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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

AVO: Alaska Volcano Observatory  

NSDL National Science Digital Library

This site illustrates the Alaska Volcano Observatory's (AVO) objective to monitor Alaska's volcanoes for the purpose of forecasting volcanic activity and alleviating hazards. AVO's seismometers and satellite imagery allow visitors to obtain current information on selected volcanoes. Because AVO is responsible for volcanic emergencies, people in Alaska can visit the Web site to determine their vulnerability. The site also features AVO's research in geological mapping, modeling of magnetic systems, and development of new instrumentation for predication and interpretation of volcanic unrest. Everyone can appreciate the images of past volcanic eruptions.

3

The Alaska Volcano Observatory - Expanded Monitoring of Volcanoes Yields Results  

USGS Publications Warehouse

Recent explosive eruptions at some of Alaska's 52 historically active volcanoes have significantly affected air traffic over the North Pacific, as well as Alaska's oil, power, and fishing industries and local communities. Since its founding in the late 1980s, the Alaska Volcano Observatory (AVO) has installed new monitoring networks and used satellite data to track activity at Alaska's volcanoes, providing timely warnings and monitoring of frequent eruptions to the aviation industry and the general public. To minimize impacts from future eruptions, scientists at AVO continue to assess volcano hazards and to expand monitoring networks.

Brantley, Steven R.; McGimsey, Robert G.; Neal, Christina A.

2004-01-01

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

Volcanic Activity in Alaska: Summary of Events and Response of the Alaska Volcano Observatory, 1992.  

National Technical Information Service (NTIS)

During 1992, the Alaska Volcano Observatory (AVO) responded to 10 eruptions, episodes of eruptive activity, or false alarms at 8 volcanoes--Spurr, Redoubt, Iliamna, Mageik, Westdahl, Akutan, Bogoslof, and Seguam--located from upper Cook Inlet to 1770 km o...

C. A. Neal M. P. Doukas R. G. McGimsey

1995-01-01

6

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

7

Volcanic Activity in Alaska and Kamchatka: Summary of Events and Response of the Alaska Volcano Observatory, 2003.  

National Technical Information Service (NTIS)

The Alaska Volcano Observatory (AVO) monitors the more than 40 historically active volcanoes of the Aleutian Arc. Of these, 24 were considered monitored in real time with short-period seismic instrument networks as of the end of 2003 (Dixon and others, 20...

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

2005-01-01

8

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

9

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

10

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

11

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

12

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

13

The Earthscope Plate Boundary Observatory Akutan Alaskan Volcano Network Installation  

Microsoft Academic Search

During June and July of 2005, the Plate Boundary Observatory (PBO) installed eight permanent GPS stations on Akutan Volcano, in the central Aleutian Islands of Alaska. PBO worked closely with the Alaska Volcano Observatory and the Magmatic Systems Site Selection working group to install stations with a spatial distribution to monitor and detect both short and long term volcanic deformation

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

2005-01-01

14

Satellite monitoring of remote volcanoes improves study efforts in Alaska  

Microsoft Academic Search

Satellite monitoring of remote volcanoes is greatly benefitting the Alaska Volcano Observatory (AVO), and last year's eruption of the Okmok Volcano in the Aleutian Islands is a good case in point. The facility was able to issue and refine warnings of the eruption and related activity quickly, something that could not have been done using conventional seismic surveillance techniques, since

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

1998-01-01

15

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

NASA Astrophysics Data System (ADS)

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

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

16

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

17

Stratigraphic framework of Holocene volcaniclastic deposits, Akutan Volcano, east-central Aleutian Islands, Alaska  

Microsoft Academic Search

Akutan Volcano is one of the most active volcanoes in the Aleutian arc, but until recently little was known about its history and eruptive character. Following a brief but sustained period of intense seismic activity in March 1996, the Alaska Volcano Observatory began investigating the geology of the volcano and evaluating potential volcanic hazards that could affect residents of Akutan

Christopher F. Waythomas

1999-01-01

18

Tsunami Warning Protocol for Eruptions of Augustine Volcano, Cook Inlet, Alaska  

Microsoft Academic Search

Augustine is an island volcano that has generated at least one tsunami. During its January 2006 eruption coastal residents of lower Cook Inlet became concerned about tsunami potential. To address this concern, NOAA's West Coast\\/ Alaska Tsunami Warning Center (WC\\/ATWC) and the Alaska Volcano Observatory (AVO) jointly developed a tsunami warning protocol for the most likely scenario for tsunami generation

P. Whitmore; C. Neal; D. Nyland; T. Murray; J. Power

2006-01-01

19

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.

20

Cascades Volcano Observatory - Learn About Volcanoes: Frequently Asked Volcano Questions  

NSDL National Science Digital Library

This page provides the answers to frequently asked questions about volcanoes. It is created by the United States Geological Survey. Topics addressed include: What Is A Volcano? Why Do Volcanoes Occur? How Do Volcanoes Erupt? Where Do Volcanoes Occur? When Will A Volcano Erupt? How Hot Is A Volcano? Can Lava Be Diverted? Do Volcanoes Affect Weather? What Types of Volcanoes are There? Which Eruptions Were The Deadliest? 20th Century Volcanic Eruptions and Their Impact. About 60 additional questions with answers are available under MORE FAQ's -Volcano Questions and Answers, and includes some sections on volcanoes of the western United States. Other links to volcano information are also available.

21

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

22

Stratigraphic framework of Holocene volcaniclastic deposits, Akutan Volcano, east-central Aleutian Islands, Alaska  

Microsoft Academic Search

Akutan Volcano is one of the most active volcanoes in the Aleutian arc, but until recently little was known about its history\\u000a and eruptive character. Following a brief but sustained period of intense seismic activity in March 1996, the Alaska Volcano\\u000a Observatory began investigating the geology of the volcano and evaluating potential volcanic hazards that could affect residents\\u000a of Akutan

Christopher F. Waythomas

1999-01-01

23

Estimates of Gas Flux From Infrasonic Recordings of Vulcanian Blasts at Augustine Volcano, Alaska  

Microsoft Academic Search

In January 2006, Augustine volcano awoke from nearly 20 years of quiescence. The 2006 eruption lasted nearly three months and included discrete explosive, continuous explosive and effusive phases. The eruption was well-monitored by the Alaska Volcano Observatory, with a network that included dense seismic and geodetic instrumentation. Co-located with one of the seismometers was a pressure sensor which captured the

J. Caplan-Auerbach; A. K. Bellesiles; J. J. Fernandes

2008-01-01

24

USGS: Cascades Volcano Observatory Educational Outreach  

NSDL National Science Digital Library

Reaching out to a volcano can be a precarious enterprise. Reaching out to teach young people about volcanoes and related geological matters is less precarious, particularly after discovering this site. Created by staff members at the United States Geological Survey's Cascades Volcano Observatory, this site brings together educational materials such as short videos, printable posters, and fact sheets. Teachers may wish to start at the "Learn About Volcanoes" area. Here they will find resources that will help them teach students about volcano terminology, eruption histories, and the answer to the question "Can Lava Be Diverted?" Moving along, the "Special Features and Useful Pages" includes interactive photo tours of Mount Rainier and an excellent timetable of the Cascade Range.

2007-11-28

25

The Earthscope Plate Boundary Observatory Akutan Alaskan Volcano Network Installation  

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

26

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

27

The Reawakening of Alaska's Augustine Volcano  

Microsoft Academic Search

Augustine volcano, in south central Alaska, ended a 20-year period of repose on 11 January 2006 with 13 explosive eruptions in 20 days. Explosive activity shifted to a quieter effusion of lava in early February, forming a new summit lava dome and two short, blocky lava flows by late March (Figure 1). The eruption was heralded by eight months of

John A. Power; Christopher J. Nye; Michelle L. Coombs; Rick L. Wessels; Peter F. Cervelli; John Dehn; Kristi L. Wallace; Jeffery T. Freymueller; Michael P. Doukas

2006-01-01

28

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

29

Location of eruption-related earthquake clusters at Augustine Volcano, Alaska, using station-pair differential times  

Microsoft Academic Search

Families of similar earthquakes at shallow depths occurring over multiple timescales have been identified prior to and during the 2005-2006 eruption of Augustine Volcano. The use of conventional and double-difference location methods failed to result in stable locations, due primarily to noisy site conditions as well as unfavourable station geometry for the Alaska Volcano Observatory stations. Previous work found that

Laura Sumiejski; Clifford Thurber; Heather R. Deshon

2009-01-01

30

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

National Technical Information Service (NTIS)

To provide Yellowstone National Park (YNP) and its surrounding communities with a modern, comprehensive system for volcano and earthquake monitoring, the Yellowstone Volcano Observatory (YVO) has developed a monitoring plan for the period 20062015. Such a...

2006-01-01

31

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.

32

The Reawakening of Alaska's Augustine Volcano  

NASA Astrophysics Data System (ADS)

Augustine volcano, in south central Alaska, ended a 20-year period of repose on 11 January 2006 with 13 explosive eruptions in 20 days. Explosive activity shifted to a quieter effusion of lava in early February, forming a new summit lava dome and two short, blocky lava flows by late March (Figure 1). The eruption was heralded by eight months of increasing seismicity, deformation, gas emission, and small phreatic eruptions, the latter consisting of explosions of steam and debris caused by heating and expansion of groundwater due to an underlying heat source.

Power, John A.; Nye, Christopher J.; Coombs, Michelle L.; Wessels, Rick L.; Cervelli, Peter F.; Dehn, John; Wallace, Kristi L.; Freymueller, Jeffery T.; Doukas, Michael P.

2006-09-01

33

Volcanoes Galore!  

NSDL National Science Digital Library

Here, you can check out videos and links to lots of nifty volcano stuff. Have fun! This is completely unrelated...but check it out anywho. sweet periodic table! Alaska Volcano Observatory Earthquakes and Volcanoes Check this one out for info on history\\'s most distructive volcano. Exploring Pompeii and Vesuvius Exploring the Environment: Volcanoes This will give you lots of background on how Volcanoes work, what the major parts are, and how they erupt. How Volcanoes Work A quick video on how to take a lava sample...hot! Lava Sampling on Kilauea Volcano, Hawai i A volcano in antartica? ...

Syracuse, Mr.

2008-06-11

34

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

35

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

36

Developing monitoring capability of a volcano observatory: the example of the Vanuatu Geohazards Observatory  

Microsoft Academic Search

Vanuatu lies on the Pacific 'Ring of Fire'. With 6 active subaerial and 3 submarine (identified so far) volcanoes, monitoring and following up their activities is a considerable work for a national observatory. The Vanuatu Geohazards Observatory is a good example of what can be done from `scratch' to develop a volcanic monitoring capability in a short space of time.

S. Todman; E. Garaebiti; G. E. Jolly; S. Sherburn; B. Scott; A. D. Jolly; N. Fournier; C. A. Miller

2010-01-01

37

OPERATIONAL USE OF INSAR FOR VOLCANO OBSERVATORIES: EXPERIENCE IN LOCAL RECEPTION AT MONTSERRAT  

Microsoft Academic Search

A volcano observatory that is monitoring an erupting volcano(es) needs as much relevant data as it can get in a timely manner. InSAR has, potentially, a major role to play in delivering information on ground deformation and topographic change that can feed into the crisis management process. The Montserrat Volcano Observatory (MVO) has been observing the ongoing eruption of the

G. Wadge; L. Cabey; S. Lomas-Clarke; M. D. Palmer; A. Smith

38

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

39

Mount Dutton volcano, Alaska: Aleutian arc analog to Unzen volcano, Japan  

Microsoft Academic Search

Holocene eruptions from Mount Dutton, a small Late Quaternary volcano near the tip of the Alaska Peninsula, bear strong physical and petrologic similarities to the 1990–1995 Unzen Fugendake eruption in Japan. The volcano had a protracted phase of effusive calcalkaline andesitic (54–59 wt.% SiO2) cone-building in the late Pleistocene followed by an abrupt switch to more silicic (?65 wt.% SiO2)

T. P Miller; D. G Chertkoff; J. C Eichelberger; M. L Coombs

1999-01-01

40

Tsunami Warning Protocol for Eruptions of Augustine Volcano, Cook Inlet, Alaska  

NASA Astrophysics Data System (ADS)

Augustine is an island volcano that has generated at least one tsunami. During its January 2006 eruption coastal residents of lower Cook Inlet became concerned about tsunami potential. To address this concern, NOAA's West Coast/ Alaska Tsunami Warning Center (WC/ATWC) and the Alaska Volcano Observatory (AVO) jointly developed a tsunami warning protocol for the most likely scenario for tsunami generation at Augustine: a debris avalanche into the Cook Inlet. Tsunami modeling indicates that a wave generated at Augustine volcano could reach coastal communities in approximately 55 minutes. If a shallow seismic event with magnitude greater than 4.5 occurred near Augustine and the AVO had set the level of concern color code to orange or red, the WC/ATWC would immediately issue a warning for the lower Cook Inlet. Given the short tsunami travel times involved, potentially affected communities would be provided as much lead time as possible. Large debris avalanches that could trigger a tsunami in lower Cook Inlet are expected to be accompanied by a strong seismic signal. Seismograms produced by these debris avalanches have unique spectral characteristics. After issuing a warning, the WC/ATWC would compare the observed waveform with known debris avalanches, and would consult with AVO to further evaluate the event using AVO's on-island networks (web cameras, seismic network, etc) to refine or cancel the warning. After the 2006 eruptive phase ended, WC/ATWC, with support from AVO and the University of Alaska Tsunami Warning and Environmental Observatory for Alaska program (TWEAK), developed and installed "splash-gauges" which will provide confirmation of tsunami generation.

Whitmore, P.; Neal, C.; Nyland, D.; Murray, T.; Power, J.

2006-12-01

41

Geologic Studies in Alaska by the U.S. Geological Survey, 1999.  

National Technical Information Service (NTIS)

The collection of nine papers that follow continue the series of U.S. Geological Survey (USGS) investigative reports in Alaska under the broad umbrella of the geologic sciences. Contents: Redoubt Volcano and the Alaska Volcano Observatory, 10 years later;...

L. P. Gough F. H. Wilson

2001-01-01

42

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

USGS Publications Warehouse

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

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

2011-01-01

43

The 1931 Eruption of Aniakchak Volcano, Alaska  

Microsoft Academic Search

One of the largest Aleutian Arc eruptions of the 20th century was the 1931 intracaldera eruption of Aniakchak Volcano, with an erupted volume of 0.3 to 0.5 km3. The eruption, which varied in intensity, style, and composition, persisted for approximately 6 weeks, dispersing ash as far as 600 km to the north. The eruption was first noticed when a large

R. S. Nicholson; C. A. Neal; J. E. Gardner

2002-01-01

44

Record of Late Holocene debris avalanches and lahars at Iliamna Volcano, Alaska  

Microsoft Academic Search

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 10,000yr. 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

C. F. Waythomas; T. P. Miller; J. E. Begét

2000-01-01

45

SAR measurements of surface displacements at Augustine volcano, Alaska from 1992 to 2005  

Microsoft Academic Search

Augustine volcano is an active stratovolcano located at the southwest of Anchorage, Alaska. Augustine volcano had experienced seven significantly explosive eruptions in 1812, 1883, 1908, 1935, 1963, 1976, and 1986, and a minor eruption in January 2006. We measured the surface displacements of the volcano by radar interferometry and GPS before and after the eruption in 2006. ERS-1\\/2, RADARSAT-1 and

C.-W. Lee; Z. Lu; O.-I. Kwoun

2007-01-01

46

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

47

Economic and engineering considerations for geothermal development in the Makushin Volcano Region of Unalaska Island, Alaska  

SciTech Connect

Large vapor-dominated hydrothermal reservoirs are suspected to exist in the region marked by fumarole fields on the southeast flank of Makushin Volcano on Unalaska Island, Alaska. In this paper, economic and engineering considerations with respect to potential hydrothermal development in the Makushin Volcano region are presented.

Reeder, J.W.; Economides, M.J.; Markle, D.R.

1982-10-01

48

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

Microsoft Academic Search

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

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

2008-01-01

49

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

50

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

51

The 1996 Earthquake Swarm and Intrusion at Akutan Volcano, Alaska: An Example of a Failed Eruption  

NASA Astrophysics Data System (ADS)

In March 1996, Akutan Volcano, in the central Aleutian Arc, was the source of a powerful swarm of Volcano- Tectonic (VT) earthquakes composed of more than 200 shocks greater than magnitude 3.5 (Mmax = 5.1) that produced an estimated total cumulative seismic moment of 2.7 X 1018 N m. The swarm consisted of two pulses that began on March 11 and March 14: elevated earthquake activity continued at Akutan Volcano for several months. Extensive ground cracks that striking N70W and extending discontinuously across the island from near Lava Point (the most recently active satellite vent) to the southeast side of the island formed in association with this swarm. The most extensive cracks formed a zone that is 500 m wide and 3 km long on the NW flank of the volcano between the summit and Lava Point. In this area, local graben structures show vertical displacements of 30 to 80 cm, suggesting the cracks formed in response to uplift of this portion of the volcano. Results from both C-band ERS and L-band JERS radar interferometry images that span the time of the swarm reveal a complex island-wide pattern of deformation: The western part of the island moved upward as much as 70 cm, while the eastern part moved downward a similar amount. The most plausible interpretation is that the 1996 seismic swam and associated ground deformation at Akutan resulted from an intrusion of magma beneath the northwest flank of the volcano. Modeling of the observed deformation field suggests the inflation on the northwest side of the volcano results from the intrusion of a dike with a top at 0.4 km depth, while the deflation on the island's eastern side is modeled as several dislocation planes that possibly reflect the depressurization of a known hydrothermal system in this area. Earthquake hypocenters calculated between 1996 and 2008 are consistent with this model and show (a) a prominent cluster of shallow earthquake hypocenters that occurred on the eastern side of the island near the center of subsidence in 1996, (b) a west-northwest trend in hypocenters that aligns with the observed ground cracks and extends across the island, and (c) a small cluster of low- and mixed-frequency events that locate at mid-crustal depths beneath the volcano's southwest flank. In spite of this high level of volcanic unrest in 1996 no subsequent magmatic eruption has occurred at Akutan in association with or since this swarm. The seismic moment and ground deformation observed at Akutan in 1996 greatly exceeds many sequences that precede eruptions at other volcanoes. Remarkably, no observed increases in fumorolic activity or gas emission and no obvious periods of volcanic tremor or long- period seismic events were observed in association with the 1996 seismic swarm. The lack of these key precursors played a strong role in diagnosing the unrest and formulating public warnings and advisories issued by the Alaska Volcano Observatory during the 1996 seismic crisis.

Power, J. A.; Lu, Z.; Prejean, S. G.; Wicks, C.; Dzurisin, D.

2008-12-01

52

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

53

The 1997 Eruption of Okmok Volcano, Alaska, a Synthesis of Remotely Sensed Data  

NASA Astrophysics Data System (ADS)

Okmok Volcano in the central Aleutian Islands erupted in February of 1997. The eruption produced a lava flow in the central caldera over 5.5 x107 m3 in volume over 7.5 km2. This caldera is the most active of the Aleutian Arc, and is now the focus of international multidisciplinary studies. A synthesis of remotely sensed data (AIRSAR, derived DEMs, Landsat MSS and TM data, AVHRR, ERS, JERS, Radarsat) has given a sequence of events for the virtually unobserved 1997 eruption. Elevation data from the AIRSAR sensor acquired in October 2000 over Okmok was used to create a 5m resolution DEM mosaic of Okmok. AVHRR night-time imagery has been analyzed between February 13 and April 11, 1997. Landsat imagery years before and after the eruption allow us to accurately determine the extent of the new flow. The flow began without precursory thermal anomalies on Feburary 13th. At this point, the flow was a large single lobe, flowing north, ranging in thickness from 4 to 20 m. The eruption rate of this flow in the early stages is estimated as 2.5 m3/s. According to AVHRR Band 3 and 4 radiance data and ground observations (overflight on Feb. 28), the first lobe had reached its maximum extent by February 28, while a second, smaller lobe began effusion sometime between March 1st - 4th. This is based on a jump in the thermal and volumetric flux determined from satellite imagery, and the physical size of the thermal anomalies. This flow continued with an eruptive rate of about 5 m3/s. The total AVHRR radiance reached a maximum on March 12, which may indicate the peak areal extent for both lobes. Total radiance values waned after March 26, indicating lava effusion had ended and a cooling crust had formed. The total volume determined by eruption rates over time (ca. 1 x 108 m3) agree well with the volume of the flow estimated using radar, Landsat, and later ground observations. Remote sensing has become an integral part of the Alaska Volcano Observatory's monitoring and hazard mitigation efforts. Studies like this allow access to remote volcanoes, and provide new methods to monitor potentially dangerous volcanoes.

Moxey, L.; Dehn, J.; Papp, K.; Patrick, M.; Guritz, R.

2001-12-01

54

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

55

Sustained long-period seismicity at Shishaldin Volcano, Alaska  

USGS Publications Warehouse

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

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

2006-01-01

56

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

57

Tsunamis Generated by Eruptions from Mount St. Augustine Volcano, Alaska  

Microsoft Academic Search

During an eruption of the Alaskan volcano Mount St. Augustine in the spring of 1986, there was concern about the possibility that a tsunami might be generated by the collapse of a portion of the volcano into the shallow water of Cook Inlet. A similar edifice collapse of the volcano and ensuing sea wave occurred during an eruption in 1883.

Jurgen Kienle; Zygmunt Kowalik; T. S. Murty

1987-01-01

58

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

Microsoft Academic Search

The three-dimensional P and S wave structure of Redoubt Volcano, Alaska, and the underlying crust to depths of 7-8 km is determined from 6219 P wave and 4008 S wave first-arrival times recorded by a 30-station seismograph network deployed on and around the volcano. First-arrival times are calculated using a finite-difference technique, which allows for flexible parameterization of the slowness

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

1996-01-01

59

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

Microsoft Academic Search

The 1986 eruption of Augustine Volcano, Alaska, was remarkable for its sustained compositional heterogeneity. Magmas with 56-64 wt % bulk-rock SiO2 were erupted throughout the six-month eruption in both early explosive and later effusive phases, raising questions as to the nature of magma storage and interaction beneath this young and frequently active volcano. Linear trends in major element variation diagrams

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

2006-01-01

60

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

Microsoft Academic Search

Compositional heterogeneity (56-64 wt% SiO2 whole-rock) in samples of tephra and lava from the 1986 eruption of Augustine Volcano, Alaska, raises questions about the physical nature of magma storage and interaction beneath this young and frequently active volcano. To determine conditions of magma storage and evolutionary histories of compositionally distinct magmas, we investigate physical and chemical characteristics of andesitic and

Diana C. Roman; Katharine V. Cashman; Cynthia A. Gardner; Paul J. Wallace; John J. Donovan

2006-01-01

61

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

Microsoft Academic Search

Compositional heterogeneity (56–64 wt% SiO2 whole-rock) in samples of tephra and lava from the 1986 eruption of Augustine Volcano, Alaska, raises questions about the\\u000a physical nature of magma storage and interaction beneath this young and frequently active volcano. To determine conditions\\u000a of magma storage and evolutionary histories of compositionally distinct magmas, we investigate physical and chemical characteristics\\u000a of andesitic and dacitic

Diana C. Roman; Katharine V. Cashman; Cynthia A. Gardner; Paul J. Wallace; John J. Donovan

2006-01-01

62

An overview of the 2009 eruption of Redoubt Volcano, Alaska  

NASA Astrophysics Data System (ADS)

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

Bull, Katharine F.; Buurman, Helena

2013-06-01

63

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

Microsoft Academic Search

The 1931A.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

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

2011-01-01

64

Analysis of the geodetic record of the 2009 eruption of Redoubt Volcano, Alaska  

Microsoft Academic Search

Redoubt volcano, about 160 km to the SW of Anchorage, Alaska began its most recent eruption in March 2009. After an initial month of alternating explosive events and dome extrusions, dome growth continued at least for another two months into June 2008 and may still persist at small rates. No continuously recording GPS instrumentation existed within 25 km of Redoubt

Ronni Grapenthin; Jeff Freymueller; Peter Cervelli

2010-01-01

65

Basaltic thermals and Subplinian plumes: Constraints from acoustic measurements at Shishaldin volcano, Alaska  

Microsoft Academic Search

The 1999 basaltic eruption of Shishaldin volcano (Alaska, USA) included both Strombolian and Subplinian activity, as well as a “pre-Subplinian” phase interpreted as the local coalescence within a long foam in the conduit. Although few visual observations were made of the eruption, a great deal of information regarding gas velocity, gas flux at the vent and plume height may be

Sylvie Vergniolle; Jacqueline Caplan-Auerbach

2006-01-01

66

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

Microsoft Academic Search

Augustine, an island volcano located approximately 275 km SSW of Anchorage, Alaska, produced thirteen discrete ash plumes during an explosive eruption phase that lasted from January 11 to January 28, 2006, followed by continuous ash emissions from January 29 to February 2. Immediately after the first two explosive eruptions on the morning of January 11, an eight-stage DRUM aerosol impactor

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

2006-01-01

67

SEISMIC RECORDINGS OF ICE AND DEBRIS AVALANCHES OF ILIAMNA VOLCANO, ALASKA  

Microsoft Academic Search

Seismic data recorded on Iliamna Volcano, Alaska, indicate that Iliamna ice avalanches are preceded by up to several hours of p recursory seismicity. This precursory activity is represented by a 1-3 hour period of activity comprising a sequence of discrete repeatin g earthquakes and a period of continuous groundshaking that builds in amplitude. The avalanche itself is represented by a

Jacqueline Caplan-Auerbach; Stephanie G. Prejean; John A. Power

68

Precursory seismicity associated with frequent, large ice avalanches on Iliamna volcano, Alaska, USA  

Microsoft Academic Search

Since 1994, at least six major (volume >106 m3) ice and rock avalanches have occurred on Iliamna volcano, Alaska, USA. Each of the avalanches was preceded by up to 2 hours of seismicity believed to represent the initial stages of failure. Each seismic sequence begins with a series of repeating earthquakes thought to represent slip on an ice-rock interface, or

Jacqueline Caplan-Auerbach; Christian Huggel

2007-01-01

69

Gas Emissions From Augustine Volcano, Alaska 1995-2006  

NASA Astrophysics Data System (ADS)

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 March 2006, lava extrusion and generation of block and ash flows dominated. By the end of March, a significant lava dome/flow complex had been emplaced and volcanic activity began to subside. Annual airborne gas measurements detected no anomalous degassing carbon dioxide, sulfur dioxide and hydrogen sulfide from 1995 through spring 2005. In fact, measurements made on May 10, 2005, shortly after the onset of small-scale anomalous seismicity showed Augustine to be producing essentially no measurable volcanic gases. The next measurement, for SO2 only, on December 20, 2005, revealed an emission rate of 600 td-1 (metric tons per day). It was not until the following measurement on January 4, 2006, that the SO2 output jumped to a high level with a measured emission rate of 6700 td-1. Based on reports from residents on the lower Kenai Peninsula of hydrogen sulfide odors, the majority of earlier sulfur emission from Augustine during the pre-explosive or precursory phase was likely in the form of hydrogen sulfide, consistent with early scrubbing of the SO2 by water. The first measurement of CO2 emission at 5000 td-1 was made on January 16, 2006, several days after the first vulcanian explosions. This was followed three days later with a measurement of 6000 td-1 CO2. These two measurements were made during a period of active lava extrusion at the summit. The highest CO2 emission rate during the eruption, 13,000 td-1, was measured on March 9, 2006, during a period of intense seismicity and extrusion. We speculate that had CO2 measurements been possible during the precursory stage of unrest in late 2005, the levels would have also been very high, reflecting the ascent of magma to shallow levels below the volcano. The last CO2 measurement on April 27, 2006 (600 td-1) indicated that CO2 had declined to a relatively low level and the influx of new magma had largely ceased. Although only a few measurements were made, the highest emission rate measured for hydrogen sulfide was 6 td-1 on January 24, 2006. Twenty-three SO2 measurements were made during the eruptive episode with the highest reading at 7800 td-1 on March 9, 2006 during a period of rapid lava extrusion. That high value, however, was still only about one-third that of the high value of 24,000 td-1 reported during an explosive, ash-producing episode of the 1986 Augustine eruption. By May 2006, SO2 emission rates had declined to the 200-400 td-1 level.

