds to the quiet state of the volcano. Heightened seismic activity accompanies an explosive eruption or indicates that it is possible. Seven eruptions of Bezymianny volcano were recorded and investigated from February 2000 to February 2004. The KBGS warning system detected increased seismic activity before five of these seven eruptions in near real time. In May 2004, the level of normal seismicity was adjusted and the first version of the prediction algorithm for Bezymianny eruptions was established. This algorithm was based on the typical eruption scenario (a sequence of precursors and its quantitative parameters) and was developed as a formalized scheme of decision-making about the possibility of eruption according to near real time seismic and satellite data. During 2004-2009, the staff of the Research Laboratory of Seismic and Volcanic Activity of KBGS successfully predicted eight of nine eruptions within 1-7 days prior to the start of eruption using this algorithm. The documents, containing information about the probable eruption time, duration, height of the ash plume and risk for population centers, were released to the Kamchatka Branch of the Russian Advisory Council. The copies of these documents were sent to participants of the KVERT (Kamchatka Volcano Eruption Response Team) project, uniting scientists Alaska Volcano Observatory, Institute of Volcanology and Seismology and KBGS. One explosive eruption was missed and only one false prediction (due to incorrect data) was made during this time period. Seismic precursors of sixteen explosive eruptions of Bezymianny were investigated using seismic data from both Bezymianny and nearby Kluchevskoy Volcano to improve risk assessment. It was determined that the successful prediction of a Bezymianny eruption depends strongly on the activity at Kluchevskoy.

Senyukov, S.

2010-12-01

322

Understanding Volcanoes  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on the three types of volcanoes: shield, cinder cone, and composite. Students research each type and then make models of each one to learn the distinctive properties of each type. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

Weisel, Frank

323

U.S. Geological Survey (USGS) Western Region Kasatochi Volcano Coastal and Ocean Science  

USGS Publications Warehouse

Alaska is noteworthy as a region of frequent seismic and volcanic activity. The region contains 52 historically active volcanoes, 14 of which have had at least one major eruptive event since 1990. Despite the high frequency of volcanic activity in Alaska, comprehensive studies of how ecosystems respond to volcanic eruptions are non-existent. On August 7, 2008, Kasatochi Volcano, in the central Aleutian Islands, erupted catastrophically, covering the island with ash and hot pyroclastic flow material. Kasatochi Island was an annual monitoring site of the U.S. Fish and Wildlife Service, Alaska Maritime National Wildlife Refuge (AMNWR); therefore, features of the terrestrial and nearshore ecosystems of the island were well known. In 2009, the U.S. Geological Survey (USGS), AMNWR, and University of Alaska Fairbanks began long-term studies to better understand the effects of the eruption and the role of volcanism in structuring ecosystems in the Aleutian Islands, a volcano-dominated region with high natural resource values.

DeGange, Anthony

2010-01-01

324

Lightning and electrical activity during the 2009 eruptions of Redoubt Volcano  

NASA Astrophysics Data System (ADS)

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.

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

325

Nyiragonga Volcano  

NASA Technical Reports Server (NTRS)

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.

2001-01-01

326

One hundred years of volcano monitoring in Hawaii  

USGS Publications Warehouse

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.

Kauahikaua, Jim; Poland, Mike

2012-01-01

327

Crisis GIS: Preparing for the Next Volcanic Crisis in the United States  

Microsoft Academic Search

Geographic Information Systems (GIS) specialists from the Volcano Hazards Program (VHP) of the U.S. Geological Survey (USGS), including personnel at Menlo Park, California, the Cascades Volcano Observatory in Vancouver, Washington, the Alaska Volcano Observatory in Anchorage and Fairbanks, Alaska, the Hawaiian Volcano Observatory in Hawaii National Park, Hawaii, and the Smithsonian Institution Global Volcanism Program in Washington, DC, are developing

D. W. Ramsey; J. E. Robinson; S. P. Schilling; J. R. Schaefer; P. Kimberly; F. A. Trusdell; M. C. Guffanti; G. C. Mayberry; C. E. Cameron; J. G. Smith; J. A. McIntire; S. Snedigar; J. W. Ewert

2004-01-01

328

Alaska GeoFORCE, A New Geologic Adventure in Alaska  

NASA Astrophysics Data System (ADS)

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.

Wartes, D.

2011-12-01

329

Grand Observatory  

NASA Technical Reports Server (NTRS)

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.

Young, Eric W.

2002-01-01

330

The EarthScope Plate Boundary Observatory Response to the 2006 Augustine Alaskan Volcanic Eruption  

NASA Astrophysics Data System (ADS)

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.

Pauk, B.; Feaux, K.; Jackson, M.; Friesen, B.; Enders, M.; Baldwin, A.; Fournier, K.; Marzulla, A.