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

2006-12-01

70

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

71

Causation or coincidence? The correlations in time and space of the 2008 eruptions of Cleveland, Kasatochi, and Okmok Volcanoes, Alaska  

NASA Astrophysics Data System (ADS)

In mid-summer 2008, three significant volcanic eruptions occurred in the Andreanof Islands of the Aleutian Arc, Alaska. Okmok volcano began erupting on July 12, followed by Cleveland on July 21, and then by Kasatochi on August 7. In addition to this temporal correlation, there is also a geographic correlation: the eruptions occurred in a 525 km region representing only about 20% of the arc's length. Given these close proximities in space and time, it is natural to speculate about whether an underlying process is at work. Ultimately, the arc exists because of subduction, but the question remains if a more immediate trigger may be responsible for the concurrence. We began our inquiry into whether a link exists among the three eruptions by posing the following question: What is the probability that, by chance alone, Okmok, Kasatochi and Cleveland could simultaneously erupt? Answering this question requires both a statistical model for eruption frequency and empirical data of where and when eruptions have occurred in the past. We assume that eruptions follow a Poisson distribution, and estimate the expected number of eruptions per time interval for each volcano in the arc from the geologic record and observations contained in the Alaska Volcano Observatory's GeoDIVA database. We then perform a Monte Carlo experiment, simulating 10,000 years of eruptive activity at 30 day intervals. The results of the simulation indicate that the phenomenon of three eruptions beginning in a single month happens about once every 90 years. A spatial constraint requiring that the maximum separation among the volcanoes be less than 525 km increases this interval to about once every 900 years. Though these intervals are not so long as to rule out coincidence, they are long enough to warrant further investigation into the possibility of a common origin. Several candidates for a prospective cause are: (1) the Great Aleutian Earthquake of 1957, which includes the region of the three recent eruptions, may have triggered a period of increased volcanic activity that still persists; (2) a slow slip event, with associated non- volcanic tremor, have may have resulted in static stress changes favorable to volcanic eruptions; or (3) nearby volcanoes may interact with one another in such a way as to increase the chance of clustered eruptions. We consider each of these scenarios (as well as other more remote possibilities) and weigh their relative likelihoods against the probability of random correlation. In the end, no definitive answer emerges, though pure coincidence remains a simple and plausible explanation for this remarkable event.

Cervelli, P. F.; Cameron, C. E.

2008-12-01

72

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.

73

VOLInSAR-PF, the InSAR Volcano Observatory Service at Piton de la Fournaise Volcano (La Reunion Island).  

NASA Astrophysics Data System (ADS)

Since 2003, we carry out a systematic InSAR survey of the Piton de la Fournaise volcano, Reunion Island, in the framework of an AO-ENVISAT project. Since 2005 this activity gets the status of Observatory Service of the Observatoire de Physique du Globe de Clermont-Ferrand (OPGC). From 375 ASAR images acquired between 2003 and 2010, we have produced more than 2100 interferograms that allowed us to map the deformations related to 21 eruptions and thus to better understand the internal processes acting during each eruption. In the same time, we have developed an automatic procedure to provide full resolution interferograms, trough a dedicated WEB site, to the Volcano Observatory of Piton de la Fournaise (OVPF), and our other partners, within a few hours after receiving the ASAR images. In this way, our work is a first step toward an operational system of InSAR monitoring of volcanic activity. Since the beginning of 2010, the VOLInSAR-PF database is also open to the entire community, trough an anonymous login that gives access to slightly reduced resolution interferograms. We will present the VOLInSAR-PF database, the main results it provides concerning the way Piton de la Fournaise is deforming, and the main perspectives for monitoring provided by the new InSAR data (PALSAR-ALOS, TerraSAR-X, RADARSAT-2, COSMO-Skymed) we are beginning to integrate in the database.

Froger, Jean-Luc; Cayol, Valérie; Augier, Aurélien; Souriot, Thierry

2010-05-01

74

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.

75

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

76

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

Microsoft Academic Search

Waveform inversions of the very-long-period components of the seismic wavefield produced by an explosive eruption that occurred on 11 January, 2006 at Augustine Volcano, Alaska constrain the seismic source location to near sea level beneath the summit of the volcano. The calculated moment tensors indicate the presence of a volumetric source mechanism. Systematic reconstruction of the source mechanism shows the

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

2011-01-01

77

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

78

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

79

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

80

Rockfalls at Augustine Volcano, Alaska: 2003-2006  

Microsoft Academic Search

Rockfalls, avalanches and landslides have been frequently recorded in seismic data at Augustine Volcano for many years. Typical years such as 2003 or 2004 had several dozen such events that were strong enough to trigger the automatic event detection system. Typical events lasted about 30 sec, had frequencies >6 Hz, and were strongest on summit stations, suggesting that they were

N. Deroin; S. R. McNutt; C. Reyes; D. Sentman

2007-01-01

81

Granulite facies xenoliths from Prindle volcano, Alaska: Implications for the northern Cordilleran crustal lithosphere  

Microsoft Academic Search

Xenoliths collected from Prindle volcano, Alaska (Lat. 63.72°N; Long. 141.82°W) provide a unique opportunity to examine the lower crust of the northern Canadian Cordillera. The cone's pyroclastic deposits contain crustal and mantle-derived xenoliths. The crustal xenoliths include granulite facies metamorphic rocks and charnockites, comprising orthopyroxene (opx)–plagioclase (pl)–quartz (qtz)±mesoperthite (msp) and clinopyroxene (cpx). Opx–cpx geothermometry yields equilibrium temperatures (T) from 770

Edward D. Ghent; Benjamin R. Edwards; J. K. Russell; James Mortensen

2008-01-01

82

Quenched mafic inclusions in ?2200 years B.P. deposits at Augustine Volcano, Alaska  

Microsoft Academic Search

This article describes results from morphological, textural, mineralogical, and compositional analyses of lava clasts and quenched mafic inclusions from 10 Holocene debris-avalanche deposits (2200–125 years B.P.) that form the lower flanks of Augustine Volcano, Alaska. Mafic inclusions collected from the Rocky Point pyroclastic-flow deposit emplaced during the 2006 eruption are included for comparison. All deposits contain evidence for mixing between

Arron R. Steiner; Brandon L. Browne; Christopher J. Nye

2011-01-01

83

Quenched mafic inclusions in ?2200 years B.P. deposits at Augustine Volcano, Alaska  

Microsoft Academic Search

This article describes results from morphological, textural, mineralogical, and compositional analyses of lava clasts and quenched mafic inclusions from 10 Holocene debris-avalanche deposits (2200–125 years B.P.) that form the lower flanks of Augustine Volcano, Alaska. Mafic inclusions collected from the Rocky Point pyroclastic-flow deposit emplaced during the 2006 eruption are included for comparison. All deposits contain evidence for mixing between

Arron R. Steiner; Brandon L. Browne; Christopher J. Nye

2012-01-01

84

A Parametric Study of the Explosive Eruptions of Augustine Volcano, Alaska, January 11- 28, 2006  

Microsoft Academic Search

A series of 13 explosive eruptions occurred at Augustine Volcano, Alaska, from January 11-28, 2006. Each of these lasted 2.5 to 19 minutes and produced ash columns 3-14 km high. We investigated a number of parameters to determine systematic trends, including durations, seismic amplitudes, frequency contents, signal characteristics, peak acoustic pressures, ash column heights, and lengths of pre-event and post-event

S. Estes; S. R. McNutt; S. Stihler; S. de Angelis; T. Petersen

2006-01-01

85

Airborne Measurements of Gas Emissions during the 2009 Eruption of Redoubt Volcano, Alaska  

Microsoft Academic Search

Multi-component measurements of gas emissions were critical for assessing volcanic processes and thus hazard prior to and during the eruption of Redoubt Volcano, Alaska, which began in March 2009. Carbon dioxide (CO2) emissions were elevated at least six months prior to the onset of the eruption, with emission rates on the order of 1,800 tonnes per day (t\\/d) in October

C. A. Werner; P. J. Kelly; M. P. Doukas; M. A. Pfeffer; W. C. Evans; R. G. McGimsey; C. A. Neal

2009-01-01

86

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

87

Lawrence Livermore Laboratory (LLL) gravity work for the Hawaiian Volcano Observatory  

SciTech Connect

The objective of this funding has been to install two modified UCSD superconducting gravimeters at the Hawaiian Volcano Observatory (HVO). The research and development underlying the modifications was funded primarily by NOAA and in smaller part by this contract. Modification and installation of the instruments at HVO could not proceed prior to completion of this effort. Although considerable work remains to be done to guarantee optimum performance of all future instruments, three instruments have been assembled using present technology and their performance meets our most optimistic expectations. No instrumental drift has been measurable on them and current results allow us to set an upper limit on drift at about 0.5 {mu}Gal for a five month record at Miami. As longer simultaneous records from two instruments are obtained this limit will be set lower. They reveal substantial gravity variations due to rainfall as well as smaller ones which may be caused by activity within the volcano. 2 refs., 1 fig.

Goodkind, J.M.

1990-05-05

88

High-precision earthquake location, velocity determination, and event family identification at Augustine Volcano, Alaska, from 1993 through the 2005-2006 eruption  

NASA Astrophysics Data System (ADS)

Volcano seismic networks typically have few stations and marginal coverage, providing challenges for earthquake location in a complex, three-dimensional setting. To improve location precision at Augustine Volcano, Alaska, we compute a three-dimensional P-wave velocity model using double-difference (DD) tomography combined with waveform cross-correlation (WCC) techniques. We also examine temporal changes in earthquake locations and waveform characteristics associated with the 2005-2006 eruption and pre-eruptive seismicity. The Alaska Volcano Observatory (AVO) has monitored Augustine using up to 9 stations since 1993, and the AVO hypocenter and waveform catalog from 1993-2006 serves as the initial dataset. Many of the catalog hypocenters locate above the summit, reflecting the limitations of applying standard location techniques in rugged and sparsely instrumented volcanic settings. WCC using bispectrum verification improves the pick accuracy of the catalog data and is used to identify similar earthquakes. Waveform similarity at Augustine is low compared to other Alaskan volcanoes such as Redoubt, and most event families contain less than 100 events. Earthquakes recorded during a period of increasing pre-eruptive seismicity in December 2005 form clusters of similar earthquakes over periods of days. Events prior to the 2005-2006 eruption can exhibit a high degree of similarity over multiple years. The DD tomography method provides significantly improved absolute and relative earthquake locations and source region velocity information. We use differential travel times from catalog and cross-correlation data to simultaneously invert for hypocenter location and P-wave velocity structure. Previous studies have shown a high degree of north-south trending variation in compressional wave velocity at Augustine. This is reflected in severe station correction-velocity-depth tradeoffs when performing standard 1D inversions to solve for a starting model. Using our combined DD tomography and WCC approach, we better constrain the 3D nature of velocity heterogeneity beneath the volcano.

Deshon, H. R.; Prejean, S. G.; Thurber, C. H.; Power, J. A.

2006-12-01

89

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

90

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

Microsoft Academic Search

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

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

2006-01-01

91

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

92

U. S. Geological Survey Volcano Hazards Program  

NSDL National Science Digital Library

A comprehensive overview of the U.S. Geological Survey's Volcano Hazards Program and current volcanic activity in the United States. The Volcano Hazards Program monitors volcanoes and collects the best possible scientific information on volcanoes in the United States and elsewhere to reduce the risk from volcanic activity. Site includes links to the Program's four volcano observatories in Alaska, the Cascades (Washington State) , Hawaii, and Long Valley (California). Other links include information on volcano hazards: types, effects, locations and historical eruptions, information on reducing volcanic risks, volcano monitoring, emergency planning, and warning schemes. Other resources available are a photoglossary, volcano fact sheets and videos, an educator's page, and updates and weekly reports on worldwide, U.S., and Russian volcano activity.

93

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

Microsoft Academic Search

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

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

2010-01-01

94

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

95

Velocity Structure and 2008 Eruptive Seismicity 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, and most recently erupted in 2008. We present updated results from Okmok seismicity between January 2003 and May 2009. The volcanic caldera has been well instrumented with a network of as many as nine short-period and four broadband seismometers, providing good azimuthal coverage. Since the 2008 eruption, the volcano underwent a period of increased seismicity (addition of over 700 earthquakes) making earthquake tomography more feasible. Using a combination of waveform cross-correlation and double-difference seismic tomography, we derive refined Vp and Vs models, relocate hypocenters in them, and carry out resolution tests on the models. We image two low Vp and Vs anomalies: one directly beneath the caldera extending to 4-5 km below sea level and another to the southwest below a well known geothermal area. In addition, we re-calculate focal mechanisms in the updated model for relocated events prior to and during the 2008 eruption. We observe high focal mechanism diversity, including many reverse-faulting events. Finally, we present the 2008 relocation results in the context of satellite ash observations and seismic tremor for a detailed assessment of Okmok's seismic activity during vent formation and stabilization. The earthquakes accompanying the onset of the eruption occurred in a vertical lineation at about 4 km below sea level to the northwest of Cone D, directly below the site of the new vent, and spread slightly towards the east and west over the next few hours. Four hours after the first earthquakes, a sequence of events began near sea level. As the eruption progressed, events expanded both to greater depths and outward throughout the caldera volume, mainly westward in the direction of Cone A. The shallower and deeper groups of events seen in the early eruption remained separated by a nearly aseismic region.

Ohlendorf, S. J.; Thurber, C. H.; Prejean, S. G.

2010-12-01

96

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

Microsoft Academic Search

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

E. E. Daley; S. E. Swanson

1985-01-01

97

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

Microsoft Academic Search

Augustine Volcano, Cook Inlet, Alaska, is a subduction-related Aleutian arc volcano located approximately 275 km southwest of Anchorage. During the past 200 years, Augustine volcano has shown explosive eruptive behavior seven times, with the most recent activity occurring in January through March 2006. Its ash and pumice eruptions pose a threat to commercial air traffic, the local fishing industry, and

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

2006-01-01

98

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

NASA Astrophysics Data System (ADS)

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 Radar (SAR) images acquired from three descending and three ascending satellite tracks. Multiple interferograms were stacked to detect the average deformation rate while reducing the effect of changes in atmospheric condition. To retrieve a temporal deformation sequence, we applied the Least-Squares method and Singular Value Decomposition method to a set of multiple-temporal interferograms. Interferograms before 2006 show about 3 cm/year subsidence, probably caused by the contraction and compaction of pyroclastic flow deposits from the 1986 eruption; no significant (i.e., larger than 2 cm) precursory inflation associated with the 2006 eruption was observed. After the January 2006 eruption, we detect rapid subsidence over the area of the 2006 pyroclastic flow deposits. The observed deformation from satellite radar interferometry agrees with the measurement from the Global Positioning System (GPS) network. This study demonstrates that satellite radar interferometry can be used to study the deformation of Augustine volcano to help understand the magma plumbing system and the characteristics of pyroclastic flows.

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

2006-12-01

99

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

100

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

National Technical Information Service (NTIS)

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 environ...

R. P. Hoblitt T. R. Orr

2008-01-01

101

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

102

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

103

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

NASA Astrophysics Data System (ADS)

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

Sanchez-Aguilar, John Jairo

104

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

105

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

106

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

NASA Astrophysics Data System (ADS)

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.

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

2008-05-01

107

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

108

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

109

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

Microsoft Academic Search

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

R. P. Hoblitt; D. J. Schneider

2009-01-01

110

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

Microsoft Academic Search

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

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

2006-01-01

111

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

112

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

113

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

114

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

115

Volcanoes.  

ERIC Educational Resources Information Center

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

Tilling, Robert I.

116

Volcanoes.  

ERIC Educational Resources Information Center

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

Tilling, Robert I.

117

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

118

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

Microsoft Academic Search

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

Zhong Lu; Timothy Masterlark; Daniel Dzurisin

2005-01-01

119

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

Microsoft Academic Search

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

Zhong Lu; Timothy Masterlark; Daniel Dzurisin

2005-01-01

120

Local infrasound observations of large ash explosions at Augustine Volcano, Alaska, during January 11-28, 2006  

Microsoft Academic Search

We present and interpret acoustic waveforms associated with a sequence of large explosion events that occurred during the initial stages of the 2006 eruption of Augustine Volcano, Alaska. During January 11-28, 2006, 13 large explosion events created ash-rich plumes that reached up to 14 km a.s.l., and generated atmospheric pressure waves that were recorded on scale by a microphone located

Tanja Petersen; Silvio De Angelis; Guy Tytgat; Stephen R. McNutt

2006-01-01

121

Local infrasound observations of large ash explosions at Augustine Volcano, Alaska, during January 11–28, 2006  

Microsoft Academic Search

We present and interpret acoustic waveforms associated with a sequence of large explosion events that occurred during the initial stages of the 2006 eruption of Augustine Volcano, Alaska. During January 11–28, 2006, 13 large explosion events created ash-rich plumes that reached up to 14 km a.s.l., and generated atmospheric pressure waves that were recorded on scale by a microphone located

Tanja Petersen; Silvio De Angelis; Guy Tytgat; Stephen R. McNutt

2006-01-01

122

Estimates of eruption velocity and plume height from infrasonic recordings of the 2006 eruption of Augustine Volcano, Alaska  

Microsoft Academic Search

The 2006 eruption of Augustine Volcano, Alaska, began with an explosive phase comprising 13 discrete Vulcanian blasts. These events generated ash plumes reaching heights of 3–14km. The eruption was recorded by a dense geophysical network including a pressure sensor located 3.2km from the vent. Infrasonic signals recorded in association with the eruptions have maximum pressures ranging from 13–111Pa. Eruption durations

Jacqueline Caplan-Auerbach; Anna Bellesiles; Jennifer K. Fernandes

2010-01-01

123

Two Millennia of Edifice Instability at Augustine Volcano, Alaska and Implications for Future Collapse  

NASA Astrophysics Data System (ADS)

Augustine volcano, a ca. 1250-m-high lava-dome complex in the southern Cook Inlet, Alaska, has collapsed repeatedly during the late Holocene, producing debris-avalanche deposits that ring the island and extend offshore. About a dozen collapses have occurred in the past 2.2 ka, producing the highest-known collapse frequency (ca. 150-200 yr) at any volcano. Most debris avalanches at Augustine had volumes between 0.1 and 1 cu. km and reached about 7-10 km from the summit; typically about half that distance involved submarine travel into Cook Inlet. The most recent collapse took place in October 1883, forming the Burr Point debris- avalanche deposit on the north side of the volcano. Emplacement of the avalanche extended the shoreline about 2 km and produced a tsunami that impacted English Bay on the Kenai Peninsula. The collapse was accompanied by pumiceous pyroclastic flows that reached the sea and a subplinian explosive eruption that deposited ash across Cook Inlet. An earlier NW-flank collapse about 300 years ago was preceded by one of the largest known Augustine debris avalanches about 1540 +/- 110 AD. This collapse formed a new 2 x 3.5 km wide island (West Island) off the WNW coast of Augustine Island and was accompanied by a lateral blast that overrode the avalanche deposit and extended out to sea. The margins of West Island display extensive tsunami modification. Debris avalanches older than 1 ka were concentrated on the southern and eastern flanks of the volcano. Documented magmatic eruptions have accompanied several edifice-collapse events at Augustine, although syn-eruptive collapse has not been confirmed in all cases. The small size of the volcano and high magma production rates (0.0025 cu. km/yr) result in rapid reconstruction of the volcano after each collapse. The repeated cycles of collapse and regrowth have produced a subaerial and submarine apron of debris-avalanche, pyroclastic-flow, and other volcaniclastic deposits several times the volume of the edifice itself. The orientation of previous collapses shows a crude pattern of clockwise migration beginning on the east side. This may in part reflect the influence of the prior failure plane on collapse direction. Although future collapse is possible in any direction, the pattern of past collapses suggests that an elevated risk may exist for a future edifice failure to the northeast. The highest tsunami hazard exists from debris avalanches directed to the northeast, east, and south, where the shoreline lies only about 3.5-4.5 km from the summit. Risk to populated areas is contingent on factors including debris avalanche dynamics, thickness, volume, and emplacement direction, as well as timing with respect to Cook Inlet tides.

Siebert, L.; Beget, J.

2006-12-01

124

Volcanoes  

NSDL National Science Digital Library

Volcanoes is part of an online series of modules entitled Exploring the Environment. Emphasizing an integrated approach to environmental Earth Science education through problem based-learning, this module asks students to look at four different situations involving volcanoes, research the situations, and make decisions about them. Information about the three volcanic areas under exploration (Mt. Hood, Kilauea, and Yellowstone) is given through maps, movies, and videos. Additional information covers plate tectonics, locations of volcanoes, volcano monitoring and hazards, how to deal with volcano threats, lavas, eruption types, and risk analysis. Once students have gone through the information, they make real-life decisions about building near volcanoes, and the possibility of eruptions in the near future. There are teacher resources, a reference for problem-based learning, and links for more information.

125

Operational use of InSAR for volcano observatories : experience from Montserrat  

Microsoft Academic Search

Volcanoes as targets for InSAR vary greatly in the quality of their returned phase signal. There are two end-member volcano types from this perspective. Basaltic, low-relief shield volcanoes with frequent effusive eruptions and shallow magma reservoirs generally give excellent coherence and large magnitude ground deformations (~1m) that can be easily detected and modelled. However, their individual (lava flow) deposits tend

G. Wadge; B. Scheuchl; L. Cabey; M. D. Palmer; C. Riley; A. Smith; N. F. Stevens

126

Volcanoes  

NSDL National Science Digital Library

Students investigate the processes that build volcanoes, the factors that influence different eruption types, and the threats volcanoes pose to their surrounding communities. They use what they have learned to identify physical features and eruption types of several actual volcanic episodes.

Foundation, Wgbh E.

2005-12-17

127

Infrasonic Wave Observations of the January 2006 Augustine Volcano Eruptions  

Microsoft Academic Search

The recent Augustine eruptions, from the 11th to the 28th of January 2006, have produced a series of ten infrasonic signals observed at the I53US array*. The eruption times for the signals were provided by the Alaska Volcano Observatory at UAF using a Chaparral microphone present on Augustine Island a few kilometers from the crater. The bearing and distance of

J. V. Olson; C. R. Wilson; S. McNutt; G. Tytgat

2006-01-01

128

Perennial Snow and Ice Volumes on Iliamna Volcano, Alaska, Estimated with Ice Radar and Volume Modeling.  

National Technical Information Service (NTIS)

The volume of four of the largest glaciers on Iliamna Volcano was estimated using the volume model developed for evaluating glacier volumes on Redoubt Volcano. The volume model is controlled by simulated valley cross sections that are constructed by fitti...

D. C. Trabant

1999-01-01

129

The 1883 and late-prehistoric eruptions of Augustine volcano, Alaska  

Microsoft Academic Search

The eruptive history of Augustine volcano has been characterized by cycles of growth and destruction of the volcano. Repeated failure of 5 – 10% of the edifice has produced mobile debris avalanches that reached the sea on all sides. High lava extrusion rates rapidly restore the volcano to its pre-failure configuration. This equilibrium between constructive and destructive processes has resulted

Lee Siebert; James E. Begét; Harry Glicken

1995-01-01

130

High-precision earthquake location, velocity determination, and event family identification at Augustine Volcano, Alaska, from 1993 through the 2005-2006 eruption  

Microsoft Academic Search

Volcano seismic networks typically have few stations and marginal coverage, providing challenges for earthquake location in a complex, three-dimensional setting. To improve location precision at Augustine Volcano, Alaska, we compute a three-dimensional P-wave velocity model using double-difference (DD) tomography combined with waveform cross-correlation (WCC) techniques. We also examine temporal changes in earthquake locations and waveform characteristics associated with the 2005-2006

H. R. Deshon; S. G. Prejean; C. H. Thurber; J. A. Power

2006-01-01

131

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.

132

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

NASA Astrophysics Data System (ADS)

Shrub mud volcano, one of three in the Klawasi group on the eastern flank of Mount Drum volcano in the Wrangell volcanic field of eastern Alaska, has been erupting warm, saline mud and CO2-rich gas continuously since at least the summer of 1997, following 40 years of repose. The initial eruption in early summer of 1997, documented by Richter and others (1998), involved violent fountaining of mud, up to 6-8 m high, from nearly a dozen vents located near the summit, and quiet effusion from vents located about mid-way down the north flank of the 100-m-high cone. Guided by topography, early emissions of copious amounts of CO2 gas flowed in narrow streams through brushy foliage leaving behind stripes of brown, dead vegetation along the flow paths. The hazard posed by the CO2 emissions was evident from dead birds and mammals found near the vents. Initial surveys of the activity in 1997 recorded water temperatures up to 46°C. A survey in 1999 by Sorey and others (2000) found numerous active vents-many in different locations than those two years earlier-a maximum water temperature of 54°C, and an estimated total discharge of warm water of 50 l/s. Measured CO2 emissions were extrapolated to a discharge rate of 6-12 tonnes/day. The highest water temperature recorded was 57.3°C in 2000, with temperatures gradually declining since. From year to year, we found that eruptive activity migrated amongst clusters of vents, some new and some continuing from 1997. Between the summer of 2003 and the spring of 2004, the system changed dramatically when a large collapse pit formed a few tens of meters from the main summit vents and all previously active vents became inactive. This water-filled circular pit measured 28 m in diameter, up to 9 m deep, and encompassed an area that had previously been unaffected by the eruptive activity. In July 2004, water temperature and discharge at the outlet channel was 37.2°C and 9.4 l/s, respectively. The total CO2 discharge from the roiling pool was 140 l/s (about 20 tonnes/day), and the diffuse efflux (0.13 tonnes/day) was comparable to the 0.23 tonnes/day measured in 1999. Based on discharge and ?13C values of the gas and water phases (-4.6‰ and +1.35‰, respectively) carbon in the reservoir was calculated to be -3.1‰, supporting a mixed magmatic and limestone source for the CO2. Deep pits exposed during the current eruption have provided clues to the possible origin of Shrub, the largest, and highest mud volcano of the Klawasi group. Shrub stands about 100 m high and is an oblong cone in shape. Cross-sections of the material composing the cone reveal a chaotic pile of debris ranging from clay to boulders (angular to subrounded, up to 1.5 m across), the latter too large to have been rafted up by mud and gas venting. Pleistocene glaciers extending into the Copper River Valley from Mount Drum covered the area currently occupied by Shrub. We hypothesize that as the glaciers stagnated and began to retreat, subglacial melting caused by the rising warm mud formed an anomalous moulin that became the receptacle for rock and sediment debris washed in from supraglacier runoff. Thus the constructional form of Shrub is likely a moulin kame.

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

2007-12-01

133

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

Microsoft Academic Search

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

Michael A. Fisher; Natalia A. Ruppert; Randall A. White; Frederic H. Wilson; Drew Comer; Ray W. Sliter; Florence L. Wong

2009-01-01

134

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  

Microsoft Academic Search

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

M. L. Vitale; B. L. Browne

2010-01-01

135

Pre-Eruptive Exsolution of Chlorine-Enriched Volatile Phases at Augustine Volcano, Alaska: Evidence from Silicate Melt Inclusions and Cl Solubility Modeling  

Microsoft Academic Search

Augustine volcano has experienced 6 explosive eruptions in historic time and is located in Cook Inlet, Alaska, approximately 330 km from Anchorage. Most lavas and tephra range from primitive andesite to dacite, but minor basalt flows crop out on the island. The matrix and silicate melt inclusion glasses are more felsic, however. Volcanic gases collected from the Augustine crater during

J. D. Webster; C. Tappen; C. Mandeville; C. Harms

2003-01-01

136

Volcanoes as possible indicators of tectonic stress orientation — Aleutians and Alaska  

Microsoft Academic Search

A new method for obtaining from volcanic surface features the orientations of the principal tectonic stresses is applied to Aleutian and Alaskan volcanoes. The underlying concept for this method is that flank eruptions for polygenetic volcanoes can be regarded as the result of a large-scale natural magmafracturing experiment. The method essentially relies on the recognition of the preferred orientation of

Kazuaki Nakamura; Klaus H. Jacob; John N. Davies

1977-01-01

137

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

PubMed

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

DORAVA; MILNER

1999-02-01

138

In Brief: Russian volcano warnings reinstated  

NASA Astrophysics Data System (ADS)

The Kamchatka Volcanic Eruption Response Team (KVERT) is again issuing warnings for aviation during periods of activity by Kamchatkan volcanoes. KVERT had stopped issuing warnings on 1 March due to a loss of funding by the Federal Unitary Enterprise State Air Traffic Management Corporation of Russia (see Eos 88(12), 2007). The funding for this work has now resumed. KVERT is a collaborative project of scientists from the Russian Institute of Volcanology and Seismology, the Kamchatka Experimental and Methodical Seismological Department, and the Alaska Volcano Observatory.

Zielinski, Sarah

2007-04-01

139

Volcano  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on volcanoes and the destruction that results from eruptions. Students are given a scenario of massive volcanic destruction and have to come up with a plan to help those affected by the events. 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

140

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

141

A Parametric Study of the Explosive Eruptions of Augustine Volcano, Alaska, January 11- 28, 2006  

NASA Astrophysics Data System (ADS)

A series of 13 explosive eruptions occurred at Augustine Volcano, Alaska, from January 11-28, 2006. Each of these lasted 2.5 to 19 minutes and produced ash columns 3-14 km high. We investigated a number of parameters to determine systematic trends, including durations, seismic amplitudes, frequency contents, signal characteristics, peak acoustic pressures, ash column heights, and lengths of pre-event and post-event quiescence. At the time of this writing we do not know individual tephra volumes for the various eruptions. In general, we find few strong correlations in the data set. For example, there is no clear correlation between acoustic peak pressure and ash column height, or between seismic amplitude and duration. Thus it is difficult to give a simple number or ratio to characterize the explosive eruptions. However, several events stand out as being end members in their attributes. Two events (11 January 13:44 UT and 28 January 08:37 UT) are short (180 and 140 sec respectively) and have very impulsive and high acoustic peak pressures of 93 and 105 Pa, as well as high seismic amplitudes. We interpret these to be mainly gas releases, although some tephra was erupted. Two of the largest events followed quiescent intervals of 2 days or longer: 16 January 16:58 UT, and 28 January 05:24 UT. These two events had reduced displacements (DR) of 13.9 and 13.3 cm2 respectively, larger than all others except the two gas release events cited above. While these DR values are typical for eruptions with ash columns to 9-14 km, most other DR values of 3.3 to 5.8 cm2 are low for the 8-11 km ash column heights observed. The combination of short durations, small DR and high ash columns suggests that these events are more explosive than most other eruptions, in agreement with the vulcanian eruption type. Several events had long durations on individual seismic stations but not on others; we interpret these to represent pyroclastic flows passing near the affected stations so that fallout of material from the cloud adds energy to the ground only near those stations. The eruption on 28 January 05:24 UT had abundant lightning, whereas two others that followed (28 January 11:04 UT and 16:42 UT) had no lightning. The 05:24 UT eruption had a much longer duration (1180 sec compared to less than 460 sec for the others), a slightly higher ash column height (9 vs. 8 km) and higher acoustic peak pressure (83 vs. 66 and 24 Pa). The data suggest that the lightning-rich 05:24 UT eruption produced more tephra than the following eruptions, hence there were more charge carriers available. The parametric data outlined here are most useful when combined with other data to address specific research questions. Caution should be exercised in using such data to estimate eruption conditions in near-real time.

Estes, S.; McNutt, S. R.; Stihler, S.; de Angelis, S.; Petersen, T.

2006-12-01

142

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

143

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

USGS Publications Warehouse

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

Trabant, Dennis C.

1999-01-01

144

The resource and development potential of the Makushin Volcano geothermal reservoir of the Aleutian Islands, Alaska  

SciTech Connect

Geological, geophysical, geochemical, and well flow-test data suggest a 13+- km/sup 3/ bulk volume, water-dominated, 195/sup 0/C geothermal reservoir that reaches a depth of 4.4+- km beneath the Makushin Volcano caldera. Through numerous fractures, this reservoir is presently discharging gases on the northern, eastern, and southern flanks of the volcano, as indicated by the occurrence of numerous fumaroles. Rising gases are also escaping directly to the surface through the caldera, as reflected by the largest fumarole field on the summit caldera.

Reeder, J.W.; Denig-Chakroff, D.N.; Economides, M.J.

1987-03-01

145

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

146

Seismic swarm associated with the 2008 eruption of Kasatochi Volcano, Alaska: Earthquake locations and source parameters  

Microsoft Academic Search

An energetic seismic swarm accompanied an eruption of Kasatochi Volcano in the central Aleutian volcanic arc in August of 2008. In retrospect, the first earthquakes in the swarm were detected about 1 month prior to the eruption onset. Activity in the swarm quickly intensified less than 48 h prior to the first large explosion and subsequently subsided with decline of

Natalia A. Ruppert; Stephanie Prejean; Roger A. Hansen

2011-01-01

147

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

Microsoft Academic Search

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

M. Burgy; D. K. Bolton

2006-01-01

148

Petrologic study of lavas and pyroclasts from the 2006 eruption of Augustine Volcano, Alaska  

Microsoft Academic Search

Pyroclastic-flow deposits, block-and-ash flow deposits, and lava flows produced during the mid-January through March 2006 eruption of Augustine Volcano contain several distinct juvenile lithologies: 56-57 wt. % SiO2, porphyritic andesite with distinct olive green rinds (\\

M. R. Tilman; J. F. Larsen; M. L. Coombs; C. J. Nye

2006-01-01

149

Estimation of tsunami hazard from volcanic activity — Suggested methodology with Augustine volcano, Alaska as an example  

Microsoft Academic Search

A general approach for the estimation of tsunami height and hazard in the vicinity of active volcanoes has been developed. An empirical relationship has been developed to estimate the height of the tsunami generated for an eruption of a given size. This relationship can be used to estimate the tsunami hazard based on the frequency of eruptive activity of a

Hemendra Acharya

1989-01-01

150

CONFIRMATION AND CALIBRATION OF COMPUTER MODELING OF TSUNAMIS PRODUCED BY AUGUSTINE VOLCANO, ALASKA  

Microsoft Academic Search

Numerical modeling has been used to calculate the characteristics of a tsunami generated by a landslide into Cook Inlet from Augustine Volcano. The modeling predicts travel times of ca. 50-75 minutes to the nearest populated areas, and indicates that significant wave amplification occurs near Mt. Iliamna on the western side of Cook Inlet, and near the Nanwelak and the Homer-Anchor

James E. Beget; Zygmunt Kowalik

2006-01-01

151

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

Microsoft Academic Search

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

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

2006-01-01

152

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

USGS Publications Warehouse

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

Trabant, Dennis C.; Hawkins, Daniel B.

1997-01-01

153

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

Microsoft Academic Search

Geochemical and textural features of whole-rock samples, phenocrysts, matrix glasses, and silicate melt inclusions from five prehistoric pumiceous tephra units of Augustine volcano, Alaska, were investigated to interpret processes of magma storage and evolution. The bulk-rock compositions of the tephra (designated G, erupted ca. 2100 a.B.P.; I ca. 1700 a.B.P.; H ca. 1400 a.B.P.; and C1 and C2 ca. 1000 a.B.P.) are silicic andesite;

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

2009-01-01

154

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

Microsoft Academic Search

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

Timothy Masterlark; Zhong Lu; Russell Rykhus

2006-01-01

155

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

156

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

157

Lightning Mapping Observations of the 2006 Eruption of Augustine Volcano, Alaska  

Microsoft Academic Search

In January of 2006 Mt. Augustine erupted explosively producing ash plumes that often exceeded 9 km in altitude. A small Lightning Mapping Array was deployed east of Mt. Augustine in Alaska and was in operation for the eruption on January 28, 2006. Our observations show a lightning sequence in the volcanic plume (called the plume phase), which began approximately ten

S. A. Behnke; R. J. Thomas; P. R. Krehbiel; W. Rison; H. E. Edens; S. R. McNutt

2008-01-01

158

The 1997 Eruption of Okmok Volcano, Alaska, a Synthesis of Remotely Sensed Data  

Microsoft Academic Search

Okmok Volcano in the central Aleutian Islands erupted in February of 1997. The eruption produced a lava flow in the central caldera over 5.5 x107 m3 in volume over 7.5 km2. This caldera is the most active of the Aleutian Arc, and is now the focus of international multidisciplinary studies. A synthesis of remotely sensed data (AIRSAR, derived DEMs, Landsat

L. Moxey; J. Dehn; K. Papp; M. Patrick; R. Guritz

2001-01-01

159

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

Microsoft Academic Search

On 4 March 1999, a shallow ML 5.2 earthquake occurred beneath Unimak Island in the Aleutian Arc. This earthquake was located 10-15 km west of Shishaldin Volcano, a large, frequently active basaltic-andesite stratovolcano. A Strombolian eruption began at Shishaldin roughly 1 month after the mainshock, culminating in a large explosive eruption on 19 April. We address the question of whether

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

2002-01-01

160

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

Microsoft Academic Search

Two large lahars with volumes of 0.4-0.6 km3 and several smaller lahars with volumes of 0.05-0.1 km3 inundated the Drift River valley on the north flank of Redoubt Volcano during its 2009 eruption. Significant lahars were produced on March 22-23 during the initial explosive phase of the eruption following about 8 months of precursory unrest that included increased fumarolic melting

C. F. Waythomas

2010-01-01

161

Timing, distribution, and character of proximal products of the 2006 eruption of Augustine Volcano, Alaska  

Microsoft Academic Search

During and after the 2006 eruption of ~1250-m-high Augustine Volcano, we compiled a geologic map and chronology of new deposits using observational flights, oblique and aerial photography, infrared imaging, satellite data, and field investigations. The main phase of the eruption commenced with two explosions on January 11 that produced ash plumes and snow-rich avalanches that reached down to ~600 m

M. L. Coombs; K. F. Bull; C. J. Nye; D. J. Schneider; J. W. Vallance; R. Wessels

2006-01-01

162

Seismicity of Block-and-Ash Flows Occurring During the 2006 Eruption of Augustine Volcano, Alaska  

Microsoft Academic Search

In January 2006, Augustine Volcano began erupting following an increase in seismicity that was first noted in late April 2005. Thirteen large explosive eruptions of Augustine occurred from January 11 to 28, 2006, followed by a continuously erupting phase and then by a dome growth phase in which numerous pyroclastic flows and block-and-ash flows occurred. As a new steep-sided and

Nicole DeRoin; Stephen R. McNutt; Davis D. Sentman; Celso Reyes

163

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.

164

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

NASA Astrophysics Data System (ADS)

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

2011-03-01

165

Unusual ice diamicts emplaced during the December 15, 1989 eruption of redoubt volcano, Alaska  

USGS Publications Warehouse

Ice diamict comprising clasts of glacier ice and subordinate rock debris in a matrix of ice (snow) grains, coarse ash, and frozen pore water was deposited during the eruption of Redoubt Volcano on December 15, 1989. Rounded clasts of glacier ice and snowpack are as large as 2.5 m, clasts of Redoubt andesite and basement crystalline rocks reach 1 m, and tabular clasts of entrained snowpack are as long as 10 m. Ice diamict was deposited on both the north and south volcano flanks. On Redoubt's north flank along the east side of Drift piedmont glacier and outwash valley, ice diamict accumulated as at least 3 units, each 1-5 m thick. Two ice-diamict layers underlie a pumice-lithic fall tephra that accumulated on December 15 from 10:15 to 11:45 AST. A third ice diamict overlies the pumiceous tephra. Some of the ice diamicts have a basal 'ice-sandstone' layer. The north side icy flows reached as far as 14 km laterally over an altitude drop of 2.3 km and covered an area of about 5.7 km2. On Crescent Glacier on the south volcano flank, a composite ice diamict is locally as thick as 20 m. It travelled 4.3 km over an altitude drop of 1.7 km, covering about 1 km2. The much higher mobility of the northside flows was influenced by their much higher water contents than the southside flow(s). Erupting hot juvenile andesite triggered and turbulently mixed with snow avalanches at snow-covered glacier heads. These flows rapidly entrained more snow, firn, and ice blocks from the crevassed glacier. On the north flank, a trailing watery phase of each ice-diamict flow swept over and terraced the new icy deposits. The last (and perhaps each) flood reworked valley-floor snowpack and swept 35 km downvalley to the sea. Ice diamict did not form during eruptions after December 15 despite intervening snowfalls. These later pyroclastic flows swept mainly over glacier ice rather than snowpack and generated laharic floods rather than snowflows. Similar flows of mixed ice grains and pyroclastic debris resulted from the November 13, 1985 eruption of Nevado del Ruiz volcano and from eruptions of snowclad Mount St. Helens in 1982-1984. Such deposits at snowclad volcanoes are initially broad and geomorphically distinct, but they soon become extensively reworked and hard to recognize in the geologic record. ?? 1994.

Waitt, R. B.; Gardner, C. A.; Pierson, T. C.; Major, J. J.; Neal, C. A.

1994-01-01

166

The 1883 and late-prehistoric eruptions of Augustine volcano, Alaska  

NASA Astrophysics Data System (ADS)

The eruptive history of Augustine volcano has been characterized by cycles of growth and destruction of the volcano. Repeated failure of 5 - 10% of the edifice has produced mobile debris avalanches that reached the sea on all sides. High lava extrusion rates rapidly restore the volcano to its pre-failure configuration. This equilibrium between constructive and destructive processes has resulted in a relatively low lava-dome complex surrounded by an apron of volcaniclastic debris three times the volume of the dome complex.The most recent edifice collapse occurred in 1883, producing the 0.3 km3 Burr Point debris-avalanche deposit. Three major slide blocks extended the shoreline up to 2 km and produced a tsunami that swept across Cook Inlet. Hummock morphologies change from a proximal radial orientation to a dominantly transverse alignment reflecting deceleration and compression of the avalanches as they enter the sea. The breached crater formed by collapse was then largely filled by a 0.09 km3 lava dome and a 0.04 km3 lava flow travelled down the north flank. Lithic block-and-ash flows and pyroclastic surges reached the coast. The Burr Point avalanche deposit partially overlaps the Rocky Point debris-avalanche deposit to the west that was probably emplaced 200-400 years B.P.A major collapse event at ca. 1540 ± 110 A.D. produced the West Island debris avalanche, ending a period of expansion of the western side of the island. An accompanying lateral blast overtopped the avalanche, covering a 40 ° sector of the west flank. The plinian tephra layer B may also have been erupted at the time of the West Island eruption.Today Augustine volcano has rebuilt itself to a size similar to that which preceded the last edifice failure in 1883. The frequency of past collapses (three in the last 500 years) suggests that summit collapse is a possibility during any future eruption. The next major collapse is expected to involve 0.1 - 0.5 km3 of the summit; the ensuing debris avalanche would likely reach the coast, producing a tsunami that could impact populated areas of the Kenai Peninsula. The largest tsunami would result from collapse in directions other than to the north or west. Tsunami magnitude is contingent on failure volume, direction and timing with respect to tides.

Siebert, Lee; Begét, James E.; Glicken, Harry

1995-07-01

167

High Rate GPS data on Augustine volcano (Alaska, USA) during the 2006 eruption  

NASA Astrophysics Data System (ADS)

Transient episodes of ground displacement related to the dynamics of magmatic fluids as possible precursors to eruptive activity can be revealed through a careful analysis of high rate GPS (HRGPS) data. In the very first phases of an eruption the real time processing of high rate GPS data can be used by civil protection authorities to monitor the opening of fractures field on the slopes of volcanoes. During eruption, large explosions, opening of vents, migration of fractures fields, landslides and other dangerous phenomena can be monitored and their potential for damage estimated. This technique has already revealed its importance during the 2002-2003 Stromboli Island (Italy) eruption (Mattia et al., GRL, 2004). In this work, we have processed the GPS data of the stations on Augustine volcano spanning from August 2005 to February 2006. The sub-daily time series of the coordinates (15 minute medians) show clear evidences of the dynamic leading to the 2006 eruption and the 15 sec. data time series of some peculiar periods, gives new insights in the fast processes acting before and during the eruption. We also show the first results of a dynamic modelling of the volcanic sources acting during this last eruption of Augustine.

Mattia, M.; Bruno, V.; Palano, D.; Marco, A.

2006-12-01

168

Timing, distribution, and character of proximal products of the 2006 eruption of Augustine Volcano, Alaska  

NASA Astrophysics Data System (ADS)

During and after the 2006 eruption of ~1250-m-high Augustine Volcano, we compiled a geologic map and chronology of new deposits using observational flights, oblique and aerial photography, infrared imaging, satellite data, and field investigations. The main phase of the eruption commenced with two explosions on January 11 that produced ash plumes and snow-rich avalanches that reached down to ~600 m elevation on all flanks. A second series of six explosions on January 13 - 14 produced ash plumes, widespread but thin pyroclastic flows on the upper flanks, and thicker, lobate pyroclastic flows that traveled down most flanks of the volcano. On January 16, we first observed a small new lava dome growing at the summit. An explosion on January 17 produced a ballistic fall deposit on the west and southwest sides of the volcano and further lobate pyroclastic flows. Flows from January 13 - 17 are rich in porphyritic, low-silica andesite (56 - 57 wt% SiO2) and contain a subordinate amount of light gray, slightly inflated, high-silica andesite (~62 wt% SiO2) with a distinct, crystalline groundmass (nicknamed `cinderblock'). Minor dense glassy clasts, most abundant in the earliest flows from the explosive phase, are likely pieces of extruded dome lava that may have reached the surface as early as January 12 based on seismicity. Lava effusion continued and by January 22, a 275 m-long, smooth andesitic lobe appeared in the east half of the summit crater. By late January, two new lobes of "cinderblock" andesite had been emplaced adjacent to this early lobe. Four explosions on January 28 heralded the onset of a four-day period of continuous eruption and generated a large apron of block and ash flow deposits on the northern flank of the island. These deposits are rich in cinderblock, poor in dark-gray porphyritic andesite, and rich in banded mixtures of cinderblock and dark-gray andesite. ASTER imagery shows that the block and ash flows had reached their maximum extent by January 31. Lava effusion throughout February and into early March was accompanied by frequent block-and-ash flows, and eventually formed a ~900-m-long lava flow that spilled out of the summit crater to the north. From March 7 to 14, extrusion increased markedly and two thick, blocky lava flow lobes moved down the north and northeast flank of the volcano. Lava effusion continued throughout March, shedding small block and ash flows and producing observable morphological changes at the volcano's summit. In April and May, three gravitational collapses from the west margin of the north lava flow produced additional block and ash flows. The lava flows and their block and ash flow apron comprise dark-gray porphyritic andesite (57 - 60 wt% SiO2) and subordinate amounts of highly crystalline, sugary low-silica andesite (56 - 57 wt% SiO2); the cinderblock high-silica andesite is absent.

Coombs, M. L.; Bull, K. F.; Nye, C. J.; Schneider, D. J.; Vallance, J. W.; Wessels, R.

2006-12-01

169

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.

170

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

NASA Astrophysics Data System (ADS)

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

Waythomas, C. F.

2010-12-01

171

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

172

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

173

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

174

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

USGS Publications Warehouse

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

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

2003-01-01

175

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

176

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

177

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

178

The Middle Scoria sequence: A Holocene violent strombolian, subplinian and phreatomagmatic eruption of Okmok volcano, Alaska  

NASA Astrophysics Data System (ADS)

The Middle Scoria deposit represents an explosive eruption of basaltic andesite magma (54 wt. % SiO2) from Okmok volcano during mid-Holocene time. The pattern of dispersal and characteristics of the ejecta indicate that the eruption opened explosively, with ash textural evidence for a limited degree of phreatomagmatism. The second phase of the eruption produced thick vesicular scoria deposits with grain texture, size and dispersal characteristics that indicate it was violent strombolian to subplinian in style. The third eruptive phase produced deposits with a shift towards grain shapes that are dense, blocky, and poorly vesicular, and intermittent surge layers, indicating later transitions between magmatic (violent strombolian) to phreatomagmatic (vulcanian) eruptive styles. Isopach maps yield bulk volume estimates that range from 0.06 to 0.43 km3, with ~ 0.04 to 0.25 km3 total DRE. The associated column heights and mass discharge values calculated from isopleth maps of individual Middle Scoria layers are 8.5 - 14 km and 0.4 to 45 × 106 kg/s. The Middle Scoria tephras are enriched in plagioclase microlites that have the textural characteristics of rapid magma ascent and relatively high degrees of effective undercooling. Those textures probably reflect the rapid magma ascent accompanying the violent strombolian and subplinian phases of the eruption. In the later stages of the eruption, the plagioclase microlite number densities decrease and textures include more tabular plagioclase, indicating a slowing of the ascent rate. The findings on the Middle Scoria are consistent with other explosive mafic eruptions, and show that outside of the two large caldera-forming eruptions, Okmok is also capable of producing violent mafic eruptions, marked by varying degrees of phreatomagmatism.

Wong, Lily J.; Larsen, Jessica F.

2009-07-01

179

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

180

Volcano survey  

Microsoft Academic Search

SummaryA short review is made of the main means of investigation of eruption forecast, used in the few existing, accurately staffed volcanological observatories as well as during sporadic expeditions on active volcanoes, together with non-exhaustive data obtained during recent years (volcanoseismology, gravimetry, tiltmetry, geodetic measurements, magnetic and aeromagnetic surveys, chemistry of gas, waters and sublimates, geochemistry). Details of research performed

H. Tazieff

1966-01-01

181

Petrologic study of lavas and pyroclasts from the 2006 eruption of Augustine Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Pyroclastic-flow deposits, block-and-ash flow deposits, and lava flows produced during the mid-January through March 2006 eruption of Augustine Volcano contain several distinct juvenile lithologies: 56-57 wt. % SiO2, porphyritic andesite with distinct olive green rinds ("green scoria"); ~62 wt. % SiO2 andesite with distinctly crystalline groundmass ("cinderblock"); dark and light grey andesites with low- to medium- SiO2 (57-60 wt. %) compositions; and banded clasts. Mid-January pyroclastic flow deposits contain predominantly green scoria; late-January pyroclastic flow deposits contain predominantly cinderblock and banded clasts with some light and dark grey andesite, and February-March lava flows and block-and-ash flows contain primarily dark grey and light grey low- to medium-SiO2 andesite. Phenocrysts in all lithologies are plagioclase, hypersthene, augite, Fe-Ti oxides, olivine, and rare amphibole, with plagioclase dominant at ~20-40 vol. % in all clasts. Four primary plagioclase textures are found in all samples: (1) euhedral plagioclase with few melt inclusions but often shot through with apatite crystals; (2) subhedral plagioclase dominated by melt inclusions and apatite crystals; (3) dominantly sieved plagioclase; and (4) plagioclase with a combination of melt inclusions and sieved texture. Banded clasts also contain skeletal plagioclase. Electron microprobe data show hypersthene and augite in the banded, cinderblock, and light grey andesite have average compositions of Wo2En65Fs32 and Wo44En41Fs14 respectively; some of the hypersthenes are rimmed with augite. The hypersthene and augite in the light grey andesite show slight zoning. Fe-Ti oxide pair compositions and calculations from the computer program QUILF indicate the green scoria oxides record temperatures of 855 to 998°C; the cinderblock andesite temperature estimates ranged from 841 to 898°C; and the banded pumice ranged from 849 to 870°C. The disequilibrium textures, the range of juvenile compositions, and the differences in equilibrium temperatures indicate at least two magmatic components present during the eruption with incomplete mingling and hybridization. Both components appear to be present throughout all phases of the eruptive activity although the relative proportions change with time. Future work will focus on phenocryst and whole rock data to test whether the high silica andesite represents a remobilization of shallow magma left from the 1986 eruption and if the low-silica andesite arrived from a deeper magma source and triggered the 2006 eruptions.

Tilman, M. R.; Larsen, J. F.; Coombs, M. L.; Nye, C. J.

2006-12-01

182

Erosion of the Barrow Environmental Observatory Coastline 2003-2008, Northern Alaska  

NASA Astrophysics Data System (ADS)

There is concern that the rate of erosion to Coastal bluffs in the arctic could increase as the duration of ice-free near shore waters also increases. The Barrow Environmental Observatory (BEO,) a coastal research reserve of 7500 acres is bounded on the east by the 11-km long Elson Lagoon shoreline. Rates of erosion to these 2 to 5 m high ice- and organic- rich permafrost bluffs have been monitored at key sites on an annual basis since 2003 as part of the Arctic Coastal Dynamics (ACD) program. Foot surveys using a survey-grade Differential Global Positioning System (DPGS) with centimeter vertical and horizontal accuracy were conducted along the entire length of the BEO coastline in August 2003, 2006 and 2007. The mean erosion rate during the 2003-06 period was 2.69 meters per year. In summer 2007, two DGPS surveys were conducted, one in June before ice breakup and the second in August late in the summer season. The June survey provides a baseline for summer 2007 measurements and will serve to document the rate of erosion between the August 2006 survey and subsequent freeze-up of Elson lagoon during the 2006-07 winter. Detailed characterization of the coastal bluff was also made in summer 2007. At every 100m along the coastal bluff, photographs of the bluff were taken and the steepness of the bluff was measured. Bathymetric measurements were collected using a high-velocity depth sounder along transects parallel and perpendicular to the coastline and up to 2km in to Elson Lagoon. Ongoing analysis is measuring the rate of erosion between each of the measurement periods and estimating the corresponding volumetric loss of bluff soil to Elson Lagoon. We are also identifying in detail, sections of coastline where the rate of erosion is differing and using these to ascertain the relative importance of offshore bathymetry, orientation of the coastline to dominant winds and the physical characteristics of the coastal bluff to the rate of erosion measured. The central goal of this paper is to report and interpret changes in inter-seasonal erosion and to update the record of long-tern erosion measurements for this section of arctic coastline.

Aguirre, A.; Brown, J.; Gaylord, A.; Tweedie, C. E.

2007-12-01

183

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

184

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

Microsoft Academic Search

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

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

2006-01-01

185

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

Microsoft Academic Search

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

Christian Huggel; Jacqueline Caplan-Auerbach; Christopher F. Waythomas; Rick L. Wessels

2007-01-01

186

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

USGS Publications Warehouse

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

Moore, H. J.

1982-01-01

187

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

ERIC Educational Resources Information Center

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

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

1996-01-01

188

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

189

Explosive eruption at Bezymianny Volcano, Russia, captured by satellite data  

NASA Astrophysics Data System (ADS)

Bezymianny (55.9°N, 160.6°E, ~2900 m elevation) is an active, explosive volcano within the Central Kamchatka Depression (CKD), Kamchatka Peninsula, Russia. Based on information from the Kamchatka Volcanic Eruption Response Team (KVERT 2006), an explosive eruption occurred at Bezymianny Volcano, Kamchatka, Russia at 09:17 UTC on 24 December 2006. This produced an ash cloud up to ~10 km ASL. We investigate the 24 December 2006 eruption using rapid-response data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), combined with field photographs of the deposit. Furthermore we consider thermal and textural observations on the deposits. Satellite images agreed with aerial photographs taken on 27 December 2006 showing the warm deposit (relative to the snow) concentrated in the south-eastern channel. We present data from rapid response images collected in conjunction to the Alaska Volcano Observatory (AVO) and suggest inferences toward future activity.

Carter, A. J.; Ramsey, M. S.; Girina, O.

2007-05-01

190

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

191

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

Microsoft Academic Search

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

Christian Huggel; Jacqueline Caplan-Auerbach; Christopher F. Waythomas; Rick L. Wessels

2007-01-01

192

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

193

Satellite and slow-scan-television observations of the rise and dispersion of ash-rich eruption clouds from Redoubt Volcano, Alaska  

SciTech Connect

Polar-orbiting NOAA 10 and 11 weather satellites with their Advanced Very High Resolution Radiometer (AVHRR) imaging sensors and the Landsat 4 and 5 satellites have provided over 30 images of the 1989/90 eruptions of Redoubt Volcano. Between December 14 and April 21, about 20 major explosive eruptions occurred with ash plumes rising to heights of 10 km or more, most of them penetrating the tropopause. The ash severely impacted domestic and international air traffic in Alaska with a near disaster on December 15, 1989, when a KLM 747-400 jet aircraft with 247 people aboard intercepted an ash plume and temporarily lost all four engines. Fortunately, the engines were eventually restarted after several attempts and the plane landed safely in Anchorage. The authors have used satellite and also slow-scan television (TV) observations to study the dynamics and thermodynamics of rising eruption plumes in order to better understand plume dispersal.

Kienle, J.; Woods, A.W.; Estes, S.A.; Ahlnaes, K.

1992-03-01

194

Interactive Volcano Studies and Education Using Virtual Globes  

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

195

Real-Time C-Band Radar Observations of 1992 Eruption Clouds from Crater Peak, Mount Spurr Volcano, Alaska  

Microsoft Academic Search

Repeated aircraft hazards in Alaska related to volcanic clouds have resulted in the use of a mobile C-band radar devoted to volcanic-cloud monitoring. The radar is located at Kenai, in range of several vol- canoes in the Cook Inlet area. Three significant erup- tions from the Crater Peak vent of Mount Spurr vol- cano (about 80 km from Kenai) in

William I. Rose; Alexander B. Kostinski; Lee Kelley

1992-01-01

196

Galactic Super Volcano Similar to Iceland Volcano  

NASA Video Gallery

This composite image from NASAs Chandra X-ray Observatory with radio data from the Very Large Array shows a cosmic volcano being driven by a black hole in the center of the M87 galaxy. This eruption is pumping energy into the black hole's surroundings and preventing hundreds of millions of new stars from forming just as the volcano in Iceland caused disruptions in the Earth's atmosphere.

Jim Wilson

2010-08-27

197

Volcano Live  

NSDL National Science Digital Library

Volcano Live contains maps of volcanoes from around the world, a kids' page that provides volcano education links for teachers and students, a volcano glossary, volcano news, links to live video cams of volcanoes, geography and volcano information of countries around the world, and video clips of active volcanoes. There is also information for travelling to volcanoes, a volcano photo section, a section on the destruction of Pompeii, a volcanology section, and volcano safety rules.