2006-12-01

331

Widespread Lahar Inundation Around Mount Veniaminof Volcano: Evidence for a Major Late Holocene Eruption Involving Snow and Ice  

Microsoft Academic Search

Explosive eruptions at ice-clad volcanoes almost always results in the generation of lahars. In some cases, the extent of a lahar deposit is an indicator of the eruption magnitude as well as the volume of snow and ice available for interaction with hot eruptive products. At Mount Veniaminof volcano on the Alaska Peninsula, we have recently discovered a sequence of

C. F. Waythomas; T. P. Miller

2002-01-01

332

NeMO: New Millennium Observatory  

NSDL National Science Digital Library

NOAA's New Millennium Observatory (NeMO) "studies the dynamic interactions between submarine volcanic activity and seafloor hotsprings at an observatory, Axial seamount." The website presents a host of information on the participants, tools, and cruise plans for past, present, and scheduled expeditions. Researchers can learn about the Remote Access Sampler (RAS) and a Bottom Access Pressure Recorder (BPR) which transmits the latest data from the seafloor to the website. Through NeMO explorer, users can explore the seafloor with panorama, fly-throughs, and video clips. The education section offers stimulating curriculum materials where students can learn about mid-ocean ridges, hydrothermal vents, axial volcanoes, and much more.

333

Types of Volcanoes  

NSDL National Science Digital Library

This volcano resource introduces the six-type classification system and points out weaknesses of the classic three-type system. The six types of volcanoes are shield volcanoes, strato volcanoes, rhyolite caldera complexes, monogenetic fields, flood basalts, and mid-ocean ridges. For each type of volcano there is a description of both structure and dynamics along with examples of each. You can account for more than ninty percent of all volcanoes with these six types. Additionally, any system will be more useful if you use modifiers from the other potential classification schemes with the morphological types.

334

Geography World - Volcanoes  

NSDL National Science Digital Library

This portal provides links to an extensive list of volcano-related websites for the United States and around the world. Users can access articles, maps, glossaries, webcams, a dictionary of volcanoes, and many other resources.

335

Ol Doinyo Lengai Volcano  

USGS Multimedia Gallery

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....

2009-03-04

336

Volcanoes: Annenberg Media Project  

NSDL National Science Digital Library

Volcanoes is an exhibit from the Annenberg Media Project that provides a wealth of information about volcanoes and includes sections such as Melting Rocks, the Dynamic Earth, and Forecasting. Interactive exercises enable the user to learn how rock turns into magma, how to locate volcanoes, and how to decide if building a project near a volcano is safe. Quicktime videos are used for each of the six categories to illustrate the points outlined in the text.

1997-01-01

337

How Volcanoes Work  

NSDL National Science Digital Library

This educational resource describes the science behind volcanoes and volcanic processes. Topics include volcanic environments, volcano landforms, eruption dynamics, eruption products, eruption types, historical eruptions, and planetary volcanism. There are two animations, over 250 images, eight interactive tests, and a volcano crossword puzzle.

2011-04-18

338

A Scientific Excursion: Volcanoes.  

ERIC Educational Resources Information Center

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)

Olds, Henry, Jr.

1983-01-01

339

Where are the Volcanoes?  

NSDL National Science Digital Library

This formative assessment item discusses common misconceptions about volcano location around the world. Resources include background and content information as well as alignment to the National Science Education Standards. The probe could easily be modified to be used with a study of earthquakes instead of volcanoes. Teachers can access other resources including facts about volcanoes and lesson ideas.

Fries-Gaither, Jessica

340

Volcano Vents  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 5 May 2003

This low-relief shield volcano imaged with the THEMIS visible camera has two large vents which have erupted several individual lava flows. The positions of the origins of many of the flows indicate that it is probable that the vents are secondary structures that formed only after the shield was built up by eruptions from a central caldera.

Image information: VIS instrument. Latitude 17.6, Longitude 243.6 East (116.4 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2003-01-01

341

MATLAB tools for improved characterization and quantification of volcanic incandescence in Webcam imagery; applications at Kilauea Volcano, Hawai'i  

USGS Publications Warehouse

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.

Patrick, Matthew R.; Kauahikaua, James P.; Antolik, Loren

2010-01-01

342

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)

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.

Stovall, W. K.; Randall, M. J.; Cervelli, P. F.

2011-12-01

343

Investigating Geothermal Activity, Volcanic Systems, and Deep Tectonic Tremor on Akutan Island, Alaska, with Array Seismology  

NASA Astrophysics Data System (ADS)