Seach, John

198

Relocation of Eruption-Related Earthquake Clusters at Augustine Volcano, Alaska, using Station-Pair Differential Times  

Microsoft Academic Search

Multiple families of repeating earthquakes at shallow depths occurring over multiple time scales have been identified prior to and during the 2005-2006 eruption of Augustine Volcano (DeShon et al., 2008). The use of conventional and double-difference location methods failed to result in stable locations for the events in these families, due primarily to noisy site conditions as well as unfavorable

L. Sumiejski; C. H. Thurber; H. R. Deshon

2008-01-01

199

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

Microsoft Academic Search

The 2005-2006 eruption of Augustine Volcano produced tephra-fall deposits during four eruptive phases. The island setting, deposition of thin, fine-grained fall deposits onto the snowpack, and subsequent reworking by high winds and surface-water flow has removed much of the original proximal fall record. During the late precursory phase (December 2005), small phreatic explosions produced very light, localized tephra fall. Tephra

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

2006-01-01

200

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

201

Volcano Lovers  

NSDL National Science Digital Library

This Why Files article explores volcanoes and volcanic eruptions. Topics covered include: Alaska's Pavlof and its threat to jet engines; Mexico City's restless neighbor, Popocatepetl (El Popo); underground volcanic processes; modern forecasting of eruptions; various volcanic phenomena and features; large flood basalt areas around the world; California's volcanically active area, Long Valley Caldera and Mammoth Mountain; Indonesia's Krakatau eruption in 1883, which was the world's largest historical eruption; Krakatau's ecological contribution to the study of colonization of sterile lands; and central Mexico's Paricutin which was witnessed emerging from a farmer's field in 1943. Three scientists were interviewed for this article.

Tenenbaum, David

1997-01-02

202

Volcanoes of North America  

NASA Astrophysics Data System (ADS)

Volcanoes of North America capitalises on the vast body of volcano literature now available to present, in a single source, detailed information about volcanoes found in North America. It contains brief accounts, written by leading experts in volcanology, of over 250 volcanoes and volcanic fields formed during the last 5 million years. The volcanoes of the continental United States, Alaska, Hawaii, and Canada are described. The precise location of each volcano is given, and the volcano is classified by type. Information about composition and eruptive history is also included. Each narrative description is accompanied by a photograph, a map of each location, and an extremely helpful statement on how to reach each volcano. The entries are mostly written at a level understandable by lay readers, but technical terms are also used and a background in geology is advantageous. Volcanoes of North America will be a standard reference work for practising volcanologists, petrologists, and geochemists, and to some extent, geographers. In addition, the maps and the 'How to get there' sections make this a highly valuable book for anyone interested in natural history or fascinated by volcanoes.

Wood, Charles Arthur; Kienle, Jürgen

1992-11-01

203

Types and Effects of Volcano Hazards  

NSDL National Science Digital Library

This United States Geological Survey (USGS) website discusses volcano hazards by type (gas, lahars, landslides, lava flows, pyroclastic flows, and tephra) and by the effect volcanoes have on people and land. This site gives an overview of volcano hazards and links to selected case studies listed by country, volcano, year, and type of hazard. Links to more USGS information about volcanoes, such as a photo glossary, a site index, observatories, and an educator's page are also provided.

204

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

NASA Astrophysics Data System (ADS)

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

Beget, J.

2006-12-01

205

Rear-arc vs. arc-front volcanoes in the Katmai reach of the Alaska Peninsula: A critical appraisal of across-arc compositional variation  

USGS Publications Warehouse

Physical and compositional data and K-Ar ages are reported for 14 rear-arc volcanoes that lic 11-22 km behind the narrowly linear volcanic front defined by the Mount Katmai-to-Devils Desk chain on the Alaska Peninsula. One is a 30-km3 stratocone (Mount Griggs; 51-63% SiO2) active intermittently from 292 ka to Holocene. The others are monogenetic cones, domes, lava flows, plugs, and maars, of which 12 were previously unnamed and unstudied; they include seven basalts (48-52% SiO2), four mafic andesites (53-55% SiO2), and three andesite-dacite units. Six erupted in the interval 500-88 ka, one historically in 1977, and five in the interval 3-2 Ma. No migration of the volcanic front is discernible since the late Miocene, so even the older units erupted well behind the front. Discussion explores the significance of the volcanic front and the processes that influence compositional overlaps and differences among mafic products of the rear-arc volcanoes and of the several arc-front edifices nearby. The latter have together erupted a magma volume of about 200 km3, at least four times that of all rear-arc products combined. Correlation of Sr-isotope ratios with indices of fractionation indicates crustal contributions in volcanic-front magmas (0.7033-0.7038), but lack of such trends among the rear-arc units (0.70298-0.70356) suggests weaker and less systematic crustal influence. Slab contributions and mantle partial-melt fractions both appear to decline behind the front, but neither trend is crisp and unambiguous. No intraplate mantle contribution is recognized nor is any systematic across-arc difference in intrinsic mantle-wedge source fertility discerned. Both rear-arc and arc-front basalts apparently issued from fluxing of typically fertile NMORB-source mantle beneath the Peninsular terrane, which docked here in the Mesozoic. ?? Springer-Verlag 2004.

Hildreth, W.; Fierstein, J.; Siems, D. F.; Budahn, J. R.; Ruiz, J.

2004-01-01

206

Rear-arc vs. arc-front volcanoes in the Katmai reach of the Alaska Peninsula: a critical appraisal of across-arc compositional variation  

NASA Astrophysics Data System (ADS)

Physical and compositional data and K-Ar ages are reported for 14 rear-arc volcanoes that lie 11-22 km behind the narrowly linear volcanic front defined by the Mount Katmai-to-Devils Desk chain on the Alaska Peninsula. One is a 30-km3 stratocone (Mount Griggs; 51-63% SiO2) active intermittently from 292 ka to Holocene. The others are monogenetic cones, domes, lava flows, plugs, and maars, of which 12 were previously unnamed and unstudied; they include seven basalts (48-52% SiO2), four mafic andesites (53-55% SiO2), and three andesite-dacite units. Six erupted in the interval 500-88 ka, one historically in 1977, and five in the interval 3-2 Ma. No migration of the volcanic front is discernible since the late Miocene, so even the older units erupted well behind the front. Discussion explores the significance of the volcanic front and the processes that influence compositional overlaps and differences among mafic products of the rear-arc volcanoes and of the several arc-front edifices nearby. The latter have together erupted a magma volume of about 200 km3, at least four times that of all rear-arc products combined. Correlation of Sr-isotope ratios with indices of fractionation indicates crustal contributions in volcanic-front magmas (0.7033-0.7038), but lack of such trends among the rear-arc units (0.70298-0.70356) suggests weaker and less systematic crustal influence. Slab contributions and mantle partial-melt fractions both appear to decline behind the front, but neither trend is crisp and unambiguous. No intraplate mantle contribution is recognized nor is any systematic across-arc difference in intrinsic mantle-wedge source fertility discerned. Both rear-arc and arc-front basalts apparently issued from fluxing of typically fertile NMORB-source mantle beneath the Peninsular terrane, which docked here in the Mesozoic.

Hildreth, Wes; Fierstein, Judy; Siems, David F.; Budahn, James R.; Ruíz, Joaquin

207

Earthquakes, Volcanoes, and Plate Tectonics  

NSDL National Science Digital Library

This page consists of two maps of the world, showing how earthquakes define the boundaries of tectonic plates. Volcanoes are also distributed at plate boundaries (the "Ring of Fire" in the Pacific) and at oceanic ridges. It is part of the U.S. Geological Survey's Cascades Volcano Observatory website, which features written material, images, maps, and links to related topics.

208

Mount St. Helens VolcanoCam  

NSDL National Science Digital Library

This webcam shows a static image of Mount St. Helens taken from the Johnston Ridge Observatory. The Observatory and VolcanoCam are located at an elevation of approximately 4,500 feet, about five miles from the volcano. The observer is looking approximately south-southeast across the North Fork Toutle River Valley. The VolcanoCam image automatically updates approximately every five minutes. Other features include current conditions reports, weather updates, an image achive, and eruption movies. In addition, there are frequently asked questions, and information about using the VolcanoCam image and funding for the VolcanoCam.

209

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

210

Deep magmatic degassing versus scrubbing: Elevated CO2 emissions and C/S in the lead-up to the 2009 eruption of Redoubt Volcano, Alaska  

NASA Astrophysics Data System (ADS)

We report CO2, SO2, and H2S emission rates and C/S ratios during the five months leading up to the 2009 eruption of Redoubt Volcano, Alaska. CO2emission rates up to 9018 t/d and C/S ratios ?30 measured in the months prior to the eruption were critical for fully informed forecasting efforts. Observations of ice-melt rates, meltwater discharge, and water chemistry suggest that surface waters represented drainage from surficial, perched reservoirs of condensed magmatic steam and glacial meltwater. These fluids scrubbed only a few hundred tonnes/day of SO2, not the >2100 t/d SO2expected from degassing of magma in the mid- to upper crust (3-6.5 km), where petrologic analysis shows the final magmatic equilibration occurred. All data are consistent with upflow of a CO2-rich magmatic gas for at least 5 months prior to eruption, and minimal scrubbing of SO2by near-surface groundwater. The high C/S ratios observed could reflect bulk degassing of mid-crustal magma followed by nearly complete loss of SO2in a deep magmatic-hydrothermal system. Alternatively, high C/S ratios could be attributed to decompressional degassing of low silica andesitic magma that intruded into the mid-crust in the 5 months prior to eruption, thereby mobilizing the pre-existing high silica andesite magma or mush in this region. The latter scenario is supported by several lines of evidence, including deep long-period earthquakes (-28 to -32 km) prior to and during the eruption, and far-field deformation following the onset of eruptive activity.

Werner, Cynthia; Evans, William C.; Kelly, Peter J.; McGimsey, Robert; Pfeffer, Melissa; Doukas, Michael; Neal, Christina

2012-03-01

211

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

212

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

USGS Publications Warehouse

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

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

2010-01-01

213

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

214

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

215

Depths of Magma Reservoirs Inferred from Preeruptive Dissolved Volatiles in the Most Recent Postcaldera Eruptions of Aniakchak Volcano, Alaska  

NASA Astrophysics Data System (ADS)

Aniakchak volcano, 670 km southwest of Anchorage in the Aleutian arc, erupted rhyodacite and andesite in its caldera-forming eruption ~3500 B.P. Numerous small-volume postcaldera eruptions produced basaltic andesite to dacite. Chemical analyses of melt inclusions (MI) trapped in phenocrysts in pumice and scoria yield estimates of dissolved magmatic volatile concentrations before Aniakchak's three most recent eruptions. Preeruptive H2O and CO2 concentrations constrain magma storage depths. Valid depth estimates require that MI are representative of magma storage environment, MI did not leak or crystallize, and crystals grew in vapor-saturated host magma. MI were analyzed in plagioclase from the compositionally similar dacitic eruptions of Half Cone ( ~400 B.P.; n=13) and 1931 (n=20), and in olivine (Fo71-74) from the intervening basaltic andesitic eruption of Blocky Cone (n=22). Although microscopic textures show that phenocrysts had complex growth histories, compositional data suggest that many intact MI preserve magma storage depth information. Concentrations of major elements, S, Cl, and F in MI were determined by electron microprobe. H2O and CO2 were measured by infrared spectroscopy (FTIR). CO2 below the ~20 ppm FTIR detection limit in all MI, and co-variation of S and H2O, indicate crystallization during passive, open-system degassing at a range of depths in the upper crust. Halogen concentrations increase with differentiation in both dacitic and basaltic andesitic MI. Concentrations of Cl ( ~1800 ppm) and F (400-500 ppm) in dacitic MI are typical of evolved arc magmas and could have been generated by fractional crystallization of basaltic andesite of Blocky Cone. Because these elements are not strongly partitioned into hydrous vapor relative to silicate melt and are incompatible in observed crystals, they become enriched in residual melts as crystallization proceeds. Weighted mean H2O values for dacites (2.9, 4.1 wt.%) yield trapping pressures of 60 MPa (2.8 km) for the 400 B.P. and 110 MPa (5.1 km) for the 1931 magmas. MI from basaltic andesite of Blocky Cone show a large range in H2O concentrations (up to 2.7 wt.%) and only the highest are likely to represent magmatic conditions at depth. These MI indicate depths similar to the 400 B.P. dacite, suggesting that basaltic andesitic magma ascended to ~3 km, where significant phenocryst growth took place, perhaps in response to ejection of a relatively large amount of dacitic magma in the preceding Half Cone and nearby Vent Mountain eruptions. Aniakchak rock and mineral chemistries show that many postcaldera eruptions ejected dacite plus recharge andesite or basaltic andesite. The MI data indicate that mixing to form coeval hybrid andesites occurred at depths <5 km.

Bacon, C. R.

2002-05-01

216

Variations in deformation rates and magma composition at Augustine Volcano, Alaska: A mechanical account of the 2006 eruption  

NASA Astrophysics Data System (ADS)

Deformation rates preceding and concurrent with the 2006 eruption of Augustine Volcano show marked spatial and temporal variability. Seven distinct periods of deformation can be identified in the time series: (1) early precursory inflation, beginning in mid-summer 2005; (2) late precursory inflation, beginning late November 2005; (3) first syn-eruption inflation, beginning January 11, 2006; (4) first syn-eruptive deflation, beginning January 28; (5) second syn-eruptive inflation, beginning February 10; (6) second syn-eruptive deflation, beginning March 1; and (7) the return to background, beginning in late spring 2006. The different periods of deformation arise from three different volcanic sources: (1) a shallow center of pressurization located beneath the summit at a depth near sea level; (2) an ascending dike, which propagated upward from sea-level to the summit between late November 2005 and January 11, 2006; and (3) a deep source of withdrawal, centered below the summit at ~10 km depth. Magma compositions also show temporal variability. Initial juvenile material, erupted explosively and effusively in mid-January, comprises mostly low-SiO2 andesite. A crystal-rich, high-SiO2 andesite dome grew during the last part of January, and explosions on January 27 and 28 followed by continuous eruption through February 2 caused partial destruction of the new dome and emplacement of extensive pyroclastic flows. These were composed primarily of high-SiO2 andesite, with subordinate low-SiO2 andesite. Slow lava effusion continued throughout February and early March, but, in mid-March, extrusion rates increased dramatically, leading to growth of a larger summit lava dome and two lava flows composed primarily of low- SiO2 andesite. Throughout the sequence, but especially during late January, mixing of high and low- SiO2 andesites was evidenced by banded clasts, clasts of intermediate compositions, and varying proportions of clast types. Taken together, the geodetic time series and the mafic-silicic-mafic temporal variation in dominant magma compositions tell a story of how the unrest and subsequent eruption may have evolved. During the early precursory period, low-SiO2 andesite slowly ascended from depth and accumulated beneath the edifice near sea level. The late precursory period saw the upward propagation of a low-SiO2 andesitic dike, which culiminated in the explosions of January 11. In mid January, the low-SiO2 andesite alternately extruded as a dome and erupted explosively. During this period, the sea-level magma chamber continued to pressurize, apparently because magma accumulation was greater than extrusion. Residual, crystal-rich, high-SiO2 andesite, left over from the 1976 and 1986 eruptions, also resided at this depth but did not erupt in great quantities during mid-January, likely due to its high crystallinity. By late January, however, this high-SiO2 andesite was apparently mobile enough to effuse as a dome that collapsed into voluminous pyroclastic flows. This uncapped the magmatic system, allowing rapid ascent of new low-SiO2 andesite from depth (~10 km), which led to the first syn-eruptive (deep) deflation. In early February, the weight of newly effused lava began to inhibit extrusion while magma continued to accumulate at sea level, leading to the second syn-eruptive inflation. By early March, low- SiO2 andesite that began ascent from ~10 km had accumulated in great enough quantity to cause renewed effusion, resulting in the new, low-SiO2 dome and lava flows, and the second syn-eruptive deflation.

Cervelli, P. F.; Coombs, M. L.

2006-12-01

217

The 1986 Eruption of Augustine Volcano, Alaska A Case Study on the Effect of Magma Composition on Degassing-induced Crystallization During Magma Ascent  

NASA Astrophysics Data System (ADS)

The six-month-long 1986 eruption of Augustine Volcano in south-central Alaska began explosively (producing pumiceous pyroclastic flows; ppf) and culminated in two discrete periods of lava dome growth and collapse (producing lithic pyroclastic flows; lpf). Throughout the eruption, juvenile clast compositions spanned the entire andesite range (about 57 to 63 wt.% SiO2) while clast densities, regardless of composition, increased noticeably between the pumiceous and lithic pyroclastic-flow phases. Maximum water contents preserved in melt inclusions are 5 to 7 wt.%, suggesting magma storage depths of 5-6 km. The broad range in juvenile clast compositions erupted simultaneously from similar depths and with similar initial water contents make the 1986 Augustine eruptive products an ideal sample suite in which to study the effects of bulk chemistry on the kinetics of groundmass crystallization during ascent. Clasts from the ppf deposits show a clear correlation of composition with both density and groundmass crystallinity. Specifically, mafic andesites (<59 wt.% SiO2) have densities of 1.2 to 2 g/cc, numerous euhedral plagioclase microlites and irregularly shaped bubbles, whereas the most silicic andesites (>62 wt.% SiO2) have densities of 0.5 to 1.3 g/cc, few microlites and large spherical bubbles. These differences indicate more extensive syn-ascent (degassing-induced) crystallization and gas loss from the mafic magma than from the silicic magma under similar, relatively rapid magma ascent rates of the explosive phase. Comparison of low- and high-density clasts of intermediate (59-61 wt.% SiO2) composition shows that low-density (<1.5 g/cc) ppf clasts have numerous small euhedral to acicular plagioclase microlites and numerous vesicles, whereas high-density (>2.0 g/cc) lpf clasts have numerous large (and commonly zoned) microlites, few vesicles, and often late-stage quartz precipitation. The more extensive crystallization and degassing of clasts in the dome-derived lpf deposits are consistent with relatively slower ascent rates associated with lava dome formation. Interestingly, in the most silicic andesite clasts (>62 wt.% SiO2) increases in clast density (0.5 to 1.9 g/cc) correspond largely to bubble collapse alone, with only minor increases in microlite nucleation and growth. Observations from the heterogeneous 1986 Augustine deposits demonstrate that, at similar water contents and original starting depths, degassing-induced crystallization occurs much more readily in mafic magmas than in silicic ones. Moreover, groundmass glass compositions (75 to 78 wt.% SiO2) in all samples approach the feldspar-quartz cotectic, suggesting that the extent of syn-ascent crystallization is limited by the kinetics of quartz crystallization. To the degree that changes in rheology caused by degassing-induced crystallization modulate the rate, style, and duration of eruptive activity, these basic observations may help explain differences in dominant eruption styles between mafic and silicic volcanoes and raise interesting questions about the nature of eruptive transitions in homogeneous vs. heterogeneous magmas.

Gardner, C. A.; Cashman, K. V.; Roman, D. C.

2006-12-01

218

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.

219

Alaska Science Forum  

NSDL National Science Digital Library

The Alaska Science Forum Web site is provided by the Geophysical Institute of the University of Alaska Fairbanks. The forum consists of articles written about various science subjects by scientists from the Geophysical Institute. Categories include the aurora, earthquakes, fun science facts, historic Alaska, mountains, rocks and geology, volcanoes, weather, and more. One of the latest articles, by Ned Rozell, is titled: Bogs, Permafrost and the Global Carbon Equation. Each of the articles is listed along with the author's name and a direct link to the online publication, most of which are fairly short and geared towards nonscientists making reading easy and interesting. [JAB

220

Exploring Means of Determining Surface Deformation at Augustine Volcano  

NASA Astrophysics Data System (ADS)

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 we primarily use remotely sensed data, with SAR derived products and techniques as a focus, we also explore the use of ICESAT data. Deformation started in the summer of 2005, with a period of inflation leading up to the January 2006 eruption and which was then followed by a period deflation. The deformation of the flanks of Augustine island was subtle, and GPS stations at the perimeter of the island generally show less that 2cm of total deformation. The summit GPS stations show significantly greater inflation, however these stations were destroyed during the eruption. Traditional INSAR has difficulties when applied to a volcano like Augustine, due to the small area of the island, its large topographic relief, the deposition of ash over the large areas of the island and the long orbital repeat interval of current SAR satellites, all work against the technique. This does not mean however that the outlook is bleak, Permanent Scatterer (PS) INSAR related techniques show great potential. The scientific basis of each technique examined is explained along with the challenges, and limitations that are inherent therein. Deformation results obtained from each method are also presented, and compared with the GPS measurements. The following techniques are examined, 1) INSAR/DINSAR, 2) Permanent Scatterers, 3) Delta K interferometry, 4) ICESAT LIDAR integration, 5) SAR layover/shadow mapping and geometric techniques. Because eruptions at small island volcanoes are common throughout the Aleutian chain, techniques developed for the analysis of this eruption will have great applicability to these and other arc volcanoes.

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

2006-12-01

221

USGS Photo glossary of volcano terms  

NSDL National Science Digital Library

This website, part of the USGS Volcano Hazards Program, can help users distinguish among various types of volcanoes, vents, eruption types, and ejected material. The site features an extensive list of volcanic vocabulary, along with photographs and text for each entry. Users can also check out the latest U.S. volcanic activity reported by the USGS volcano observatories, which are linked to the page.

Usgs

222

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

223

Standardisation of the USGS Volcano Alert Level System (VALS): analysis and ramifications  

NASA Astrophysics Data System (ADS)

The standardisation of volcano early warning systems (VEWS) and volcano alert level systems (VALS) is becoming increasingly common at both the national and international level, most notably following UN endorsement of the development of globally comprehensive early warning systems. Yet, the impact on its effectiveness, of standardising an early warning system (EWS), in particular for volcanic hazards, remains largely unknown and little studied. This paper examines this and related issues through evaluation of the emergence and implementation, in 2006, of a standardised United States Geological Survey (USGS) VALS. Under this upper-management directive, all locally developed alert level systems or practices at individual volcano observatories were replaced with a common standard. Research conducted at five USGS-managed volcano observatories in Alaska, Cascades, Hawaii, Long Valley and Yellowstone explores the benefits and limitations this standardisation has brought to each observatory. The study concludes (1) that the process of standardisation was predominantly triggered and shaped by social, political, and economic factors, rather than in response to scientific needs specific to each volcanic region; and (2) that standardisation is difficult to implement for three main reasons: first, the diversity and uncertain nature of volcanic hazards at different temporal and spatial scales require specific VEWS to be developed to address this and to accommodate associated stakeholder needs. Second, the plural social contexts within which each VALS is embedded present challenges in relation to its applicability and responsiveness to local knowledge and context. Third, the contingencies of local institutional dynamics may hamper the ability of a standardised VALS to effectively communicate a warning. Notwithstanding these caveats, the concept of VALS standardisation clearly has continuing support. As a consequence, rather than advocating further commonality of a standardised VALS, we recommend adoption of a less prescriptive VALS that is scalable and sufficiently flexible for use by local stakeholders via standardised communication products designed to accommodate local contingency, while also adhering to national policy.

Fearnley, C. J.; McGuire, W. J.; Davies, G.; Twigg, J.

2012-11-01

224

Administrative History of Hawaii Volcanoes National Park and Haleakala National Park.  

National Technical Information Service (NTIS)

Contents: Introduction: Early European Visitors; The Volcano House; Hawaiian Volcano Observatory; Kilauea Military Camp; A National Park; General Improvements; Interpretation and Education; Flora and Fauna; Mauna Loa; and Administration.

F. Jackson

1972-01-01

225

Collapsing volcanoes  

Microsoft Academic Search

A series of studies has been conducted which examined Landsat images of volcanoes in the central Andes in order to identify previously unknown avalanche deposits, with attention to the Socompa volcano in Chile. The occasional, massive collapse of an unstable volcanic cone may be seen as a normal event in the life cycle of a volcano; this is especially true

Peter Francis; Stephen Self

1987-01-01

226

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  

Microsoft Academic Search

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

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

2008-01-01

227

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.

228

Observations of a nuée ardente from the St. Augustine volcano  

Microsoft Academic Search

A series of aerial photographs were obtained for a nuée ardente produced by the February 8, 1976 eruption of the St. Augustine volcano, Alaska. The nuée ardente reached a maximum velocity of 50 m s-1 while descending the steeper (~1:3) slope of the volcano. It later slowed to a velocity of 6 m s-1 as it traversed the gentler slope

Jeffrey L. Stith; Peter V. Hobbs; Lawrence F. Radke

1977-01-01

229

Volcano Types  

NSDL National Science Digital Library

This site lists the basic types of volcanoes: scoria cone, shield volcano, and stratovolcano. Each is described in terms of shape, composition, and eruption type, and links are available to additional information. Subordinate types listed include fissure eruptions, spatter cones, hornitos, and hydrovolcanic eruptions. The site also explains when a volcano is considered active, dormant, or extinct. In addition, generic features such as vent, central vent, edifice, magma chamber, parasitic cones, and fumaroles are listed and described.

Camp, Victor

230

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

231

Decade Volcanoes  

NSDL National Science Digital Library

In the 1990s, the International Association of Volcanology and Chemistry of the Earth's Interior started the Decade Volcano Project. As part of their work, they designated sixteen volcanoes particularly worthy of study "because of their explosive histories and close proximity to human populations." The group recently teamed up with National Geographic to create a guide to these volcanoes via this interactive map. Navigating through the map, visitors can learn about Mount Rainier, Colima, Galeras, Santorini, and other prominent volcanoes. For each volcano, there's a brief sketch that gives the date of its last eruption, its elevation, nearby population centers, and a photograph. Additionally, visitors can learn more by clicking on the sections titled "Did You Know?" and "Eruption Interactive".

2007-11-02

232

Lowell Observatory  

NASA Astrophysics Data System (ADS)

Lowell Observatory, founded in 1894 by Percival Lowell, is one of the largest independent, privately managed observatories in the world. Endowed by its founder, Lowell Observatory continues today as a private research institution dedicated to the study of astronomy. The large redshifts of galaxies were discovered by Lowell astronomer Vesto M Slipher. In 1930, Clyde Tombaugh discovered Pluto ...

Murdin, P.

2000-11-01

233

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

234

Seismo-acoustics, VLP and ULP signals, and other comparisons of surface broadband and CALIPSO borehole data at Soufriere Hills Volcano, Montserrat, B.W.I  

Microsoft Academic Search

Project CALIPSO (Caribbean Andesite Lava Island-volcano Precision Seismo-geodetic Observatory) investigates with borehole and surface instruments the magmatic system at the very active Soufriere Hills Volcano (SHV), Montserrat, supplementing surface monitoring systems of the Montserrat Volcano Observatory, and those of other institutions including PSU and U Ark. Many aspects of andesitic magmatic system dynamics remain little understood despite significant monitoring and

D. Hidayat; B. Voight; G. Mattioli; S. R. Young; A. T. Linde; I. S. Sacks; P. E. Malin; E. Shalev; D. Elsworth; C. Widiwijayanti; R. Herd; G. Thompson; V. Bass

2003-01-01

235

Collapsing volcanoes  

NASA Astrophysics Data System (ADS)

A series of studies has been conducted which examined Landsat images of volcanoes in the central Andes in order to identify previously unknown avalanche deposits, with attention to the Socompa volcano in Chile. The occasional, massive collapse of an unstable volcanic cone may be seen as a normal event in the life cycle of a volcano; this is especially true in the case of large 'stratovolcanoes', of which there are many hundreds in the 'Ring of Fire' around the Pacific rim. Stratovolcanoes are susceptible to collapse because of their association with subduction zones. Three kinds of collapse can be distinguished among stratovolcanoes.

Francis, Peter; Self, Stephen

1987-06-01

236

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.

237

University of Tokyo: Volcano Research Center (VRC)  

NSDL National Science Digital Library

This website discusses the Volcano Research Center's (VRC) work to improve predictions of volcanic eruptions by conducting research on volcanic processes. Users can find out about Asama, Kirishima, Izu-Oshima, and other VRC volcano observatories. The website features information on many continuing and recent eruptions in Japan. Visitors can view many images of volcanic eruptions and disaster relief missions. Researchers can learn about the international cooperative drilling operation at the Unzen Volcano to understand the eruption mechanisms and magnetic activity. This site is also reviewed in the February 20, 2004 _NSDL Physical Sciences Report_.

238

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

239

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

240

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

241

Application of wave-theoretical seismoacoustic models to the interpretation of explosion and eruption tremor signals radiated by Pavlof volcano, Alaska  

NASA Astrophysics Data System (ADS)

Tremor and explosion signals recorded on September 29 during the Fall 1996 Pavlof eruption are interpreted using video images, field observations, and seismic data. Waveform analysis of tremor and explosions provided estimates of the melt's volcano-acoustic parameters and the magma conduit dimensions. Initial mass fractions of 0.25% water and 0.025% carbon dioxide in the melt can explain the resonance characteristics of the tremor and explosion pulses inferred from seismic data. The magma conduit is modeled as a three-section rectangular crack. We infer that the tremor-radiating region consists of the lowermost two sections, both with cross-sectional areas of ˜10 m2. The deeper section is 43 m long, with magma sound speed of 230 m/s, density of 2600 kg/m3, and viscosity of 1.0×106 Pa s. The section above it, defined by the water nucleation depth, is 64 m long, with magma sound speed of 91 m/s, density of 2000 kg/m3, and viscosity of 1.4×l06 Pa s. An average magma flow velocity of 1.2 m/s, with superposed random oscillations, acts as the tremor source. Explosions are postulated to occur in the uppermost part of the magma conduit after water comes out of solution. The explosion source region consists of a 15 m long section, with cross-sectional area of 20 m2, sound speed of 51 m/s, density of 1000 kg/m3, and viscosity of 1.5×103 Pa s. A burst pressure of 220 MPa at 14 m depth would generate an acoustic pulse whose amplitude and character match the observed signal. Waveform analysis of the explosion pulses shows that the explosive event may be preceded by a long-period fluid transient which may trigger the metastable magma-gas mixture. The modeling procedure illustrates the synergy of fluid dynamic, seismic, and acoustic models and data with geological and visual observations.

Garces, Milton A.; McNutt, Stephen R.; Hansen, Roger A.; Eichelberger, John C.

2000-02-01

242

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

243

Introduction to Augustine Volcano and Overview of the 2006 Eruption  

NASA Astrophysics Data System (ADS)

This overview represents the combined efforts of scores of people, including Alaska Volcano Observatory staff from the US Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys; additional members of those agencies outside of AVO; and volcanologists from elsewhere. Augustine is a young, and therefore small island volcano in the Cook Inlet region of the eastern Aleutian arc. It is among the most active volcanoes in the arc, with six major historic eruptions, and a vigorous eruptive history going back at least 2,500 years. Eruptions typically begin explosively, and finish with the extrusion of domes and sometimes short, steep lava flows. At least 14 times (most recently in 1883) the -summit has become over-steepened and failed, producing debris avalanches which reached tidewater. Magmas within each of the well-studied eruptions are crystal-rich andesite spanning up to seven weight percent silica. Mixing and mingling are ubiquitous and occur at scales from meters to microns. In general, magmagenesis at Augustine is open, messy, and transcrustal. The 2006 eruption was broadly similar to the 20th century eruptions. Unrest began midway through 2005, with steadily increasing numbers of microearthquakes and continuous inflation of the edifice. By mid-December there were obvious morphological and thermal changes at the summit, as well as phreatic explosions and more passive venting of S-rich gasses. In mid-January 2006 phreatomagmatic explosions gave way to magmatic explosions, producing pyroclastic flows dominated by low-silica andesite, as well as lahars, followed by a small summit dome. In late January the nature of seismicity, eruptive style, and type of erupted magma all changed, and block-and-ash flows of high-silica, crystal-rich andesite were emplaced as the edifice deflated. Re-inflation well below the edifice and low-level effusion continued through February. During the second week in March there was a marked increase in extrusion, resulting in two short, steep lava flows dominantly composed of low-silica andesite. Effusion slowly waned through March and deformation ceased. Previous eruptions have had months-long repose followed be renewed effusion, but this has not yet happened during this eruption. Our ability to describe this eruption is based on a richness of data. The volcano was well instrumented with AVO seismometers and Earthscope/PBO continuous GPS instruments. Additional instruments were added as unrest increased, and substitutes for stations destroyed during initial explosions were deployed. As many as two-dozen AVHRR satellite passes were analyzed each day, providing thermal monitoring and ash-plume tracking. Overflights collected both visual and quantitative IR imagery on a regular basis. Georeferenced imagery acquired by satellite (ASTER) and repeated conventional aerial photography permitted detailed, accurate, mapping of many deposits as an aid to (but not substitute for) field mapping. Web cameras (both visual and near-IR) and conventional time-lapse cameras aided understanding of ongoing processes. Data sets less common to volcano monitoring (infrasound, lightning detection) extended our understanding.

Nye, C. J.

2006-12-01

244

Iridium emissions from Kilauea Volcano  

NASA Astrophysics Data System (ADS)

During May 1983, gas and particulate samples were collected at the cooling vents of Kilauea volcano in Hawaii. Three vents on the southeast rift zone were sampled using base-treated filter packs to absorb acidic gases and Teflon filters for particles. The samples were analyzed for 40 elements by nondestructive neutron activation analysis. As with other volcanoes, the chalcophilic and volatile elements were enriched by up to seven orders of magnitude relative to the erupted basalt. Unlike the case of other volcanoes, iridium was observed to be highly enriched (105 fold) at the two higher temperature vents, and the degree of enrichment appears to be related to both high temperatures and high fluorine content of the gases. Estimates of the emission rates of Ir during eruptions of Kilauea based on the measurements reported here and those of the Hawaiian Volcano Observatory yield an emission rate of about 3 g Ir per 106 m3 of magma. This rate amounts to only about 0.3% of the Ir present in the magma that is being released by the volcano. This previously unidentified Ir source to the atmosphere and ocean may have a significant influence on the geochemical cycle of Ir on the earth. The uniqueness of Kilauea in its emissions of Ir is probably related to the deep source of magma, which contains significant levels of Ir (0.32 ppb) and high levels of the halogens F and Cl.

Olmez, I.; Finnegan, D. L.; Zoller, W. H.

1986-01-01

245

Digital data set of volcano hazards for active Cascade Volcanos, Washington  

USGS Publications Warehouse

Scientists at the Cascade Volcano Observatory have completed hazard assessments for the five active volcanos in Washington. The five studies included Mount Adams (Scott and others, 1995), Mount Baker (Gardner and others, 1995), Glacier Peak (Waitt and others, 1995), Mount Rainier (Hoblitt and others, 1995) and Mount St. Helens (Wolfe and Pierson, 1995). Twenty Geographic Information System (GIS) data sets have been created that represent the hazard information from the assessments. The twenty data sets have individual Open File part numbers and titles

Schilling, Steve P.

1996-01-01

246

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

247

Spreading volcanoes  

USGS Publications Warehouse

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, A.; Delaney, P. T.; Denlinger, R. P.

2000-01-01

248

Investigating Magma Withdrawal Dynamics During Plinian Eruptions Through Mineral and Eruptive Stratigraphies: Examples From the Chemically Zoned 400 yr BP Eruption of Half Cone Volcano, Aniakchak National Park, Alaska  

NASA Astrophysics Data System (ADS)

Half Cone volcano is the eviscerated remnant of a post-caldera composite volcano on the northwest floor of Aniakchak caldera (Alaska). The pyroclastic deposit produced during the 400 yr BP cataclysmic eruption of Half Cone is divisible in two volumetrically subequal fall units as well as a late-stage, lithic-rich, near-vent series of pyroclastic density current deposits and lava flow. The base of the deposit, known as the Pink Pumice, is composed of highly vesicular, crystal poor, and oxidized dacite pumice clasts (63-67% SiO2). Two stratigraphic horizons exist within this unit represented in outcrop by distinctly coarser-grained pumice and lithic clasts compared to the Pink Pumice's uppermost, middle, and lowermost levels. Overlying the Pink Pumice is the Brown Pumice layer, a brown-colored crystal-rich andesitic pumice fall (58-62% SiO2) with an abruptly coarse-grained base that normally grades upward. Although the contact between the Pink and Brown Pumice layers is abrupt in outcrop due to changes in color, vesicularity, and crystal content, whole-rock compositions plot along a linear continuum that ranges from andesite to rhyodacite. Isopach and isopleth mapping of the Pink Pumice indicate eruption column heights of 22-26 km for the coarser horizons, compared to only 12-15 km for uppermost, middle, and lowermost levels. Similar mapping of the upper and lower Brown Pumice indicate a declining plume from 20-24 km at the base to less than 15 km at the top. Granulometric analysis of lithic clasts coupled with electron microbeam analyses of individual phenocrysts and glass from the Pink and Brown Pumice indicate diverse lithic and mineral populations at horizons indicative of greater mass flux (plume height) compared to other levels in the deposit. Coarser-grained horizons contain granitic (quartz, feldspar, and mica) lithic fragments, oscillatory zoned plagioclase with An58-78 cores and An57-64 rims, and Fe-Ti oxide pairs yielding temperatures of 850- 890C. In contrast, levels indicative of lower eruption energy contain few granitic lithics, nearly unzoned plagioclase ranging from An58 to An62, and Fe-Ti oxide pairs that yield temperatures of 850-865C. Interestingly, glass compositions linger from 69-74% SiO2 throughout the Pink and Brown Pumice regardless of stratigraphic horizon. These observations suggest that (1) the magma chamber feeding the 400 yr BP eruption of Half Cone resulted via differentiation crystallization of an andesite liquid as evidenced by uniform glass compositions through the Pink and Brown Pumice stratigraphy coupled by increased crystal content in the Brown Pumice; (2) the magma chamber was intermittently tapped at deeper or shallower depths due to fluctuating mass flux, resulting in the eruption of heterogeneous mineral and lithic populations during periods characterized by higher mass flux compared to more uniform mineral and lithic populations during periods of lower mass flux; and (3) the combination of microbeam analyses of individual phenocrysts with granulometric and stratigraphic analyses is an effective tool in the investigation of magma withdrawal dynamics during Plinian eruptions.

Browne, B.

2006-12-01

249

Predicting and Validating the Tracking of a Volcanic Ash Cloud during the 2006 Eruption of Mt. Augustine Volcano  

Microsoft Academic Search

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

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

2008-01-01

250

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

251

Punctuated Evolution of Volcanology: An Observatory Perspective  

Microsoft Academic Search

Volcanology from the perspective of crisis prediction and response-the primary function of volcano observatories-is influenced both by steady technological advances and singular events that lead to rapid changes in methodology and procedure. The former can be extrapolated somewhat, while the latter are surprises or shocks. Predictable advances include the conversion from analog to digital systems and the exponential growth of

W. C. Burton; J. C. Eichelberger

2010-01-01

252

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.

253

CALIPSO Borehole Monitoring Project at Soufriere Hills Volcano, Montserrat, BWI: Overview, and Response of Magma Reservoir to Prodigious Dome Collapse  

Microsoft Academic Search

Project CALIPSO (Caribbean Andesite Lava Island Precision Seismo-geodetic Observatory) aims to investigate the magmatic system at the active Soufriere Hills Volcano (SHV), Montserrat. The collaborative project involves several institutions acting in partnership with the Montserrat Volcano Observatory (MVO), and is funded by NSF with assistance by NERC. SHV remains active after 9 years, displaying cyclic activity on several scales. Many

B. Voight; G. S. Mattioli; A. T. Linde; I. S. Sacks; S. R. Young; P. E. Malin; E. Shalev; D. Hidayat; D. Elsworth; C. Widiwijayanti; V. Miller; N. McWhorter; B. Schleigh; W. Johnston; R. Sparks; J. Neuberg; V. Bass; P. Dunkley; R. Herd; A. Jolly; G. Norton; T. Syers; G. Thompson; C. Williams; D. Williams; A. B. Clarke

2004-01-01

254

Dyer Observatory  

NASA Astrophysics Data System (ADS)

The Arthur J Dyer Observatory is the principal astronomical facility of Vanderbilt University. It is located about 16 km south of Nashville near Brentwood, Tennessee at an elevation of 345 m above sea level....

Murdin, P.

2000-11-01

255

Publications of the Volcano Hazards Program 2011  

USGS Publications Warehouse

The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic Hazards Assessments subactivity, as funded by Congressional appropriation. Investigations are carried out by the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute, University of Hawaii Manoa and Hilo, University of Utah, and University of Washington Geophysics Program. This report lists publications from all these institutions. Only published papers and maps are included here; abstracts presented at scientific meetings are omitted. Publication dates are based on year of issue, with no attempt to assign them to fiscal year.

Nathenson, Manuel

2013-01-01

256

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

257

Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 through December 31, 2006.  

National Technical Information Service (NTIS)

Between January 1 and December 31, 2006, AVO located 8,666 earthquakes of which 7,783 occurred on or near the 33 volcanoes monitored within Alaska. Monitoring highlights in 2006 include: an eruption of Augustine Volcano, a volcanic-tectonic earthquake swa...

C. Searcy J. A. Power J. P. Dixon S. D. Stihler

2007-01-01

258

Evaluation of satellite derived sulfur dioxide measurements for volcano monitoring during the 2009 Redoubt eruption (Invited)  

NASA Astrophysics Data System (ADS)

Changes in sulfur dioxide (SO2) emissions frequently precede volcanic eruptions, thus regular monitoring of volcanic SO2 emissions may facilitate more accurate eruption forecasting. Recent advancements in detection capabilities by both ultraviolet and infrared satellite sensors have made satellite remote sensing a viable tool for monitoring SO2 emissions during volcanic unrest; however, the extent to which satellite-generated SO2 data concur with traditional airborne SO2 measurements requires investigation. During the recent eruption of Redoubt Volcano, Alaska, which commenced in March 2009, SO2 emissions were detected on a near-daily basis by the Ozone Monitoring Instrument (OMI) on the Aura satellite. During explosive events, SO2 was also detected by the Atmospheric Infrared Sounder (AIRS) on the Aqua satellite. Preliminary satellite-derived SO2 burdens from the first three months of the eruption range from 80,000 tonnes during explosive activity to 3000 tonnes during passive degassing. These satellite measurements, several of which coincided with airborne SO2 measurements conducted by the Alaska Volcano Observatory (AVO), provide a rare opportunity to evaluate the efficacy of satellite SO2 measurements for volcano monitoring in Alaska, where remote sensing of volcanic unrest is an invaluable tool. Satellite-derived SO2 burdens have supplemented approximately weekly airborne measurements of SO2 emissions from Redoubt since March 2009; however, direct integration of the two datasets has been hindered because satellite and airborne measurements are reported as instantaneous SO2 mass and daily SO2 emission rate, respectively. Integration of satellite and airborne measurements would provide a more complete record of SO2 emissions because satellites detect SO2 during explosive, ash-rich eruptions when airborne measurements are not possible, and measure SO2 on a daily basis, a greater temporal resolution than is feasible by airborne methods alone. This will result in improved constraints on the volatile budget throughout an eruption, which may permit more effective eruption forecasting. Herein, we report OMI and AIRS SO2 measurements during the 2009 Redoubt eruption, which featured explosive eruptions to stratospheric altitudes and tropospheric gas plumes to altitudes of approximately three kilometers. We test a simple algorithm to convert the OMI SO2 burdens to SO2 emission rates for direct comparison with airborne measurements, and compare temporally and spatially coincident satellite and airborne SO2 measurements to evaluate the accuracy of OMI SO2 column amounts and derived burdens.

Lopez, T. M.; Carn, S. A.; Webley, P.; Pfeffer, M. A.; Doukas, M. P.; Kelly, P. J.; Werner, C. A.; Prata, F.; Schneider, D. J.; Cahill, C. F.

2009-12-01

259

Volcano Explorer: Build A Virtual Volcano  

NSDL National Science Digital Library

This website allows you to build virtual volcanoes and model their eruptions by changing gas and viscosity levels. Interactive screens define vocabulary and explain volcanic activity of three common volcano categories.

260

Intense Rainfall During Hurricane Mitch Triggers Deadly Landslide and Lahar at Casita Volcano, Nicaragua, on October 30, 1998  

NSDL National Science Digital Library

This web site illustrates and describes damage from a tragic lahar triggered by rainfall on Casita Volcano, an inactive cone of San Cristobal Volcano, northwestern Nicaragua. When the side of Casita Volcano collapsed on October 30, 1998, more than 2,000 people were killed within minutes as a large lahar swept over the towns of El Porvenir and Rolando Rodriguez. Links are also available to a photoglossary of volcanoes, a site on volcano observatories, a site describing current United States volcanic activity, and sites explaining volcano hazards, including gas, lahars, landslides and tephra.

Scott, K.; Macias, J.; Cruz, F.

261

NASA Earth Observatory: Natural Hazards  

NSDL National Science Digital Library

The purpose of NASA's Earth Observatory is to provide a freely-accessible publication on the Internet where the public can obtain new satellite imagery and scientific information about our home planet. The specific focus of this Earth Observatory website is natural hazards. Earth scientists around the world use NASA satellite imagery to better understand the causes and effects of natural hazards. The goal in sharing these images is to help people visualize where and when natural hazards occur, and to help mitigate their effects. Natural hazards that are emphasized include dust and smoke, wildfires, floods, severe storms, and volcanoes. In addition, each week the site highlights major natural hazard events occurring around the globe. Links to satellite imagery and informational text concerning the natural hazard and image interpretation are included. The site also offers a link to unique imagery, such as earthquakes, droughts, and landslides, and features the latest unique imagery events around the globe.

262

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

263

Living on Active Volcanoes - The Island of Hawaii  

NSDL National Science Digital Library

This United States Geological Survey (USGS) on-line publication highlights the volcanic hazards facing the people living on the Island of Hawaii. These hazards include lava flows, explosive eruptions, volcanic smog, earthquakes and tsunamis. This report discusses these hazards, the volcanoes of Mauna Loa and Kilauea, and the work of the Hawaiian Volcano Observatory to monitor and issue warnings to the people affected by these hazards.

Heliker, Christina; Stauffer, Peter; Hendley Ii., James

264

Earth Layers and Volcanoes  

NSDL National Science Digital Library

Why do we have volcanoes? Use the information on the websites to answer the questions on the worksheet. Worksheet First, review the layers of the earth. Labeling the layers game Next, go through the maze and read the information given. Magic School Bus volcano game Now, study the different shapes of volcanoes. Click enter, then volcano types in the menu. Read about the 3 types of volcanoes. Discovery Kids Games Finally, watch ...

Brookeshallow

2011-04-13

265

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

266

Detecting small geothermal features at Northern Pacific volcanoes with ASTER thermal infrared data  

NASA Astrophysics Data System (ADS)

The Alaska Volcano Observatory (AVO) and the Kamchatkan Volcanic Eruption Response Team (KVERT) monitor the eruptive state of volcanoes throughout the Aleutian, Kamchatkan, and Kurile arcs. This is accomplished in part by analyzing thermal infrared (TIR) data from the Advanced Very High Resolution Radiometer (AVHRR) and Moderate-resolution Imaging Spectroradiometer (MODIS) sensors at least twice per day for major thermal anomalies. The AVHRR and MODIS 1-km spatial resolution data have been very useful for detecting large and/or high-temperature thermal signatures such as Strombolian activity as well as lava and pyroclastic flows. Such anomalies commonly indicate a major eruptive event is in progress. However, in order to observe and quantify small and/or lower temperature thermal features such as fumaroles and lava domes, higher spatial resolution data with better radiometric and spectral resolution are required. We have reviewed 2600 available night and day time TIR scenes acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) over the volcanoes of the northern Pacific. The current archive spans from March, 2000 to present. ASTER is the only instrument that routinely acquires high spatial resolution (30 - 90 m) night time data over volcanic targets. These data sets typically contain 5 TIR (8-12 microns) with 90 meter spatial resolution and 6 shortwave infrared (SWIR) bands (1-3 microns) with 30 meter spatial resolution. After the general survey of the volcanic arcs, we have focused our efforts on several targets. Mt. Hague, in the Emmons Lake complex on the Alaska Peninsula, has had mostly cloud-free ASTER observations for twenty night time TIR and six daytime TIR since August 2000. A small lake in the lower crater of Mt. Hague has had a history of appearing and disappearing over the last few years. The ASTER data combined with several recent field observations allow us to track the changes in lake area and associated temperatures. With more frequent observations, we hope to determine the mechanism of these changes. The 1975-76 craters and lava flows of New Tolbachik Volcano in central Kamchatka appear as persistent thermal features in clear night time ASTER TIR data with ASTER TIR temperatures as high as 22° C. Handheld FLIR TIR images (~0.5m pixels) from August 2004 show temperatures >176° C on the lava flow and >226° C in the crater wall. Mutnovsky and Gorely Volcanoes in southern Kamchatka also have several persistent thermal features in the ASTER data from late 2001 until at least November 2003. These features correlate to a vigorous fumarole field and crater lakes. The Mutnovsky thermal features were also observed in AVHRR data by KEMSD in March, June, and July 2003. The goal of this work is to better detect changes in current volcano activity or precursors to new activity. Our ongoing survey of the ASTER TIR data has created a database of many small (<90 m) or low temperature (20 to 38° C) thermal features at several volcanoes in the northern Pacific region. We will attempt to observe each of the identified features at least annually using ASTER data as it becomes available over each target.

Wessels, R.; Senyukov, S.; Tranbenkova, A.; Ramsey, M. S.; Schneider, D. J.

2004-12-01

267

Automatic classification and a-posteriori analysis of seismic event identification at Soufrière Hills volcano, Montserrat  

Microsoft Academic Search

Seismic energy radiation at Soufrière Hills volcano, Montserrat, is made up by various types of transient signals, which are distinguished by the Montserrat Volcano Observatory (MVO) in different classes with respect to their characteristics and\\/or origin. There are five fundamental classes, i.e., Volcano-Tectonic Events, Regional Events, Long-Period Events, Hybrid Events, and Rockfalls. Identification and classification of these transients, which have

H. Langer; S. Falsaperla; T. Powell; G. Thompson

2006-01-01

268

Prototype PBO Instrumentation of CALIPSO Project Captures World-Record Lava Dome Collapse on Montserrat Volcano  

Microsoft Academic Search

This article is an update on the status of an innovative new project designed to enhance generally our understanding of andesitic volcano eruption dynamics and, specifically, the monitoring and scientific infrastructure at the active Soufriàre Hills Volcano (SHV), Montserrat. The project has been designated as the Caribbean Andesite Lava Island Precision Seismo-geodetic Observatory, known as CALIPSO. Its purpose is to

Glen S. Mattioli; Simon R. Young; Barry Voight; R. Steven J. Sparks; Eylon Shalev; Sacks Selwyn; Peter Malin; Alan Linde; William Johnston; Dannie Hadayat; Derek Elsworth; Peter Dunkley; Richard Herd; Jurgen Neuberg; Gillian Norton; Christina Widiwijayanti

2004-01-01

269

Electrifying Alaska  

Microsoft Academic Search

Alaska's diverse systems for electric power include only 4% by private utilities. Large distances and small markets make transmission impractical for the most part. Rates are variable, although the state average is low. Energy sources, except nuclear, are abundant: half the US coal reserves are in Alaska. In addition, it has geothermal, tidal, biomass, solar, wind, and hydroelectric power. Energy

Reinemer

2009-01-01

270

Explosive eruptive record in the Katmai region, Alaska Peninsula: an overview  

Microsoft Academic Search

At least 15 explosive eruptions from the Katmai cluster of volcanoes and another nine from other volcanoes on the Alaska Peninsula\\u000a are preserved as tephra layers in syn- and post-glacial (Last Glacial Maximum) loess and soil sections in Katmai National\\u000a Park, AK. About 400 tephra samples from 150 measured sections have been collected between Kaguyak volcano and Mount Martin\\u000a and

Judy Fierstein

2007-01-01

271

Virtual Observatories  

NASA Astrophysics Data System (ADS)

Astronomy has been at the forefront among scientific disciplines for the sharing of data, and the advent of the World Wide Web has produced a revolution in the way astronomers do science. The recent development of the concept of Virtual Observatory builds on these foundations. This is one of the truly global endeavours of astronomy, aiming at providing astronomers with seamless access to data and tools, including theoretical data. Astronomy on-line resources provide a rare example of a world-wide, discipline-wide knowledge infrastructure, based on internationally agreed interoperability standards.

Genova, Françoise

2011-06-01

272

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.

273

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

274

Nighttime Near Infrared Observations of Augustine Volcano Jan-Apr, 2006 Recorded With a Small Astronomical CCD Camera  

Microsoft Academic Search

Nighttime observations of Augustine Volcano were made during Jan-Apr, 2006 using a small, unfiltered, astronomical CCD camera operating from Homer, Alaska. Time-lapse images of the volcano were made looking across the open water of the Cook Inlet over a slant range of ~105 km. A variety of volcano activities were observed that originated in near-infrared (NIR) 0.9-1.1 micron emissions, which

D. Sentman; S. McNutt; C. Reyes; H. Stenbaek-Nielsen; N. Deroin

2006-01-01

275

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

276

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

277

Aerosol Lesson: Volcano Types  

NSDL National Science Digital Library

This activity has students research a list of volcanoes and then write detailed information they researched under a column that identifies that type of volcano - Cinder Cone, Composite, or Shield. Included are a worksheet and a collection of links to referential websites about specific volcanoes.

278

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

279

The Volcano Adventure Guide  

Microsoft Academic Search

Adventure travels to volcanoes offer chance encounters with danger, excitement, and romance, plus opportunities to experience scientific enlightenment and culture. To witness a violently erupting volcano and its resulting impacts on landscape, climate, and humanity is a powerful personal encounter with gigantic planetary forces. To study volcano processes and products during eruptions is to walk in the footsteps of Pliny

Fraser Goff

2005-01-01

280

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

281

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

282

Focus: alien volcanos  

NASA Astrophysics Data System (ADS)

Part 1: Volcanoes on Earth - blowing their top; Part 2: Volcanoes of the inner Solar System - dead or alive: the Moon, Mercury, Mars, Venus; Part 3: Volcanoes of the outer Solar System - fire and ice: Io, Europa, Ganymede and Miranda, Titan, Triton, Enceladus.

Carroll, Michael; Lopes, Rosaly

2007-03-01

283

Alaska Commercial Fisheries Statistics.  

National Technical Information Service (NTIS)

The following statistical reports and booklets were compiled, published, and distributed: (1) 1973 Alaska commercial fishing vessel register; (2) Weekly Alaska Salmon casepack reports; (3) Monthly Alaska shellfish reports; (4) Alaska tables for the INPFC ...

J. F. Jewell

1974-01-01

284

Continuous GPS Measurement of Deformation at Erebus Volcano, Antartica  

Microsoft Academic Search

Mt. Erebus is the most active volcano in Antarctica. It has a persistent convecting lava lake of anorthoclase phonolite magma, which has small Strombolian eruptions. Rare ash eruptions occur from adjacent vents. During the 2002\\/03 and 2003\\/04 field seasons, 4 integrated continuously telemetered geophysical observatories with dual frequency GPS were installed around the summit crater and 1 on the flank

M. H. Murray; P. R. Kyle; R. C. Aster; B. Bartel

2006-01-01

285

EarthScope: A distributed, multi-purpose geophysical observatory for the structure and dynamics of the North American continent  

NASA Astrophysics Data System (ADS)

EarthScope, a broad-based geophysics program funded by the US National Science Foundation, takes a multidisciplinary approach to studying the structure and evolution of the North American continent and the physical processes controlling earthquakes and volcanoes. The integrated observing systems that make up the EarthScope facilities provide data streams that address fundamental questions at a variety of scales including the active nucleation zone of earthquakes, individual faults and volcanoes, the deformation along the plate boundary, and the structure of the continent and planet. EarthScope data are freely and openly available to maximize participation from the national and international scientific community and to provide ongoing educational outreach to students and the public. EarthScope facilities include the San Andreas Fault Observatory at Depth (SAFOD), the Plate Boundary Observatory (PBO), and the USArray. With leadership from the U.S. academic research community, consortium members, and through collaboration with other national and international organizations, IRIS operates, maintains, and manages the USArray facility and UNAVCO manages the PBO and SAFOD facilities. USArray consists of a portable array of 400 broadband seismometers that traverse North America and Alaska over a 15- year period; a pool of broadband, short-period, and active source seismometers available for deployment in areas where a denser observations are required; and seven permanent and 20 portable magnetotelluric (MT) instruments. SAFOD consists of a 3.1 km instrumented and core-sampled borehole that crosses the seismogenic zone of the San Andreas fault, designed to directly reveal the physical and chemical processes controlling earthquake generation. The PBO is a permanent network of continuous Global Positioning System (CGPS) stations, borehole tensor strainmeters, long baseline laser strainmeters, and a pool of campaign GPS units that provide deformation data for fundamental studies of the dynamics of plate motions, earthquakes, and volcanoes. Distributed EarthScope data management systems ensure that all data collected by the USArray, PBO, SAFOD, and partner organizations are archived and distributed to the science community, educators, and the public free of charge and without delay. Our presentation will review the construction and operations of the EarthScope facility and provide science highlights that illustrate the transformational power of openly available, integrated community data sets. We will compare and contrast the EarthScope facility with other international geographically distributed Earth science observatories such as GEONET, AUscope, and EPOS.

Jackson, Mike E.; Woodward, R.

2010-05-01

286

THEMIS Ground Based Observatories  

NASA Astrophysics Data System (ADS)

A network of 20 Ground-Based Observatories (GBOs) plays a crucial role in the 5 satellite Time History of Events and Macroscale Interactions during Substorms (THEMIS) NASA mission. Each GBO will provide white-light all-sky auroral images at a 5 second cadence and geomagnetic field vectors at a minimum of 1 Hz. These data will be used in conjunction with the spacecraft observations to study the initial onset and development of the substorm process. There will be 16 GBOs in Canada and 4 in Alaska, providing more than 8 hours of local time coverage. Each site will be connected to the internet with a fallback link provided by the Iridium network. Summary data from the GBO field sites will be available in real-time and full resolution data will physically retrieved every few months. Nearly half the sites are already operational, with the remainder to be installed during the summer 2006 field season. This talk will be a review of the GBO project progress including topics such as design, construction, communications, operations and data management.