In addition to hosting one of the most active volcanoes in the Aleutian Arc, Akutan Island, Alaska, is the site of a significant geothermal resource within Hot Springs Bay Valley (HSBV). We deployed 15 broadband (30 s to 50 Hz) seismometers in and around HSBV during July 2012 as part of an effort to establish a baseline for background seismic activity in HSBV prior to geothermal production on the island. The stations recorded data on-site and were retrieved in early September 2012. Additional targets for the array include the tracking of deep tectonic tremor known to occur within the Aleutian subduction zone and the characterization of volcano-tectonic (VT) and deep long period (DLP) earthquakes from Akutan Volcano. Because 13 of the stations in the array sit within an area roughly 1.5 km by 1.5 km, we plan to apply methods based on stacking and beamforming to analyze the waveforms of extended signals lacking clear phase arrivals (e.g., tremor). The average spacing of the seismometers, roughly 350 m, provides sensitivity to frequencies between 2-8 Hz. The stacking process also increases the signal-to-noise ratio of small amplitude signals propagating across the array (e.g., naturally occurring geothermal seismicity). As of August 2012, several episodes of tectonic tremor have been detected in the vicinity of Akutan Island during the array deployment based on recordings from nearby permanent stations operated by the Alaska Volcano Observatory (AVO). This is the first small-aperture array deployed in the Aleutian Islands and the results should serve as a guide for future array deployments along the Aleutian Arc as part of the upcoming EarthScope and GeoPRISMS push into Alaska. We demonstrate the power of array methods based on stacking at Akutan Volcano using a sequence of DLP earthquakes from June 11, 2012 that were recorded on the permanent AVO stations. We locate and characterize the lowest frequency portion of the signals at 0.5 Hz. At these low frequencies, the traditional "sparse" local network at Akutan effectively becomes a small-aperture array relative to the wavelength. We exploit the coherency among the stations and locate the DLPs by using a novel stacking method. The crux of the method involves scanning over all possible source locations and relative polarity combinations between the local stations to find the one that maximizes the stacked power at a well-defined region in the subsurface. As a result, the method is applicable even in the presence of mixed polarities. We discover that two of the stations at Akutan have DLP waveforms with opposite polarities compared to the other stations. Accounting for this polarity variation gives a DLP source location at 10 km depth, to the west-southwest of the Akutan summit caldera. These results give clear evidence for non-isotropic radiation patterns associated with DLPs and show the promise of array methods based on waveform stacking for providing future insights into the origin of volcanic as well as geothermal and tectonic seismicity.

Haney, M. M.; Prejean, S. G.; Ghosh, A.; Power, J. A.; Thurber, C. H.

2012-12-01

344

Lowell Observatory  

NSDL National Science Digital Library

Home of the Clark Telescope, the Lowell Observatory's mission is to pursue the study of astronomy, especially the study of our solar system and its evolution, to conduct pure research in astronomical phenomena, and to maintain quality public education and outreach programs to bring the results of astronomical research to the general public. The Steele Visitor Center, the staging area for all daytime tours and evening programs, also houses the interactive exhibit hall, the Giclas Lecture Hall, and more. Known for its solar system research, Lowell astronomers are conducting investigations of near-Earth asteroids, planetary satellites and ring systems, Centaurs, Kuiper Belt objects, and comets. A decades long study of the photometric stability of the Sun also continues. The Discovery Channel Telescope is Lowell Observatoryâs newest project to design and construct a powerful, 4.2-meter telescope. Currently under development, the Discovery Channel Telescope will significantly advance Lowellâs scientific research capabilities while providing opportunities for real-time global broadcasting and educational programming about astronomy and science.

345

Haystack Observatory  

NASA Technical Reports Server (NTRS)

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.

1972-01-01

346

Global Volcano Model  

NASA Astrophysics Data System (ADS)

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.

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

347

The Plate Boundary Observatory Component of the EarthScope Facility  

Microsoft Academic Search

The Plate Boundary Observatory (PBO), one of the core components of EarthScope, is a geodetic observatory designed to study the three-dimensional strain field resulting from plate boundary deformation in the western US including Alaska. The science goals of PBO require that plate boundary deformation be adequately characterized over the wide range of temporal and spatial scales common to active continental

M. Jackson; W. Prescott

2003-01-01

348

Alaska Resource Data File, Noatak Quadrangle, Alaska  

USGS Publications Warehouse

This report gives descriptions of the mineral occurrences in the Noatak 1:250,000-scale quadrangle, Alaska. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska.

Grybeck, Donald J.; Dumoulin, Julie A.

2006-01-01

349

Measurements of artificial periodic inhomogeneities at HIPAS Observatory  

Microsoft Academic Search

Results are presented from recent experiments that employ high-power, high- frequency (HF) radio waves to probe the mesosphere and lower thermosphere. The measurements were made at the High-Power Auroral Stimulation (HIPAS) Observatory located near Fairbanks, Alaska. One objective of the study was to determine the feasibility of using artificial electron density perturbations created in the auroral environment to measure the

F. T. Djuth; K. M. Groves; J. H. Elder; E. R. Shinn; J. M. Quinn; J. Villasenor; A. Y. Wong

1997-01-01

350

Erupting Volcano Mount Etna  

NASA Technical Reports Server (NTRS)

An Expedition Two crewmember aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

2001-01-01

351

Nobeyama Radio Observatory  

NASA Astrophysics Data System (ADS)

Nobeyama Radio Observatory has telescopes at millimeter and submillimeter wavelengths. It was established in 1982 as an observatory of Tokyo Astronomical Observatory (NATIONAL ASTRONOMICAL OBSERVATORY, JAPAN since 1987), and operates the 45 m telescope, Nobeyama Millimeter Array, and Radioheliograph. High-resolution images of star forming regions and molecular clouds have revealed many aspects of...

Murdin, P.

2000-11-01

352