Jackel, B.; Donovan, E.; Greffen, M.; Angelopoulos, V.; Mende, S.; Harris, S.; Rachelson, W.; Russell, C.; Pierce, D.; Dearborne, D.

2005-12-01

287

Infrasonic Wave Observations of the January 2006 Augustine Volcano Eruptions  

NASA Astrophysics Data System (ADS)

The recent Augustine eruptions, from the 11th to the 28th of January 2006, have produced a series of ten infrasonic signals observed at the I53US array*. The eruption times for the signals were provided by the Alaska Volcano Observatory at UAF using a Chaparral microphone present on Augustine Island a few kilometers from the crater. The bearing and distance of Augustine from I53US are respectively: 207.8 degrees and 675 km. The analysis of the signals is done with a least-squares detector/estimator that calculates, among other things, the horizontal trace-velocity and the azimuth of arrival of the signal. The average values of the trace- velocity and azimuth for all ten Augustine signals are: 0.336 +/- 0.0136 km/sec and 208.7 +/- 1.5 deg. respectively. The celerity for each signal was calculated using the range 675 km and the individual travel times to I53US. The average celerity for all ten eruption signals was 0.287 +/- 0.018 km/sec. Ray tracing studies, using wind speed and temperature profiles supplied by Dr. Doug Drob at NRL, have shown that both stratospheric and thermospheric ray paths are present in the data set. *An eight-microphone, infrasonic array with a digital data recording system was installed in the forest north of the UAF campus in 2001 as a part of the world-wide CTBT/IMS monitoring network. The microphone array, termed I53US, is comprised of eight sensors arranged in an outer pentagon of 5 sensors with an aperture of 1.7 km and an inner triangle of three sensors with an aperture of 0.17 km. The pressure data from each sensor is digitized at 20 samples/second, time stamped with GPS time and recorded in the data base of the GI infrasound group.

Olson, J. V.; Wilson, C. R.; McNutt, S.; Tytgat, G.

2006-12-01

288

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.

289

Seismic hazards at Kilauea and Mauna Loa volcanoes, Hawaii  

NASA Astrophysics Data System (ADS)

A significant seismic hazard exists in south Hawaii from large tectonic earthquakes that can reach magnitude 8 and intensity XII. This paper quantifies the hazard by estimating the horizontal peak ground acceleration (PGA) in south Hawaii which occurs with a 90% probability of not being exceeded during exposure times from 10 to 250 years. The largest earthquakes occur beneath active, unbuttressed and mobile flanks of volcanos in their shield building stage. The flanks are compressed and pushed laterally by rift zone intrusions. The largest earthquakes are thus not directly caused by volcanic activity. Historic earthquakes (since 1823) and the best Hawaiian Volcano Observatory catalog (since 1970) under the south side of the island define linear frequency-magnitude distributions that imply average recurrence intervals for M greater than 5.5 earthquakes of 3.4-5 years, for M greater than 7 events of 29-44 years, and for M greater than 8 earthquakes of 120-190 years. These estimated recurrences are compatable with the 107 year interval between the two major April 2, 1868 (M(approximately)7.9) and November 29, 1975 (M=7.2) earthquakes. Frequency-magnitude distributions define the activity levels of 19 different seismic source zones for probabilistic ground motion estimations. The available measurements of PGA (33 from 7 moderate earthquakes) are insufficient to define a new attenuation curve. We use the Boore et al. (1993) curve shifted upward by a factor of 1.2 to fit Hawaiian data. Amplification of sites on volcanic ash or unconsolidated soil are about two times those of hard lava sites. On a map for a 50 year exposure time with a 90% probability of not being exceeded, the peak ground accelerations are 1.0 g Kilauea's and Mauna Loa's mobile south flanks and 0.9 g in the Kaoiki seismic zone. This hazard from strong ground shaking is comparable to that near the San Andreas Fault in California or the subduction zone in the Gulf of Alaska.

Klein, Fred W.

1994-04-01

290

Volcano Seismology  

NASA Astrophysics Data System (ADS)

- A fundamental goal of volcano seismology is to understand active magmatic systems, to characterize the configuration of such systems, and to determine the extent and evolution of source regions of magmatic energy. Such understanding is critical to our assessment of eruptive behavior and its hazardous impacts. With the emergence of portable broadband seismic instrumentation, availability of digital networks with wide dynamic range, and development of new powerful analysis techniques, rapid progress is being made toward a synthesis of high-quality seismic data to develop a coherent model of eruption mechanics. Examples of recent advances are: (1) high-resolution tomography to image subsurface volcanic structures at scales of a few hundred meters; (2) use of small-aperture seismic antennas to map the spatio-temporal properties of long-period (LP) seismicity; (3) moment tensor inversions of very-long-period (VLP) data to derive the source geometry and mass-transport budget of magmatic fluids; (4) spectral analyses of LP events to determine the acoustic properties of magmatic and associated hydrothermal fluids; and (5) experimental modeling of the source dynamics of volcanic tremor. These promising advances provide new insights into the mechanical properties of volcanic fluids and subvolcanic mass-transport dynamics. As new seismic methods refine our understanding of seismic sources, and geochemical methods better constrain mass balance and magma behavior, we face new challenges in elucidating the physico-chemical processes that cause volcanic unrest and its seismic and gas-discharge manifestations. Much work remains to be done toward a synthesis of seismological, geochemical, and petrological observations into an integrated model of volcanic behavior. Future important goals must include: (1) interpreting the key types of magma movement, degassing and boiling events that produce characteristic seismic phenomena; (2) characterizing multiphase fluids in subvolcanic regimes and determining their physical and chemical properties; and (3) quantitatively understanding multiphase fluid flow behavior under dynamic volcanic conditions. To realize these goals, not only must we learn how to translate seismic observations into quantitative information about fluid dynamics, but we also must determine the underlying physics that governs vesiculation, fragmentation, and the collapse of bubble-rich suspensions to form separate melt and vapor. Refined understanding of such processes-essential for quantitative short-term eruption forecasts-will require multidisciplinary research involving detailed field measurements, laboratory experiments, and numerical modeling.

Chouet, B.

291

Volcano Hazards Program Webcams  

MedlinePLUS Videos and Cool Tools

... USDA Forest Service - Mount St. Helens Crater Redoubt, Alaska (AVO), approximately 7.5 mi (12 km) from ... view of the north flank of Redoubt. Redoubt, Alaska (AVO), approximately 38 miles SE of Mt. Spurr ...

292

Publications of the Volcano Hazards Program 2005  

USGS Publications Warehouse

The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic Hazards Assessments subactivity as funded by Congressional appropriation. Investigations are carried out in the Geology and Hydrology Disciplines of the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute, University of Hawaii Hilo, University of Utah, and University of Washington Geophysics Program. This report lists publications from all these institutions. This report contains only published papers and maps; numerous abstracts produced for presentations at scientific meetings have not been included. Publications are included based on date of publication with no attempt to assign them to Fiscal Year.

Nathenson, Manuel

2007-01-01

293

The USGS Geomagnetism Program Observatory Network  

NASA Astrophysics Data System (ADS)

The mission of the U.S. Geological Survey's Geomagnetism Program is to monitor the Earth's magnetic field. Using ground-based observatories, the Program provides continuous records of magnetic field variations covering long timescales, ranging from seconds to over a century. The Program disseminates magnetic data to various governmental, academic, and private institutions; it conducts research into the nature of geomagnetic variations for purposes of scientific understanding and hazard mitigation. The Program is an integral part of the U.S. Government's National Space Weather Program. In this presentation, we summarize recent operational accomplishments of the USGS Geomagnetism Program, including the addition of a real-time one-second data product, development of quasi-definitive data from selected observatories, and improvements to the magnetic observatory network in Alaska.

Finn, C. A.

2011-12-01

294

Constraints on the geometry of the magma chamber of Mauna Loa volcano, Hawaii, from InSAR data  

Microsoft Academic Search

A period of inflation of Mauna Loa volcano has started in May 2002. Since the beginning of the inflation period the GPS network of the Hawaiian Volcano Observatory has detected a total shortening of ~25 cm of a baseline across the summit caldera. The inflation of the volcanic edifice is commonly explained by the intrusion of new magma into a

F. Amelung; T. Walter

2004-01-01

295

Spaceborne and field-based observations of Bezymianny Volcano, Kamchatka from 2000- 2008  

NASA Astrophysics Data System (ADS)

Bezymianny is a very active stratovolcano located on the Kamchatka Peninsula, Russia. It is andesitic in magma composition and typically erupts one to two times per year. The aim of this study was to ascertain background thermal conditions, attempt to locate any thermal precursory signals, and investigate the deposition and cooling of pyroclastic flow deposits that are typically emplaced on the south-eastern flank. Block and ash samples were collected and analyzed using Scanning Electron Microscope (SEM) images and thermal infrared (TIR) spectroscopy to estimate the surface vesicularity of the blocks and ash within the deposit. In addition, data from the March 2000, January 2005, December 2006, October 2007, and August 2008 explosive eruptions have been collected using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with limited field-based ground studies. According to the Kamchatkan Volcanic Eruption Response Team (KVERT) and the Alaska Volcano Observatory (AVO), another explosive eruption occurred at Bezymianny Volcano on 19 August 2008 around 10:30 UTC. A clear linear thermal anomaly was observed oriented to the southeast at the lava dome in rapid-response night time ASTER data acquired on 26 August. Preliminary results show that the maximum temperature recorded was 51.6 C (52 C above background). This likely corresponded to a short (1.3 km) lava lobe that was emplaced within a pre- existing channel. Further to the southeast, a significant thermal anomaly was observed with temperatures reaching 21 C within the centre of the anomaly, due to a warm pyroclastic flow (PF) that travelled 4.8 km from the summit. This work highlights the utility of TIR data in combination with field studies (where possible) over a highly changeable, active volcanic region and continues to stress the critical need for high spatial and temporal resolution data in Kamchatka specifically and in the North Pacific region in general.

Carter, A.; Ramsey, M.; Girina, O.; Belousov, A.; Durant, A.; Skilling, I.; Wolfe, A.

2008-12-01

296

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

297

The Anatahan volcano-monitoring system  

NASA Astrophysics Data System (ADS)

A real-time 24/7 Anatahan volcano-monitoring and eruption detection system is now operational. There had been no real-time seismic monitoring on Anatahan during the May 10, 2003 eruption because the single telemetered seismic station on Anatahan Island had failed. On May 25, staff from the Emergency Management Office (EMO) of the Commonwealth of the Northern Mariana Islands and the U. S. Geological Survey (USGS) established a replacement telemetered seismic station on Anatahan whose data were recorded on a drum recorder at the EMO on Saipan, 130 km to the south by June 5. In late June EMO and USGS staff installed a Glowworm seismic data acquisition system (Marso et al, 2003) at EMO and hardened the Anatahan telemetry links. The Glowworm system collects the telemetered seismic data from Anatahan and Saipan, places graphical display products on a webpage, and exports the seismic waveform data in real time to Glowworm systems at Hawaii Volcano Observatory and Cascades Volcano Observatory (CVO). In early July, a back-up telemetered seismic station was placed on Sarigan Island 40 km north of Anatahan, transmitting directly to the EMO on Saipan. Because there is currently no population on the island, at this time the principal hazard presented by Anatahan volcano would be air traffic disruption caused by possible erupted ash. The aircraft/ash hazard requires a monitoring program that focuses on eruption detection. The USGS currently provides 24/7 monitoring of Anatahan with a rotational seismic duty officer who carries a Pocket PC-cell phone combination that receives SMS text messages from the CVO Glowworm system when it detects large seismic signals. Upon receiving an SMS text message notification from the CVO Glowworm, the seismic duty officer can use the Pocket PC - cell phone to view a graphic of the seismic traces on the EMO Glowworm's webpage to determine if the seismic signal is eruption related. There have been no further eruptions since the monitoring system was installed, but regional tectonic earthquakes have provided frequent tests of the system. Reliance on a Pocket PC - cell phone requires that the seismic duty officer remain in an area with cell phone coverage. With this monitoring method, the USGS is able to provide rapid notice of an Anatahan eruption to the EMO and the Washington Volcano Ash Advisory Center. Reference Marso, J.N., Murray, T.L., Lockhart, A.B., Bryan, C.J., Glowworm: An extended PC-based Earthworm system for volcano monitoring. Abstracts, Cities On Volcanoes III, Hilo Hawaii, July 2003.

Marso, J. N.; Lockhart, A. B.; White, R. A.; Koyanagi, S. K.; Trusdell, F. A.; Camacho, J. T.; Chong, R.

2003-12-01

298

Sizes of Conical Volcanoes  

Microsoft Academic Search

THE shield volcano Mauna Loa in Hawaii is the world's highest mountain, 9,144 m high1, if the portion below sea level is considered in addition to the exposed 4,170 m. Why, then, are the world's highest mountains not land volcanoes? We have investigated the heights and volumes of land volcanoes to try to establish what factors prevent their development to

P. W. Francis; B. M. Abbott

1973-01-01

299

Mud volcanoes on Mars?  

NASA Astrophysics Data System (ADS)

The term mud volcano is applied to a variety of landforms having in common a formation by extrusion of mud from beneath the ground. Although mud is the principal solid material that issues from a mud volcano, there are many examples where clasts up to boulder size are found, sometimes thrown high into the air during an eruption. Other characteristics of mud volcanoes (on Earth) are discussed. The possible presence of mud volcanoes, which are common and widespread on Earth, on Mars is considered.

Komar, Paul D.

1991-06-01

300

Geologic map of the Gulkana B-1 quadrangle, south-central Alaska  

SciTech Connect

The quadrangle includes the Capital Mountain Volcano and the northern part of Mount Sanford Volcano in the Wrangell Mountains of south-central Alaska. The Capital Mountain volcano is a relatively small, andesitic shield volcano of Pleistocene age, which contains a 4-km-diameter summit caldera and a spectacular post-caldera radial dike swam. Lava flows from the younger Pleistocene Mount Sanford Volcano overlap the south side of the Capital Mountain Volcano. Copper-stained fractures in basaltic andesite related to a dike-filled rift of the North Sanford eruptive center are the only sign of mineralization in the quadrangle. Rock glaciers, deposits of Holocene and Pleistocene valley glaciers and Pleistocene Copper River basin glaciers mantle much of the volcanic bedrock below elevations of 5,500 ft.

Richter, D.H.; Ratte, J.C.; Schmoll, H.R.; Leeman, W.P.; Smith, J.G.; Yehle, L.A.

1989-01-01

301

Anatomy of a Volcano  

NSDL National Science Digital Library

This interactive from NOVA Online provides a detailed look at the inner workings of one of the world's most dangerous volcanoes, Nyiragongo in the Democratic Republic of Congo. Users can click on highlighted points on a crossection of the volcano to see photos and read about its features and eruptive products.

302

Chaiten Volcano Still Active  

NSDL National Science Digital Library

This Boston Globe news article shows 12 stunning pictures of the Chaiten Volcano erupting in Chile, its first activity in over 9,000 years. The most recent eruptive phase of the volcano began on May 2, 2008, and is ongoing. The site also has a blog of open, public commentary.

303

Mud Volcanoes on Mars.  

National Technical Information Service (NTIS)

The term mud volcano is applied to a variety of landforms having in common a formation by extrusion of mud from beneath the ground. Although mud is the principal solid material that issues from a mud volcano, there are many examples where clasts up to bou...

P. D. Komar

1991-01-01

304

Groundwater at Mayon, Volcano  

Microsoft Academic Search

Around Mayon Volcano, Philippines, anecdotal evidence and rainfall normalized spring discharge data suggest that the water table 8 km from the summit of the volcano drops prior to eruptions. Residents report that they had to deepen their shallow wells in 1993 (some before and others following the eruption). In some cases they had to dig as far as 5 meters

S. E. Albano; T. Sandoval; R. Toledo

2001-01-01

305

Astronomical Observatories in Kazakhstan  

NASA Astrophysics Data System (ADS)

A short description of three astronomical observatories of Kazakhstan situated in the northern Tien-Shan mountains is given, including instrumentation, scientific research directions and climate conditions. The observatories may be considered as convenient sites for WET observations.

Mironov, A. V.; Tereshchenko, V. M.

1998-03-01

306

‘New’ Antarctic volcanos  

NASA Astrophysics Data System (ADS)

Two previously unknown volcanos that show evidence o f recent eruptions were discovered in March on the east side of the Antarctic Peninsula, according to the National Science Foundation. The discovery brings to five the number of known active volcanos on the continent.Volcanic debris still covers a large swath of the adjacent Larsen Ice Shelf, pointing to very recent activity. In addition, one of the volcanos was steaming when the discovery was made, reports Oscar Gonzalez-Ferran of the University of Chile at Santiago. He made the discovery while doing a geophysical survey by helicopter of the Antarctic Peninsula. The two volcanos constitute the southernmost extension of the eastern side of the ‘ring of fire,’ a ring of volcanos that is believed to mark the active subduction zone on the periphery of the Pacific Ocean.

307

The La Silla Observatory  

NSDL National Science Digital Library

This European Southern Observatory website features the La Silla Observatory's latest news, telescopes, and observation reports. Visitors can find sun and moon tables, a meteorological monitor, and satellite maps. Students can learn how the mountain's geologic and geographic features impact observational abilities. Researchers can find out about visiting the Observatory and how to apply to use the observation equipment. Everyone can view amazing images of La Silla's Chilean landscape and the Observatory's facilities.

308

Brooks Astronomical Observatory  

NSDL National Science Digital Library

The Brooks Astronomical Observatory, located at Central Michigan University, was built for research and public use. The website presents the history of the Observatory and its technological capabilities. Users can find a long list of scientific publications based on research performed at the observatory. The numerous astronomical topics researched include asteroids, stellar clusters, occultations, and light pollution. Individuals can view fantastic images of comets, planets, and other space phenomena collected at the Observatory.

309

Magnetic Observatories of Kazakhstan.  

National Technical Information Service (NTIS)

In April of 1963, the first magnetic observatory in Kazakhstan began operating in the region of Alma Ata (Yu. D. Kalinin, 1957). The Karaganda Magnetic Observatory began operating in July of 1964, while the third magnetic observatory in Kazakhstan, at Kaz...

K. D. Kanonidi F. N. Yanatkhanov

1968-01-01

310

Okayama Astrophysical Observatory  

NASA Astrophysics Data System (ADS)

The Okayama Astrophysical Observatory (OAO) is a branch Observatory of the NATIONAL ASTRONOMICAL OBSERVATORY, JAPAN. Its main facilities are 188 cm and 91 cm telescopes, equipped with newly built instruments with CCD/IR cameras (e.g. OASIS). OAO accepts nearly 300 astronomers a year, according to the observation program scheduled by the committee....

Murdin, P.

2000-11-01

311

Optimized Autonomous Space In-situ Sensor-Web for Volcano Monitoring  

Microsoft Academic Search

In response to NASA's announced requirement for Earth hazard monitoring sensor-web technology, a multidisciplinary team involving sensor-network experts (Washington State University), space scientists (JPL), and earth scientists (USGS cascade volcano observatory (CVO)), is developing a prototype dynamic and scaleable hazard monitoring sensor-web and applying it to volcano monitoring. The combined optimized autonomous space - in-situ sensor-web (OASIS) will have two-way

Wen-Zhan Song; Behrooz Shirazi; Renjie Huang; Mingsen Xu; Nina Peterson; Rick LaHusen; John Pallister; Dan Dzurisin; S. Moran; M. Lisowski; Aaron Kiely; Joshua Doubleday; Ashley Davies; David Pieri

2008-01-01

312

The NASA ASTER Urgent Request Program: The Last Eight Plus Years of Monitoring Kamchatka's Volcanoes From Space  

NASA Astrophysics Data System (ADS)

From soon after its launch in December 1999, the ASTER sensor on the NASA Terra satellite has been acquiring data of volcanic eruptions and other natural disasters around the world. ASTER has the capability to acquire high spatial resolution data from the visible to thermal infrared wavelength region. Those data, in conjunction with its ability to generate digital elevation models (DEMs), makes ASTER particularly useful for numerous aspects of volcanic remote sensing. However, the nature of the ASTER scheduling/data collection/calibration pathway makes rapid observations of hazard locations nearly impossible. The sensor's acquisitions are scheduled in advance and the data are processed and calibrated in Japan prior to archiving in the United States. This can produce a lag of at least several days from the initial request to data scheduling and another several days after acquisition until the data are available. However, there exists a manual "rapid response" mode that provides faster data scheduling, processing and availability. This mode has now been semi-automated and linked to larger-scale and more rapid monitoring alert system. The first phase has been to integrate with the Alaska Volcano Observatory's current near-real-time satellite monitoring system, which relies on high temporal/low spatial resolution orbital data. This phase of the project has focused on eruptions in the north Pacific region, and in particular over Kamchatka, Russia. Several beneficial factors have combined that resulted in over 1350 ASTER images being acquired for the five most thermally-active Kamchatka volcanoes (Bezymianny, Karimsky, Kluichevskoi, Sheveluch and Tolbachik). These factors include the orbital alignment of Terra, the high latitude of the peninsula, and the many eruptions and volcanic activity in Kamchatka. From the inception of the automated rapid response program in 2003, an additional 350 scenes have been acquired over the Kamchatka volcanoes, which have targeted both small-scale activity and larger eruptions for science and hazard response. Numerous eruptions have been observed that displayed varying volcanic styles including basaltic lava flow emplacement, silicic lava dome growth, pyroclastic flow production, volcanic ash plume production, fumarolic activity, and geothermal emission. The focus of this presentation is to summarize the current ASTER rapid response program in Kamchatka, focus on two specific eruptions of Sheveluch volcano, and discuss the future expansion plans for global hazard response.

Ramsey, M.; Wessels, R.; Dehn, J.; Duda, K.; Harris, A.; Watson, M.

2008-12-01

313

Communicating Ash-Fall Hazard to the Public During Eruptions: A Proposed Scheme to Streamline Ash-Fall Warning Messages in the U.S. Based on the Recent Activity at Augustine Volcano, Alaska  

NASA Astrophysics Data System (ADS)

The recent eruption of Augustine Volcano resulted in <1 mm of ash fall on populated areas following 13 brief, vulcanian explosions. Anticipated ash fall prompted several school and office closures, a high degree of concern in parts of the Kenai Peninsula and as far away as Anchorage, and pre-emptive rerouting of jet aircraft. In hindsight, some over-reaction to the actual ash-fall hazard underscored (1) deficiencies in the abilities of volcanologists and meteorologists to rapidly convey (in words and graphics) the expected accumulation of ash downwind; (2) limitations in real-time forecasting of the motion and density of dispersed, distal volcanic clouds hours to days after an eruption; and (3) weaknesses in official warning message form, content, and protocols. The first two topics are targets of vigorous and needed research and development. Here, we discuss the literal effectiveness of official ash fall warnings. The rarity of ash fall events in the U.S. has contributed to a lack of standardized public warning messages and guidance issued by the National Weather Service, the U.S. Geological Survey, local departments of health and environmental quality, municipalities, and other agencies. To effectively communicate information about ash- fall hazards, agencies require more rigorous, predetermined criteria to quickly generate appropriate warning product types that contain specific descriptions and mitigation guidance. We propose a matrix of ash-fall severities (e.g. trace, light, medium, heavy) that can be used in standard messages with each term linked to specific impacts and `call to action' statements. Increasing severity of anticipated or actual ash fall would prompt (in order of accelerating concern) Public Weather Statements, Ash Fall Advisories, Ash Fall Warnings or other products as appropriate. We use expected accumulation (total thickness) as the primary criteria rather than accumulation rate or airborne particulate concentration which are more challenging to estimate and understand. Clearly, impacts from various ash falls will vary widely with local conditions, hence such matrices can be tailored for regional use.

Neal, C.; Wallace, K.; Albanese, S.; Fish, A.; Cahill, C.

2006-12-01

314

Transient signal detection using GPS measurements: Application of PBO data in Alaska  

NASA Astrophysics Data System (ADS)

Continuous Global Positioning System (GPS) networks record station position changes with an accuracy of a few millimeters and have revealed transient deformations on various spatial and temporal scales. However, the transient deformation may not be easily identified from the position time series because of the large number of sites in a network, low signal-to-noise ratios (SNR) and correlations between position measurements in space and time. We have developed an algorithm for detecting transient signals based on state estimation in Kalman filter formulations and principal component analysis (PCA). The state estimation enhances the SNR by reducing white noise and estimating time-correlated noise. The space-correlated noise can be suppressed by realizing a regional reference frame. Then we use PCA to search for coherent signals in the large size of data based on the variance-covariance structure of data. Here we apply the detection algorithm to the daily GPS position time series measured in Alaska sites of the Plate Boundary Observatory (PBO) network. We found a transient signal, which is not apparent in raw daily time series, occurred at Akutan volcano during the first half of 2008. The Akutan sites moved outward from the center of the volcano with the maximum amplitude of ~ 8.5 mm, which may be related to a magnitude 6.4 earthquake that occurred about 250 km away shortly before the transient onset. The detection algorithm improves the SNR and therefore provides much higher resolution for detecting transient signals that may be even below noise level.

Ji, K.; Herring, T.

2010-12-01

315

Observatory Publications --- Quo Vadis?  

NASA Astrophysics Data System (ADS)

In the first part we discuss briefly the history of observatory publications. Then we express our opinion about the role and value of observatory publications as an inexpensive means of information exchange. We think that observatory publications should be preserved on the web, and we argue that the tradition of observatory publications should be continued. The web could provide the effective means for circulation. Moreover, we introduce the idea of preserving the contents of observatory web sites in the form of observatory publications in linear text form, bound to finite volumes, and numbered as a part of a series (note that this does not necessarily involve paper). Observatories should cooperate with databases since they would need methodological help; standards should be strengthened; and the community of astronomy libraries should take part in this effort. The slides of the talk are available: Quo Vadis slides .

Holl, András; Vargha, Magda

316

UAFSmoke Modeling in Alaska  

Microsoft Academic Search

Alaska wildfires have strong impact on air pollution on regional Arctic, Sub-Arctic and even hemispheric scales. In response to a high number of wildfires in Alaska, emphasis has been placed on developing a forecast system for wildfire smoke dispersion in Alaska. We have developed a University of Alaska Fairbanks WRF\\/Chem smoke (UAFSmoke) dispersion system, which has been adapted and initialized

M. Stuefer; G. Grell; S. Freitas; G. Newby

2008-01-01

317

THE GEOLOGIC RISK IN THE LAKE KIVU BASIN AREA PRODUCTED BY EARTHQUAKES. Case of the February 3th 2008 earthquake. By: L.M.Bagalwa(1), F.Lukaya(1), M.Burume(2), J.Moeyerson(3) (1): Goma Volcano Observatory, D.R.Congo (2): Naturals Sciences Research Center  

NASA Astrophysics Data System (ADS)

The eastern Democratic Republic of Congo is prone to earthquakes of magnitude greater than or equal to 4 on the Richter scale. The western edge of Lake Kivu, the most populated part of the region is no exception to the solicitation of these earthquakes. Since 1997, the western basin of Lake Kivu is experiencing intense seismicity, several earthquakes of great intensity, magnitude greater than or equal to 4 develop major destructive phenomena. These include the 1997 earthquake (M = 4.7) 2000 (M = 4.6 and 5.4), 2002 (M = 4.9, 5.2, 6.1 and 24 October 2002 M = 6.2) of February 3rd 2008 (M = 6). Earthquakes of Kalehe on October 24th 2002 and Birava, February 3rd 2008 have resulted deformations of soil, human and material damage. This latest natural disaster ever known in the south-western basin of Lake Kivu has attracted our scientific curiosity we go there to inquire into its causes and consequences in this region. The basin of Lake Kivu is affected by transform faults emerging (MUKONKI & CHOROWICZ, 1980, quoted by K.S.KAVOTHA & ali, 1990) that delimit the Rift were intersecting at the level of Lake Kivu. We Consider the seismicity, volcanism and uplift of the basin of Lake Kivu as a sign of fracturing under way to delimit a plate tectonics formed (Wong and Von Herzen, 1974, quoted by KSKAVOTHA et al, 1990). The physiography of Lake Kivu is dominated by the fault which borders the western shore and one which intersects the island of Idjwi. The telemetry data of Goma Volcano Observatory added to those of the seismographic station of Lwiro have always revealed a pattern of epicenters clearer in Lake Kivu. In correlation with the faults of the region, earthquakes affect mainly the western edge of Lake Kivu and the island of Idjwi with increasing density from north to south (K.S.KAVOTHA et al, 1990). The great earthquake of Lake Kivu basin on February 03rd 2008, of magnitude 6 on the Richter scale occurred at 07 hours 34 minutes 12 seconds GMT, about 20 km north of Bukavu, 80km south-west of Goma, between 02,314S and 028,896E, at a depth of 10km epicentral surface. Three major aftershocks followed to this great earthquake and were recorded at the seismographic station of Lwiro and the Goma Volcano Observatory: 1. The first after shock at 10 hours 56minutes 10seconds AM GMT, of magnitude 5.0, located at 20km depth and oriented on the north-east of Bukavu and 80km depth on the west of Butare in Rwanda between 02.456 S and 029.039 E. 2. The second after shock at 11 hours 07 minutes AM GMT, of magnitude 4.7, located at 25km depth on the north-east of Bukavu and 75 km depth on the south-west of Goma, between 02.307S and 028.997E. 3. The third after shock at 11hours 37minutes 49secondes AM GMT, of magnitude 4.5, located at 40km depth on the west of Butare in Rwanda and 55km depth on the east of Bukavu between 02.525S and 029.363E (Lukaya N'yombo Fr,11 February 2008). Other after shocks not indicated in this text was shacked the western of Lake Kivu basin. This great earthquake and its first two aftershocks were located in the south western of Lake Kivu basin, in Ishungu and Birava region in territory of Kabare. The damage is observed on a radius of approximately 20 km. This earthquake has reactivated the faults along the western shore of the Lake Kivu, but also those of the Fomulac-Kakondo-Ishungu-Birava axis. Those in Bukavu town, the South and North direction have not escaped at this reactivation. The movement of these faults has caused deformations in the surface soil and buildings erected on these flaws have suffered cracks and destruction. We will present damages of this natural risk in our poster presentation.

Bagalwa Rukeza, Montfort

2010-05-01

318

Pavlof Volcano From Station  

NASA Website

Astronauts aboard the International Space Station (ISS) photographed this striking view of Pavlof Volcano on May 18, 2013. The oblique perspective from the ISS reveals the three dimensional structure of the ash plume, which is often obscured by the ...

319

VALVE: Volcano Analysis and Visualization Environment  

NASA Astrophysics Data System (ADS)

Modern volcano observatories collect data using a wide variety of instruments. Visualizing these disparate data on a common time base is critical to interpreting and reacting to geophysical changes. With this in mind, the Hawaiian Volcano Observatory (HVO) created Valve, the Volcano Analysis and Visualization Environment. Valve integrates a wide range of both continuous and discontinuous data sources into a common, internet web-browser based interface that allows scientists to interactively select and visualize these data on a common time base and, if appropriate, in three dimensions. Advances in modern internet browser technology allow for a truly interactive user-interface experience that could previously only be found in stand-alone applications--all while maintaining client platform independence and network portability. This system aids more traditional in-depth analysis by providing a common front-end to retrieving raw data. In most cases, the raw data are being served from an SQL database, a system that lends itself to quickly retrieving, logically arranging, and safely storing data. Beyond Valve's visualization capabilities, the system also provides a variety of tools for time series analysis and source modeling. For example, a user could load several tilt and GPS time series, estimate co-seismic or co-intrusive deformation, and then model the event with an elastic point source or dislocation. From the source model, Coulomb stress changes could be calculated and compared to pre- and post-event hypocenter distribution. Employing a heavily object-oriented design, Valve is easily extensible, modular, portable, and remarkably cost efficient. Quickly visualizing arbitrary data is a trivial matter, while implementing methods for permanent, continuous data streams requires only minimal programming. Portability is ensured by using software that is readily available on a wide variety of operating systems; cost efficiency is achieved by using software that is open-source and/or available free of charge.

Cervelli, D. P.; Cervelli, P.; Miklius, A.; Krug, R.; Lisowski, M.

2002-12-01

320

Introduction to Special Section on How Volcanoes Work: Part 3  

NASA Astrophysics Data System (ADS)

The nine papers in this issue represent the third, and final, part of the special section on "How Volcanoes Work." Part 1 of this special section was published in the December 1987 [Tilling, 1987] and part 2 in May 1988 [Tilling, 1988] all three parts will be published together as a separate volume titled "How Volcanoes Work" by the American Geophysical Union. In its entirety, the special section gives a good sampling of the nearly 300 papers presented at an international symposium of the same name held in Hilo, Hawaii, in January 1987 in commemoration of the Diamond Jubilee (75th Anniversary) of the founding of the Hawaiian Volcano Observatory [Wright and Decker, 1987]. The breadth of topics covered in all three parts of the special section (Table 1) amply attests to the multidisciplinary nature of modern studies of volcanic phenomena. Collectively, these studies also comprise a most fitting tribute to Thomas A. Jaggar, Jr., who founded the Hawaiian Volcano Observatory in 1912 and was a dominant force in quantifying the science of volcanology. Not only was Jaggar a scientific visionary, but he also stressed that the scientific knowledge on volcanoes must be applied to reduce death and destruction from volcanic hazards. It is clear from the papers contained in the special section of the Journal of Geophysical Research that great strides have been made in our scientific understanding of how volcanoes work since Jaggar's time. But the destructive eruptions at Mount St. Helens (United States, May 1980), E1 Chichón (Mexico, March-April 1982), and Nevado del Ruiz (Colombia, November 1985), each causing the worst volcanic disaster in the recorded history of each of these countries [Tilling and Newhall, 1987] are tragic reminders that commensurate advances in reducing volcanic risk on a global basis have not yet been achieved.

Tilling, Robert I.

1988-12-01

321

Volcano Watch Satellite Images  

NSDL National Science Digital Library

The University of Wisconsin's Space Science and Engineering Center displays these satellite images of the world's ten most active volcanoes. Users can view images of the Colima Volcano in Central Mexico or Mount Etna in Sicily, Italy. The latest images are updated every half-hour. Also, a Java animation feature splices together the last four images to show a simulation over a two-hour period.

322

Volcano Monitoring Techniques  

NSDL National Science Digital Library

This site introduces the several methods geologists use to monitor changes in a volcano. These methods assist in forecasting intrusions and eruptions and consist of ground movements, seismicity, gas geochemistry, and geology. As a result of this lesson, students will realize that eruptions have precursor activities, recognize patterns in volcano behavior, and interpret graphical data. This site includes fifteen activities that range from kindergarten to the twelfth grade level and include required material and worksheets.

323

Assessing Volcanic Threat and Prioritizing Volcano Monitoring in the United States  

NASA Astrophysics Data System (ADS)

A methodology to characterize and rank volcanic threat was developed to prioritize monitoring improvements on a national scale. 169 Holocene-age U.S. volcanoes are ranked by level of threat based on scoring of various hazard factors (for example, explosivity, frequency of eruptions) and exposure factors (for example, nearby population and infrastructure, aviation) that were chosen to give a balanced view of unmitigated volcanic threat. For each volcano, the sum of its hazard score times the sum of its exposure score gives a numerical threat score. The distribution of scores for all 169 volcanoes defines five threat groups ranging from Very High to Very Low. Higher-threat volcanoes warrant better early-warning monitoring capability than lower-threat volcanoes. Accordingly, the adequacy of the current monitoring level at each volcano is rated on our ability to characterize ongoing and expected activity based on the types, numbers, and location of monitoring instrumentation now in place at each. The current monitoring level is compared to the level warranted by a volcano's threat score to determine if it has a significant "monitoring gap". The gap analysis systematically identifies hazardous volcanoes where monitoring is inadequate for the threats posed such as in the Cascade Range. This analysis also highlights serious monitoring inadequacies in Alaska and the Northern Marianas where the volcanic-ash hazard to aviation is high yet numerous volcanoes have no monitoring whatsoever; from a hazards perspective these regions can no longer be considered remote. The results of the U.S. volcanic threat assessment are being used to guide long-term improvements to the national volcano-monitoring infrastructure operated by the USGS and affiliated partners and to establish a National Volcano Early Warning System. Given the time required to install instrumentation and telemetry in volcanic areas and the need to provide reliable scientific interpretation of the progression of unrest, improvements need to be implemented well in advance the onset of unrest.

Ewert, J. W.; Guffanti, M.; Murray, T. L.

2005-12-01

324

Volcanoes: Coming Up from Under.  

ERIC Educational Resources Information Center

|Provides specific information about the eruption of Mt. St. Helens in March 1980. Also discusses how volcanoes are formed and how they are monitored. Words associated with volcanoes are listed and defined. (CS)|

Science and Children, 1980

1980-01-01

325

INTERMAGNET and magnetic observatories  

USGS Publications Warehouse

A magnetic observatory is a specially designed ground-based facility that supports time-series measurement of the Earth’s magnetic field. Observatory data record a superposition of time-dependent signals related to a fantastic diversity of physical processes in the Earth’s core, mantle, lithosphere, ocean, ionosphere, magnetosphere, and, even, the Sun and solar wind.

Love, Jeffrey J.; Chulliat, Arnaud

2012-01-01

326

A new organization to improve coordination of U.S. volcano monitoring  

NASA Astrophysics Data System (ADS)

With nearly 70 active and potentially active volcanoes in five distinct tectonic settings, the United States is a volcanically vigorous country that repeatedly experiences significant levels of volcanic unrest and eruptive activity. Five interactive volcano observatories, supported mainly by the Volcano Hazards Program of the U.S. Geological Survey (USGS), conduct long-term monitoring and associated research investigations (see text box). In addition,through a joint program of USGS and the U.S. Agency for International Development, some volcanoes in other countries are visited—by invitation— by rapid-response teams of U.S. volcanologists who assist with monitoring and hazard assessment during periods of unrest or eruption.Monitoring operations at the volcano observatories are a cooperative undertaking, carried out using staff and facilities of USGS, and of partners at other federal and state agencies and at universities (These are partnerships that are formalized through Memoranda of Understanding, Congressional directive, or long-standing cooperative agreements with USGS.) The dispersed geographic and institutional nature of the observatory activities requires substantial interaction among all the scientific partners to achieve the desired level of cooperation.

Guffanti, Marianne

327

Mauna Loa volcano is not a methane source: Implications for Mars  

Microsoft Academic Search

Thirteen years of continuous atmospheric carbon dioxide and methane measurements at the Mauna Loa Observatory in Hawaii are used to determine the methane emission rate from the summit of Mauna Loa volcano. We find no measurable methane emissions coming from the summit area, with a 95% confidence upper limit of 9 t CH4 yr?1. Recent studies have detected 10 ppb

Steven Ryan; Edward J. Dlugokencky; Pieter P. Tans; Michael E. Trudeau

2006-01-01

328

A reinterpretation of seismicity associated with the January 1983 dike intrusion at Kilauea Volcano, Hawaii  

Microsoft Academic Search

In January 1983, a dike intrusion\\/fissure eruption generated a swarm of 375 magnitude 1 to 3 earthquakes along a 16-km segment of Kilauea's Middle East Rift Zone. We searched the Hawaiian Volcano Observatory catalog for multiples of similar events from this region from 1980 through 1985 and obtained precise relative locations by waveform cross correlation. Over 150 of the intrusion

Allan M. Rubin; Dominique Gillard; Jean-Luc Got

1998-01-01

329

Feasible study on the integration system for the space monitoring of major earthquakes and volcanoes in terrestrial land  

Microsoft Academic Search

With the rapid development of space technology, earth observation technology and sky observatory technology, they have played\\u000a a more and more important part in monitoring and predicting of earthquakes and volcanoes in the terrestrial land. In recent\\u000a years, the related agencies have done the experiments and researches on monitoring and predicting of earthquakes and volcanoes\\u000a in the forewarning period by

Li-qun Bo

2002-01-01

330

CALIPSO Borehole Instrumentation Project at Soufriere Hills Volcano, Montserrat, BWI: Data Acquisition, Telemetry, Integration, and Archival Systems  

Microsoft Academic Search

The CALIPSO Project (Caribbean Andesite Lava Island-volcano Precision Seismo-geodetic Observatory) has greatly enhanced the monitoring and scientific infrastructure at the Soufriere Hills Volcano, Montserrat with the recent installation of an integrated array of borehole and surface geophysical instrumentation at four sites. Each site was designed to be sufficiently hardened to withstand extreme meteorological events (e.g. hurricanes) and only require minimum

G. S. Mattioli; A. T. Linde; I. S. Sacks; P. E. Malin; E. Shalev; D. Elsworth; D. Hidayat; B. Voight; S. R. Young; P. N. Dunkley; R. Herd; G. Norton

2003-01-01

331

Creating Griffith Observatory  

NASA Astrophysics Data System (ADS)

Griffith Observatory has been the iconic symbol of the sky for southern California since it began its public mission on May 15, 1935. While the Observatory is widely known as being the gift of Col. Griffith J. Griffith (1850-1919), the story of how Griffith’s gift became reality involves many of the people better known for other contributions that made Los Angeles area an important center of astrophysics in the 20th century. Griffith began drawing up his plans for an observatory and science museum for the people of Los Angeles after looking at Saturn through the newly completed 60-inch reflector on Mt. Wilson. He realized the social impact that viewing the heavens could have if made freely available, and discussing the idea of a public observatory with Mt. Wilson Observatory’s founder, George Ellery Hale, and Director, Walter Adams. This resulted, in 1916, in a will specifying many of the features of Griffith Observatory, and establishing a committee managed trust fund to build it. Astronomy popularizer Mars Baumgardt convinced the committee at the Zeiss Planetarium projector would be appropriate for Griffith’s project after the planetarium was introduced in Germany in 1923. In 1930, the trust committee judged funds to be sufficient to start work on creating Griffith Observatory, and letters from the Committee requesting help in realizing the project were sent to Hale, Adams, Robert Millikan, and other area experts then engaged in creating the 200-inch telescope eventually destined for Palomar Mountain. A Scientific Advisory Committee, headed by Millikan, recommended that Caltech Physicist Edward Kurth be put in charge of building and exhibit design. Kurth, in turn, sought help from artist Russell Porter. The architecture firm of John C. Austin and Fredrick Ashley was selected to design the project, and they adopted the designs of Porter and Kurth. Philip Fox of the Adler Planetarium was enlisted to manage the completion of the Observatory and become its temporary Director.

Cook, Anthony

2013-01-01

332

Northern Alaska Hydrocarbon Resources.  

National Technical Information Service (NTIS)

This report on Northern Alaska hydrocarbon resources brings together the private, federal, and state oil and gas initiatives in Northern Alaska over the past 35 years. It treats Northern Alaska oil and gas provinces as a planning unit, rather than using t...

J. D. Kreitner

1978-01-01

333

Alaska Natives & the Land.  

ERIC Educational Resources Information Center

|Pursuant to the Native land claims within Alaska, this compilation of background data and interpretive materials relevant to a fair resolution of the Alaska Native problem seeks to record data and information on the Native peoples; the land and resources of Alaska and their uses by the people in the past and present; land ownership; and future…

Arnold, Robert D.; And Others

334

North Pole Environmental Observatory  

NSDL National Science Digital Library

The North Pole Environmental Observatory (NPEO) is a collection of the University of Washington's year-round un-manned scientific platforms in the Central Basin of the Arctic Ocean. Researchers will find images, data, and other information about the three types of measurement systems: Drifting Buoys, Oceanographic Mooring, and Aerial Surveys of Hydrographic Casts. Viewers can find links to the weather and other atmospheric conditions at the observatory. The site also provides links to news coverage pertaining to NPEO. Students can study the circulation patterns of the Freshwater Switchyard of the Arctic Ocean. Everyone can learn about the international research team's yearly expeditions to the observatory.

335

SDO in Pulkovo Observatory  

NASA Astrophysics Data System (ADS)

We discuss the effective applications of the data obtained with Solar Dynamics Observatory from both instruments: The Helioseismic Magnetic Imager (HMI) and The Atmospheric Imaging Assembly (AIA). The purpose of this presentation is to show the most important problems of solar activity which are the main subjects in the Pulkovo Observatory. There with uniform data sets of magnetic fields and coronal emission in Extreme Ultraviolet bands are needed. Thus, we are planning to create SDO center in the Pulkovo Observatory, which will helps us in collaboration with existed SDO centers and provides more convenient data downloading for solar physics.

Benevolenskaya, E. E.; Efremov, V.; Ivanov, V.; Makarenko, N.; Miletsky, E.; Okunev, O.; Nagovitsin, Y.; Parfinenko, L.; Soloviev, A.; Stepanov, A.; Tlatov, A.

2010-12-01

336

Tech trek: Viewing volcanoes  

NSDL National Science Digital Library

Help students make real-world connections to Earth science concepts such as volcanoes with the help of modern technology. This article enumerates several websites where students can explore these forces of nature in a variety of ways - all from a safe distance!

Christmann, Edwin P.; Wighting, Mervyn J.; Lucking, Robert A.

2005-03-01

337

Geology of Kilauea volcano  

SciTech Connect

This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower east rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailed geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. 71 refs., 2 figs.

Moore, R.B. (Geological Survey, Denver, CO (United States). Federal Center); Trusdell, F.A. (Geological Survey, Hawaii National Park, HI (United States). Hawaiian Volcano Observatory)

1993-08-01

338

Ash from Popocatepetl Volcano  

NASA Video Gallery

The GOES-13 satellite captured this animation of an ash cloud streaming from Mexico's Popocatepetl Volcano and blowing over the town of Puebla, located to the east. This four second black and white movie was captured over several hours during the morning of April 18, 2012. > Related story > Download video

Robert Garner

2012-04-20

339

Chilean Volcano Eruption  

NASA Video Gallery

This animation includes visible and infrared imagery from GOES-13 that runs from June 4, 2011, at 1:45 p.m. EDT to June 6, 2011, at 10:45 a.m. EDT and shows the ash plume from the Puyehue-Cordón Caulle volcano in Chile (lower left) follow the wind shift from southeast to north. (no audio)

Robert Garner

2011-06-09

340

Sea floor magnetic observatory  

Microsoft Academic Search

The electromagnetic precursors of seismic hazards are widely accepted as strong evidence of the approaching earthquake or volcano eruption. The monitoring of these precursors are of main interest in densely populated areas, what creates serious problems to extract them at the strong industrial noise background. An interesting possibility to improve signal-to-noise ratio gives the installation of the observation points in

V. Korepanov; A. Prystai; F. Vallianatos; J. Makris

2003-01-01

341

The Oceanic Microbial Observatory  

NSDL National Science Digital Library

The Oceanic Microbial Observatory is a project run jointly by Dr. Craig Carlson of the University of California-Santa Barbara, and Dr. Stephen Giovannoni of Oregon State University. Centered on the Bermuda Atlantic Time-series Study site, the "goal of this microbial observatory project is to understand the cell biology and biogeochemical activities of the major bacterioplankton groups-SAR11, SAR86, SAR202 and SAR116, marine actinobacteria, SAR324, and SAR406, by applying new high throughput technologies for cell culturing, and studying the metabolism of these organisms in nature and their interactions with organic matter in the oceans." The Microbial Observatory website contains links to downloadable publications, public data sets, and poster presentations. The site also offers links to a number of other microbial observatories; and connects to the Bermuda Biological Station for Research as well.

342

A Gazebo Observatory  

NASA Astrophysics Data System (ADS)

Building an observatory in a suburban housing development can meet resistance. The city and the neighborhood can restrict design and use. The solution is a backyard gazebo for leisure sitting, meals, and observing.

Waffen, Gus

1992-06-01

343

The Pierre Auger Observatory  

SciTech Connect

The Pierre Auger Observatory is an international collaboration for the detailed study of the highest energy cosmic rays. It will operate at two similar sites, one in the northern hemisphere and one in the southern hemisphere. The Observatory is designed to collect a statistically significant data set of events with energies greater than 10{sup 19} eV and with equal exposures for the northern and southern skies.

Hojvat, C.

1997-03-01

344

Advancing the Gemini Observatory  

NASA Astrophysics Data System (ADS)

Gemini Science and User Meeting; San Francisco, California, 17-20 July 2012 More than 100 astronomers gathered in San Francisco to discuss results from the Gemini Observatory and to plan for its future. The Gemini Observatory consists of twin 8.1 meter diameter optical/infrared telescopes located on mountaintops in Hawai'i and Chile. Gemini was built and is operated by an international partnership that currently includes the United States, the United Kingdom, Canada, Chile, Australia, Brazil, and Argentina.

Hammel, Heidi B.; Levenson, Nancy A.

2012-11-01

345

Collaborative Monitoring and Hazard Mitigation at Fuego Volcano, Guatemala  

NASA Astrophysics Data System (ADS)

A portable, digital sensor network has been installed to closely monitor changing activity at Fuego volcano, which takes advantage of an international collaborative effort among Guatemala, U.S. and Canadian universities, and the Peace Corps. The goal of this effort is to improve the understanding shallow internal processes, and consequently to more effectively mitigate volcanic hazards. Fuego volcano has had more than 60 historical eruptions and nearly-continuous activity make it an ideal laboratory to study volcanic processes. Close monitoring is needed to identify base-line activity, and rapidly identify and disseminate changes in the activity which might threaten nearby communities. The sensor network is comprised of a miniature DOAS ultraviolet spectrometer fitted with a system for automated plume scans, a digital video camera, and two seismo-acoustic stations and portable dataloggers. These sensors are on loan from scientists who visited Fuego during short field seasons and donated use of their sensors to a resident Peace Corps Masters International student from Michigan Technological University for extended data collection. The sensor network is based around the local volcano observatory maintained by Instituto National de Sismologia, Vulcanologia, Metrologia e Hidrologia (INSIVUMEH). INSIVUMEH provides local support and historical knowledge of Fuego activity as well as a secure location for storage of scientific equipment, data processing, and charging of the batteries that power the sensors. The complete sensor network came online in mid-February 2007 and here we present preliminary results from concurrent gas, seismic, and acoustic monitoring of activity from Fuego volcano.

Lyons, J. J.; Bluth, G. J.; Rose, W. I.; Patrick, M.; Johnson, J. B.; Stix, J.

2007-05-01

346

Interferometric Synthetic Aperture Radar Studies of Alaska Volcanoes  

Microsoft Academic Search

position and attitude of satellites is required to remove the effect caused by the differences in the satellite orbits of the two passes. The topographic effects in the interferogram can be removed by producing a synthetic interferogram based on an accurate digital elevation model (DEM) and subtracting it from the interferogram to be studied (2,3). This results in a deformation

Zhong Lu; Charles Wicks; John Power; Daniel Dzurisin; Wayne Thatcher; Timothy Masterlark; Cascades USGS

2009-01-01

347

Studies of HF-induced Strong Plasma Turbulence at the HAARP Ionospheric Observatory  

Microsoft Academic Search

High power HF transmitters may induce a number of plasma instabilities in the interaction region of overdense ionospheric plasma. We report results from our recent experiments using over one gigawatt of HF power (ERP) to generate and study strong Langmuir turbulence (SLT) and particle acceleration at the HAARP Observatory, Gakona, Alaska. Among the effects observed and studied in UHF radar

J. P. Sheerin; N. Adham; R. G. E. Roe; M. R. Keith; B. J. Watkins; W. A. Bristow; P. A. Bernhardt; C. A. Selcher

2010-01-01

348

Tectonic Plates, Earthquakes, and Volcanoes  

NSDL National Science Digital Library

According to theory of plate tectonics, Earth is an active planet -- its surface is composed of many individual plates that move and interact, constantly changing and reshaping Earth's outer layer. Volcanoes and earthquakes both result from the movement of tectonic plates. This interactive feature shows the relationship between earthquakes and volcanoes and the boundaries of tectonic plates. By clicking on a map, viewers can superimpose the locations of plate boundaries, volcanoes and earthquakes.

2011-05-12

349

Volcanoes, Third Edition  

NASA Astrophysics Data System (ADS)

It takes confidence to title a smallish book merely “Volcanoes” because of the impliction that the myriad facets of volcanism—chemistry, physics, geology, meteorology, hazard mitigation, and more—have been identified and addressed to some nontrivial level of detail. Robert and Barbara Decker have visited these different facets seamlessly in Volcanoes, Third Edition. The seamlessness comes from a broad overarching, interdisciplinary, professional understanding of volcanism combined with an exceptionally smooth translation of scientific jargon into plain language.The result is a book which will be informative to a very broad audience, from reasonably educated nongeologists (my mother loves it) to geology undergraduates through professional volcanologists. I bet that even the most senior professional volcanologists will learn at least a few things from this book and will find at least a few provocative discussions of subjects they know.

Nye, Christopher J.

350

In Brief: Underwater volcano gets real-time monitoring  

NASA Astrophysics Data System (ADS)

A real-time underwater earthquake monitoring system was installed on the top of Kick'em Jenny, an underwater volcano located off the north coast of Grenada, on 6 May. The Real Time Offshore Seismic Station (RTOSS) consists of an ocean-bottom seismometer connected by a stretchy hose to a buoy on the ocean surface. The buoy is powered by solar panels and transmits seismic data by high-frequency radio to an observatory in Sauteurs, Grenada. The RTOSS research team, led by scientists from the Woods Hole Oceanographic Institution, is coordinating with the Grenadian National Disaster Management Agency and the Seismic Unit of the University of the West Indies to incorporate the RTOSS data into existing regional monitoring. Kick'em Jenny, the only `live' submarine volcano in the West Indies, last erupted in 2001.

Zielinski, Sarah

2007-05-01

351

Everyday astronomy @ Sydney Observatory  

NASA Astrophysics Data System (ADS)

Catering to a broad range of audiences, including many non-English speaking visitors, Sydney Observatory offers everything from school programmes to public sessions, day care activities to night observing, personal interactions to web-based outreach. With a history of nearly 150 years of watching the heavens, Sydney Observatory is now engaged in sharing the wonder with everybody in traditional and innovative ways. Along with time-honoured tours of the sky through two main telescopes, as well as a small planetarium, Sydney Observatory also boasts a 3D theatre, and offers programmes 363 days a year - rain or shine, day and night. Additionally, our website neversleeps, with a blog, YouTube videos, and night sky watching podcasts. And for good measure, a sprinkling of special events such as the incomparable Festival of the Stars, for which most of northern Sydney turns out their lights. Sydney Observatory is the oldest working observatory in Australia, and we're thrilled to be looking forward to our 150th Anniversary next year in anticipation of the International Year of Astronomy immediately thereafter.

Parello, S. L.

2008-06-01

352

Gelatin Volcanoes: Student Page  

NSDL National Science Digital Library

This is the Student Page of an activity that teaches students how and why magma moves inside volcanoes by injecting colored water into a clear gelatin cast. The Student Page contains the activity preparation instructions and materials list, key words, and a photograph of the experimental setup. There is also an extension activity question that has students predict what will happen when the experiment is run using an elongated model. This activity is part of Exploring Planets in the Classroom's Volcanology section.

353

Arecibo Observatory and the National Virtual Observatory  

NASA Astrophysics Data System (ADS)

The United States Virtual Observatoryw as established in 2001 to provide worldwide access to data acquired by U.S. observatories, including Arecibo Observatory at the National Astronomy and Ionosphere Center in Puerto Rico. Arecibo's 7-element L-band Feed Array (ALFA) is being used to survey line and continuum radiation over large areas of the 21cm-wavelength sky. Two surveys were the focus of this project: the Galactic interstellar medium HI 21cm line survey (GALFA) and the Arecibo Galaxy Environment HI Survey (AGES). Both surveys are producing large volumes of data in ``cubes'' of intensity as a function of right ascension, declination, and line-of-sight doppler velocity. An essential objective of both GALFA and AGES is to make the data available over the World Wide Web. This will require a user interface that returns the appropriate cube for a given set of coordinates, or computes a new cube on the fly covering a desired coordinate range. To implement this service, computationally efficient processing and serving methods are required. This presentation will discuss the current methods used for remote data access as well as new methods that can be used to analyze data cubes online with web tools. This work has been supported by the Research Experiences for Undergraduates program of the National Science Foundation and by the National Astronomy and Ionosphere Center operated by Cornell University under Cooperative Agreement with the NSF.

Ojalvo, Isobel

2006-12-01

354

Monitoring the Dynamic Properties of an active Mud Volcano in the West Nile Delta  

NASA Astrophysics Data System (ADS)

Large numbers of submarine mud volcanoes have been discovered in many different continental margin settings often associated with hydrocarbon provinces. They are characterized by fluid formation and fluidization processes occuring at depths of several kilometers below the seafloor which drive a complex system of interacting geochemical, geological and microbial processes. As mud volcanoes are natural leakages of oil and gas reservoirs, near-surface phenomena can be used for monitoring of processes at great depth. North Alex Mud Volcano (NAMV) in the West Nile Delta, apparently rooted at depths of more than 5 kilometers is the focus of an industry-funded research project using existing and newly developed observatory technologies to better understand and quantify the internal dynamics and its long-term variability in relation to underlying gas reservoirs. As it is known that the activity of mud volcanoes varies significantly over periods of months and weeks, the assessment of the activity of NAMV focuses on proxies of fluid and gas emanations. Since the initiation of the project in 2007 NAMV has arguably become one of the best-instrumented mud volcanoes worldwide with a network of observatories collecting permanent long-term records of chemical fluxes, seismicity, temperature, ground deformation, and methane concentration. We will report on the first results of CAT meter deployments to determine chemical fluxes and relate them to long-term records of temperature, deformation as evident from tiltmeter deployments, and seismicity from a local OBS network.

Brueckmann, W.; Tryon, M. D.; Bialas, J.; Feseker, T.; Lefeldt, M. R.

2009-12-01

355

The Collaborative Heliophysics Observatory  

NASA Astrophysics Data System (ADS)

The Collaborative Heliophysics Observatory (CHO) would provide a robust framework and enabling tools to fully utilize the VOs for scientific discovery and collaboration. Scientists across the realm of heliophysics would be able to create, use and share applications -- either as services using familiar tools or through intuitive workflows -- that orchestrate access to data across all virtual observatories. These applications can be shared freely knowing that proper recognition of data and processing components are acknowledged; that erroneous use of data is flagged; and that results from the analysis runs will in themselves be shared Ð all in a transparent and automatic fashion. In addition, the CHO would incorporate cross-VO models and tools to weave the various virtual observatories into a unified system. These provide starting points for interactions across the solar/heliospheric and heliospheric/magnetospheric boundaries.

Hurlburt, N.; Freeland, S.; Cheung, M.; Bose, P.

2007-12-01

356

Toward a green observatory  

NASA Astrophysics Data System (ADS)

Many of the modern observatories are located at remote sites, far from larger cities and away from infrastructure like power grids, water supplies and roads. On-site power generation in island mode is often the only choice to provide electricity to an observatory. During the 2008 petrol price rally, conventional power generation has received special attention and alternatives are being studied now in many organisations to keep energy prices at bay. This paper shall outline the power generation at the ESO VLT/VLTI observatory at Paranal as it is now and a plan for a possible way out of the dependency on fossil fuels in the near future. A discussion of several alternatives including wind energy, solar energy and heat recovery from a conventional power plant shall be analysed and compared. Finally, a project is being proposed to equip the VLT/VLTI with a modern alternative energy supply, based on a novel concept: Solar cooling.

Weilenmann, Ueli; Ramírez, Christian; Vanderheyden, Pierre

2010-07-01

357

Direct rate measurements of eruption plumes at Augustine volcano - A problem of scaling and uncontrolled variables  

Microsoft Academic Search

The March-April 1986 eruption of Augustine Volcano in Alaska provided an opportunity to measure directly the flux of gas, aerosol, and ash particles during explosive eruption. The eruption released 1.5 x 10 to the 6th t\\/d of ash, 24,00 t\\/d of SO2, and 10,000 t\\/d of HCl on April 3 during low-level activity. Peak eruption rates achieved several times during

William I. Rose; Grant Heiken; Kenneth Wohletz; Dean Eppler; Sumner Barr; Theresa Miller; Raymond L. Chuan; Robert B. Symonds

1988-01-01

358

NASA Earth Observatory images  

NSDL National Science Digital Library

The purpose of NASA's Earth Observatory is to provide a freely-accessible publication on the Internet where the public can obtain new satellite imagery and scientific information about our home planet. The focus is on Earth's climate and environmental change. In particular, the site may be useful to public media and educators. Earth scientists and science writers from all NASA centers, as well as all agencies and universities affiliated with NASA's Earth Science Enterprise, are encouraged to submit articles and/or images for publication on the Earth Observatory.

Administration, National A.

2010-02-16

359

Arecibo Observatory for All  

NASA Astrophysics Data System (ADS)

We describe new materials available at Arecibo Observatory for visitors with visual impairments. These materials include a guide in Braille that describes the telescope, some basic terms used in radio astronomy and frequently asked questions. We have also designed a tactile model of the telescope. We are interested that blind visitors can participate of the excitement of the visit to the worlds largest radio telescope. We would like to thank the "Fundacion Comunitaria de Puerto Rico" for the scholarship that allowed GMI to work on this project. We would like to express our gratitude to the Arecibo Observatory/NAIC for their support.

Isidro, Gloria M.; Pantoja, C. A.; Bartus, P.; La Rosa, C.

2006-12-01

360

National Undergraduate Research Observatory  

NSDL National Science Digital Library

The National Undergraduate Research Observatory (NURO) at Northern Arizona University and Lowell Observatory "is a consortium of primarily undergraduate institutions which have joined together to provide hands-on training and research experiences for undergraduate students." While the Key Projects link is under construction, users can find out about past student projects at the Undergraduate Research Experiences link. Researchers and students can request observation time and find planning and observing information. The website offers an image gallery and links to the consortium's member schools.

361

The Sudbury Neutrino Observatory  

NASA Astrophysics Data System (ADS)

The Sudbury Neutrino Observatory is a second-generation water Cherenkov detector designed to determine whether the currently observed solar neutrino deficit is a result of neutrino oscillations. The detector is unique in its use of D2O as a detection medium, permitting it to make a solar model-independent test of the neutrino oscillation hypothesis by comparison of the charged- and neutral-current interaction rates. In this paper the physical properties, construction, and preliminary operation of the Sudbury Neutrino Observatory are described. Data and predicted operating parameters are provided whenever possible.

Boger, J.; Hahn, R. L.; Rowley, J. K.; Carter, A. L.; Hollebone, B.; Kessler, D.; Blevis, I.; Dalnoki-Veress, F.; DeKok, A.; Farine, J.; Grant, D. R.; Hargrove, C. K.; Laberge, G.; Levine, I.; McFarlane, K.; Mes, H.; Noble, A. T.; Novikov, V. M.; O'Neill, M.; Shatkay, M.; Shewchuk, C.; Sinclair, D.; Clifford, E. T. H.; Deal, R.; Earle, E. D.; Gaudette, E.; Milton, G.; Sur, B.; Bigu, J.; Cowan, J. H. M.; Cluff, D. L.; Hallman, E. D.; Haq, R. U.; Hewett, J.; Hykawy, J. G.; Jonkmans, G.; Michaud, R.; Roberge, A.; Roberts, J.; Saettler, E.; Schwendener, M. H.; Seifert, H.; Sweezey, D.; Tafirout, R.; Virtue, C. J.; Beck, D. N.; Chan, Y. D.; Chen, X.; Dragowsky, M. R.; Dycus, F. W.; Gonzalez, J.; Isaac, M. C. P.; Kajiyama, Y.; Koehler, G. W.; Lesko, K. T.; Moebus, M. C.; Norman, E. B.; Okada, C. E.; Poon, A. W. P.; Purgalis, P.; Schuelke, A.; Smith, A. R.; Stokstad, R. G.; Turner, S.; Zlimen, I.; Anaya, J. M.; Bowles, T. J.; Brice, S. J.; Esch, E.-I.; Fowler, M. M.; Goldschmidt, A.; Hime, A.; McGirt, A. F.; Miller, G. G.; Teasdale, W. A.; Wilhelmy, J. B.; Wouters, J. M.; Anglin, J. D.; Bercovitch, M.; Davidson, W. F.; Storey, R. S.; Biller, S.; Black, R. A.; Boardman, R. J.; Bowler, M. G.; Cameron, J.; Cleveland, B.; Ferraris, A. P.; Doucas, G.; Heron, H.; Howard, C.; Jelley, N. A.; Knox, A. B.; Lay, M.; Locke, W.; Lyon, J.; Majerus, S.; Moorhead, M.; Omori, M.; Tanner, N. W.; Taplin, R. K.; Thorman, M.; Wark, D. L.; West, N.; Barton, J. C.; Trent, P. T.; Kouzes, R.; Lowry, M. M.; Bell, A. L.; Bonvin, E.; Boulay, M.; Dayon, M.; Duncan, F.; Erhardt, L. S.; Evans, H. C.; Ewan, G. T.; Ford, R.; Hallin, A.; Hamer, A.; Hart, P. M.; Harvey, P. J.; Haslip, D.; Hearns, C. A. W.; Heaton, R.; Hepburn, J. D.; Jillings, C. J.; Korpach, E. P.; Lee, H. W.; Leslie, J. R.; Liu, M.-Q.; Mak, H. B.; McDonald, A. B.; MacArthur, J. D.; McLatchie, W.; Moffat, B. A.; Noel, S.; Radcliffe, T. J.; Robertson, B. C.; Skensved, P.; Stevenson, R. L.; Zhu, X.; Gil, S.; Heise, J.; Helmer, R. L.; Komar, R. J.; Nally, C. W.; Ng, H. S.; Waltham, C. E.; Allen, R. C.; Bühler, G.; Chen, H. H.; Aardsma, G.; Andersen, T.; Cameron, K.; Chon, M. C.; Hanson, R. H.; Jagam, P.; Karn, J.; Law, J.; Ollerhead, R. W.; Simpson, J. J.; Tagg, N.; Wang, J.-X.; Alexander, C.; Beier, E. W.; Cook, J. C.; Cowen, D. F.; Frank, E. D.; Frati, W.; Keener, P. T.; Klein, J. R.; Mayers, G.; McDonald, D. S.; Neubauer, M. S.; Newcomer, F. M.; Pearce, R. J.; de Water, R. G. V.; Berg, R. V.; Wittich, P.; Ahmad, Q. R.; Beck, J. M.; Browne, M. C.; Burritt, T. H.; Doe, P. J.; Duba, C. A.; Elliott, S. R.; Franklin, J. E.; Germani, J. V.; Green, P.; Hamian, A. A.; Heeger, K. M.; Howe, M.; Drees, R. M.; Myers, A.; Robertson, R. G. H.; Smith, M. W. E.; Steiger, T. D.; Wechel, T. V.; Wilkerson, J. F.

2000-07-01

362

The upgraded arecibo observatory.  

PubMed

Arecibo Observatory's giant spherical reflector antenna has undergone a massive upgrading over the past 3 years. The surface of the reflector has been replaced with aluminum panels to obtain an accuracy of 3.2 mm r.m.s. over the reflector surface. The superstructure has been stabilized and modified to permit operation at S-band frequencies. A high-power S-band radar transmitter has been added to the existing UHF system. These additions and improvements provide the observatory with new and promising research capabilities in the fields of radio and radar astronomy. PMID:17782009

Lalonde, L M

1974-10-18

363

Augustine Volcano: Awake again  

Microsoft Academic Search

Editor's Note: The question posed in the title of the following item, which was written on March 20, was answered in the affirmative at 12:30 A.M. (Alaska time, equal to UT-9 h) on March 27, 1986. As of March 31, the eruption had produced numerous pyroclastic flows, and the eruptive column had reached a maximum altitude of 14 km (see

Juergen Kienle

1986-01-01

364

Internet-accessible, near-real-time volcano monitoring data for geoscience education: the Volcanoes Exploration Project---Pu`u `O`o  

Microsoft Academic Search

Internet-accessible real- and near-real-time Earth science datasets are an important resource for geoscience education, but relatively few comprehensive datasets are available, and background information to aid interpretation is often lacking. In response to this need, the U.S. Geological Survey's (USGS) Hawaiian Volcano Observatory, in collaboration with the National Aeronautics and Space Administration and the University of Hawai`i, Manoa, established the

M. P. Poland; R. Teasdale; K. Kraft

2010-01-01

365

Anatomy of a basaltic volcano  

Microsoft Academic Search

Kilauea volcano, in Hawaii, may be the best understood basaltic volcano in the world. Magma rises from a depth of 80 km or more and resides temporarily in near-surface reservoirs: eruption begins when the crust above one of these reservoirs splits open in response to a pressure increase. Repeated rift-zone eruptions compress Kilauea's flanks; after decades of accumulation, the stress

Robert I. Tilling; John J. Dvorak

1993-01-01

366

The Sudbury Neutrino Observatory  

SciTech Connect

A report is given on the status of the Sudbury Neutrino Observatory, presently under construction in the Creighton nickel mine near Sudbury, Ontario in Canada. Focus is upon the technical factors involving a measurement of the charged-current and neutral-current interactions of solar neutrinos on deuterium.

Hime, A.

1996-09-01

367

Byurakan Astrophysical Observatory  

NASA Astrophysics Data System (ADS)

Located 40 km north of Yerevan in the former Soviet Republic of Armenia. Founded in 1946 through the initiative of astronomer Victor Ambartsumian, it is now the home of the Astrophysical Observatory of the Armenian Academy of Sciences. By late 1999, the only telescope still functioning was the main 2.6 m reflecting telescope....

Murdin, P.

2000-11-01

368

Mount Wilson Observatory  

NSDL National Science Digital Library

Mount Wilson Observatory Home page includes a virtual tour and educational programs such as "Telescopes In Education" (TIE) Project, which permits remote access of a 24-inch telescope to schools (K-18) and amateur groups. Also contains professional services and historical information.

369

Gamma Ray Observatory survives  

Microsoft Academic Search

Right now the budgetary position of NASA science projects for fiscal year 1982 is shaky, outside of the Space Shuttle Program. Two scientifically crucial missions being planned are the Gamma Ray Observatory (GRO) and the Venus Orbiting Imaging Radar (VOIR). President Reagan's proposed budgetary cuts have left both programs intact but delayed. For FY 1982, GRO will be able to

Peter M. Bell

1981-01-01

370

European Southern Observatory  

NSDL National Science Digital Library

The European Southern Observatory (ESO) is an intergovernmental organization comprised of 14 member countries. Its headquarters are in Germany, but they have three observatories in Chile as well. Their website is loaded with information and visitors shouldn't miss going on the "Virtual Tours", on the far right side of the homepage. The tours are of the three observatories in Chile, and offer almost 360 degree views of beautiful, yet sparse landscapes. The tour of La Silla has two particularly beautiful views, "La Silla Moonlight" and "La Silla Sunset". Visitors interested in seeing a panning of an artist's 3D rendering of the Orion Nebula must go to the "Video" link on the left hand menu on the homepage. There are over 1400 videos to choose from, so for those not into the Orion Nebula, never fear, there are plenty of other video choices. Finally, visitors must go to the "Top 100 Images" link on the right side of the homepage to see amazing and gorgeous images taken from the ESO's various observatories.

2010-07-09

371

Mount Wilson Observatory  

Microsoft Academic Search

This paper reviews the years work at Mount Wilson Observatory including Solar Research, Lunar and Planetary Investigations, Nebulae Research, Radial Velocities, Stellar Spectrophotometry, Radiometric Measures of Stellar Spectra, Spectroscopic Determinations of Absolute Magnitude and Parallax, Laboratory Investigations, Velocity of Light, Engineering and Design, as well as Stellar Spectroscopy.

George E. Hale; Walter S. Adams; Frederick H. Seares

1931-01-01

372

Arecibo Observatory for All  

ERIC Educational Resources Information Center

We describe new materials available at the Arecibo Observatory for visitors with visual impairments. These materials include a guide in Braille that describes the telescope, explains some basic terms used in radio astronomy, and lists frequently asked questions. We have also designed a tactile model of the telescope. Our interest is in enabling…

Bartus, P.; Isidro, G. M.; La Rosa, C.; Pantoja, C. A.

2007-01-01

373

Ancient Observatories: Chaco Canyon  

NSDL National Science Digital Library

This Exploratorium site offers an online "tour" of the sites and structures within Chaco Canyon, thought to have once been an ancient solar observatory. The different pages on the tour detail several of the most famous sites where significant solar alignments occur each year. A section called "seasons and solstices" provides further information.

2009-03-12

374

Strasbourg's "First" astronomical observatory  

NASA Astrophysics Data System (ADS)

The turret lantern located at the top of the Strasbourg Hospital Gate is generally considered as the first astronomical observatory of the city, but such a qualification must be treated with caution. The thesis of this paper is that the idea of a tower-observatory was brought back by a local scholar, Julius Reichelt (1637-1717), after he made a trip to Northern Europe around 1666 and saw the "Rundetårn" (Round Tower) recently completed in Copenhagen. There, however, a terrace allowed (and still allows) the full viewing of the sky, and especially of the zenith area where the atmospheric transparency is best. However, there is no such terrace in Strasbourg around the Hospital Gate lantern. Reichelt had also visited Johannes Hevelius who was then developing advanced observational astronomy in Gdansk, but nothing of the kind followed in Strasbourg. Rather, the Hospital Gate observatory was built essentially for the prestige of the city and for the notoriety of the university, and the users of this observing post did not make any significant contributions to the progress of astronomical knowledge. We conclude that the Hospital Gate observatory was only used for rudimentary viewing of bright celestial objects or phenomena relatively low on the horizon.

Heck, André

2011-08-01

375

The Kotipu Place Observatory ATP  

NASA Astrophysics Data System (ADS)

Carter Observatory's Celestron-14 APT has been redeveloped and reinstalled at the Kotipu Place Observatory. Information on this operation is presented, together with an example of data acquired by the instrument.

Hundson, G.; Hudson, R.

1994-03-01

376

The January 2006 Volcanic-Tectonic Earthquake Swarm at Mount Martin, Alaska  

USGS Publications Warehouse

On January 8, 2006, a swarm of volcanic-tectonic earthquakes began beneath Mount Martin at the southern end of the Katmai volcanic cluster. This was the first recorded swarm at Mount Martin since continuous seismic monitoring began in 1996. The number of located earthquakes increased during the next four days, reaching a peak on January 11. For the next two days, the seismic activity decreased, and on January 14, the number of events increased to twice the previous day's total. Following this increase in activity, seismicity declined, returning to background levels by the end of the month. The Alaska Volcano Observatory located 860 earthquakes near Mount Martin during January 2006. No additional signs of volcanic unrest were noted in association with this earthquake swarm. The earthquakes in the Mount Martin swarm, relocated using the double difference technique, formed an elongated cluster dipping to the southwest. Focal mechanisms beneath Mount Martin show a mix of normal, thrust, and strike-slip solutions, with normal focal mechanisms dominating. For earthquakes more than 1 km from Mount Martin, all focal mechanisms showed normal faulting. The calculated b-value for the Mount Martin swarm is 0.98 and showed no significant change before, during, or after the swarm. The triggering mechanism for the Mount Martin swarm is unknown. The time-history of earthquake occurrence is indicative of a volcanic cause; however, there were no low-frequency events or observations, such as increased steaming associated with the swarm. During the swarm, there was no change in the b-value, and the distribution and type of focal mechanisms were similar to those in the period before the anomalous activity. The short duration of the swarm, the similarity in observed focal mechanisms, and the lack of additional signs of unrest suggest this swarm did not result from a large influx of magma within the shallow crust beneath Mount Martin.

Dixon, James P.; Power, John A.

2009-01-01

377

A reconnaissance of the major Holocene tephra deposits in the upper Cook Inlet region, Alaska  

USGS Publications Warehouse

The upper Cook Inlet region of southcentral Alaska would be significantly impacted by a major tephrafall, owing to a widespread population and heavily travelled transportation corridors. To evaluate the likelihood of such an occurrence, the tephra deposits of the region have been inventoried. Approximately 90 deposits of Holocene age are sufficiently thick to have been preserved for sampling; the frequency of such major tephrafalls ranges from 1 every 200 years near sources on the west side of upper Cook Inlet, to 1 every 1000 years on the more populated east side. The volcanoes located on the west side of upper Cook Inlet are, from north to south, Hayes, Spurr, Redoubt, and Iliamna. Hayes volcano produced the most extensive set of 6 to perhaps 8 tephra layers in the region about 3650 yr B.P. and produced one other, less extensive tephra layer during Holocene time. Spurr and Redoubt volcanoes have produced, respectively, approximately 35 and 30 Holocene layers which were dispersed eastward toward population centers. No Holocene tephra layers of Iliamna have been recognized with certainty; consequently, several tephra layers which originated to the south of the region must have a source at Augustine Volcano, or some more distant volcano. Tephra layers of Hayes volcano are calc-alkaline dacites. Most of the Spurr deposits are tholeiitic, basaltic andesites whereas those of Redoubt Volcano are calc-alkaline andesites and dacites. ?? 1985.

Riehle, J. R.

1985-01-01

378

Volcano Homework Assignment  

NSDL National Science Digital Library

In this and similar assignments students have to download quantitative natural hazard data from the Internet, load it into a spreadsheet, rank order the data, calculate recurrence times and plot the result on a log-log graph. They then interpret this graph in terms of the recurrence time of hazard events of different sizes. In many cases this includes comparing results from two different features (volcanoes, faults, rivers, etc.) Uses online and/or real-time data Addresses student fear of quantitative aspect and/or inadequate quantitative skills Uses geophysics to solve problems in other fields Addresses student misconceptions

Jaume, Steven

379

Ruiz Volcano: Preliminary report  

NASA Astrophysics Data System (ADS)

Ruiz Volcano, Colombia (4.88°N, 75.32°W). All times are local (= GMT -5 hours).An explosive eruption on November 13, 1985, melted ice and snow in the summit area, generating lahars that flowed tens of kilometers down flank river valleys, killing more than 20,000 people. This is history's fourth largest single-eruption death toll, behind only Tambora in 1815 (92,000), Krakatau in 1883 (36,000), and Mount Pelée in May 1902 (28,000). The following briefly summarizes the very preliminary and inevitably conflicting information that had been received by press time.

380

Gelatin Volcanoes: Teacher Page  

NSDL National Science Digital Library

This is the Teacher Page of an activity that teaches students how and why magma moves inside volcanoes by injecting colored water into a clear gelatin cast. Activity preparation instructions are on the Student Page, while the Teacher Page has background, preparation, and in-class information. An extension activity has the students repeat the experiment using a square bread pan to simulate the original research that was done using elongate models with triangular cross-sections. This activity is part of Exploring Planets in the Classroom's Volcanology section.

381

Lunar astronomical observatories - Design studies  

Microsoft Academic Search

The best location in the inner solar system for the grand observatories of the 21st century may be the moon. A multidisciplinary team including university students and faculty in engineering, astronomy, physics, and geology, and engineers from industry is investigating the moon as a site for astronomical observatories and is doing conceptual and preliminary designs for these future observatories. Studies

Stewart W. Johnson; Jack O. Burns; Koon Meng Chua; Nebojsa Duric; Walter H. Gerstle

1990-01-01

382

The Alaska Quaternary Center  

NSDL National Science Digital Library

This website illustrates the Alaska Quaternary Center's (at the University of Alaska, Fairbanks) commitment "to the promotion of interdisciplinary research and the enhancement of interdisciplinary instruction in Quaternary sciences." Users can view images of the field work and learn how to obtain quaternary data from the AQC Quaternary Research Geodatabase.

1969-12-31

383

The January 2005 eruption of Bezymianny Volcano, Russia: Comparing ground and airborne thermal camera images to rapid-response ASTER satellite data  

NASA Astrophysics Data System (ADS)

Based on seismic observations, a large explosion occurred at the summit of Bezymianny Volcano, Kamchatka Peninsula, Russia on 11 January 2005. This prompted the acquisition of fifteen (four day and eleven night) Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite images of the area over the next eight months. These data provided an unprecedented time series of high-resolution thermal infrared (TIR) data of the volcano and its deposits, as an initial test of the new ASTER rapid-response program (in conjunction with the Alaska Volcano Observatory). A field campaign was undertaken in August 2005 to monitor and interpret recent activity using both ground and airborne Forward Looking Infrared Radiometers (FLIR) surveys. Airborne visual and FLIR observations revealed that the morphology of the summit lava dome had changed significantly since August 2004. The dome currently contains a collapse crater roughly 200 m in diameter and a small viscous lava lobe that drapes the crater rim. Stepped scarps within the new summit crater suggest a partial collapse mechanism of formation rather than a purely explosion-related origin. Activity in 2005 also created a v-shaped notch in the southern part of the dome, which had observable high temperature fumarolic activity and may be an area of future structural weakness. The January explosion produced a plan-view mushroom shaped deposit branching from the summit that pooled against the 1956 crater wall, with some material travelling up to 3 km to the southeast away from the horseshoe-shaped crater. The FLIR acquisitions detected temperatures above 120° C within these summit deposits, particularly within oval-shaped collapse pits, likely created from deposition of the hot material onto snow and ice. The slow cooling rate is most likely a function of the deposit thickness by the crater rim and the thermal insulation of the surrounding rocks. Observed ASTER thermal anomalies in combination with FLIR and standard photography suggest the events beginning 11 January resulted in the formation of a summit collapse crater, a small viscous lava flow, and a dense block and ash flow that moved initially to the northwest, and then spread out, following the lowest elevation areas within the crater rim. The sequence of these events is still under study using scientific observations made from FLIR and ASTER data.

Carter, A. J.; Ramsey, M. S.; Belousov, A.; Wessels, R.; Dehn, J.

2005-12-01

384

The CALIPSO Borehole Project at Soufrière Hills Volcano, Montserrat, BWI: Status and Scientific Overview of Prodigious Dome Collapse of July 2003  

Microsoft Academic Search

The CALIPSO Project (Caribbean Andesite Lava Island-volcano Precision Seismo-geodetic Observatory) has greatly enhanced the monitoring and scientific infrastructure at the Soufrière Hills Volcano, Montserrat with the recent installation of an integrated array of borehole and surface geophysical instrumentation at four sites (Mattioli et al., 2004). The sensor package at each site includes: a single-component, very broad band, Sacks-Evertson strainmeter, a

G. S. Mattioli; B. Voight; A. T. Linde; I. S. Sacks; P. Watts; D. Hidayat; S. R. Young; C. Widiwijayanti; E. Shalev; P. E. Malin; D. Elsworth; P. Williams; E. van Boskirk; G. Thompson; T. Syers; R. S. Sparks; B. Schleigh; G. Norton; J. Neuberg; V. Miller; N. McWhorter; W. Johnston; P. Dunkley; A. B. Clarke; V. Bass

2005-01-01

385

Report on Geomagnetic Observatory Operations, 1990.  

National Technical Information Service (NTIS)

Contents: A Report On Geomagnetic Observatory Operations, 1990; Tables--Geomagnetic Observatories in Operation During 1990, Annual Means Available (as of April 1990), Notes on Observatories (as of April 1990), Digital Geomagnetic Observatories, 1990; MAPS...

K. L. Svendsen W. M. Davis S. J. McLean H. Meyers

1992-01-01

386

1986 eruption of Augustine Volcano: Public safety response by Alaskan volcanologists  

NASA Astrophysics Data System (ADS)

Although, in a general sense, all scientific work on hazardous natural phenomena such as weather, earthquakes, and volcanic eruptions can advance the public safely, we wish to describe some specific actions that were motivated by direct considerations of safety. These kinds of actions are normally at the fringes of scientific research and become important only during some crisis; in this instance, the crisis was the eruption on March 27, 1986, of Augustine Volcano (Figure 1). The agencies involved were the Geophysical Institute of the University of Alaska (UAGI), the Division of Geological and Geophysical Surveys of the State of Alaska (DGGS), and the Alaska Branch of the United States Geological Survey (USGS). The central theme of our mutual effort during the crisis was to communicate to response agencies and the public, in the most meaningful way possible, a prediction of what could happen next and how it would affect the public.

Kienle, J.; Davies, J. N.; Miller, T. P.; Yount, M. E.

387

Alaska SeaLife Center  

NSDL National Science Digital Library

Located in Seward, Alaska, the Alaska SeaLife Center is a non-profit marine science facility dedicated to understanding and maintaining the integrity of the marine ecosystem of Alaska through research, rehabilitation and public education. The Center's research and rehabilitation facilities and naturalistic exhibits immerse visitors in the dynamic marine ecosystems of Alaska. Includes links to additional resources for students and teachers.

388

Energy and the states: Alaska  

Microsoft Academic Search

In Alaska, energy policy simply means oil and gas. The state gets 85% of its revenue from oil and gas, and the nation gets about 25% of its domestic oil production from Alaska. Therefore, oil and gas production is important to Alaska, and the state's energy policies reflect this fact. Three separate policy initiatives comprise the strategy for realizing Alaska's

Eason

2009-01-01

389

Volcano spacing and plate rigidity  

SciTech Connect

In-plane stresses, which accompany the flexural deformation of the lithosphere under the load adjacent volcanoes, may govern the spacing of volcanoes in hotspot provinces. Specifically, compressive stresses in the vicinity of a volcano prevent new upwelling in this area, forcing a new volcano to develop at a minimum distance that is equal to the distance in which the radial stresses change from compressional to tensile (the inflection point). If a volcano is modeled as a point load on a thin elastic plate, then the distance to the inflection point is proportional to the thickness of the plate to the power of 3/4. Compilation of volcano spacing in seven volcanic groups in East Africa and seven volcanic groups of oceanic hotspots shows significant correlation with the elastic thickness of the plate and matches the calculated distance to the inflection point. In contrast, volcano spacing in island arcs and over subduction zones is fairly uniform and is much larger than predicted by the distance to the inflection point, reflecting differences in the geometry of the source and the upwelling areas.

Brink, U. (Stanford Univ., California (USA))

1991-04-01

390

The STEREO Observatory  

NASA Astrophysics Data System (ADS)

The Solar Terrestrial Relations Observatory (STEREO) is the third mission in NASA’s Solar Terrestrial Probes program. The mission is managed by the Goddard Space Flight Center (GSFC) and implemented by The Johns Hopkins University Applied Physics Laboratory (JHU/APL). This two-year mission provides a unique and revolutionary view of the Sun Earth system. Consisting of two nearly identical observatories, one ahead of Earth in its orbit around the Sun and the other trailing behind the Earth, the spacecraft trace the flow of energy and matter from the Sun to Earth and reveal the three-dimensional structure of coronal mass ejections (CMEs) to help explain their genesis and propagation. From its unique side-viewing vantage point, STEREO also provides alerts for Earth-directed solar ejections. These alerts are broadcast at all times and received either by NASA’s Deep Space Network (DSN) or by various space-weather partners.

Driesman, Andrew; Hynes, Shane; Cancro, George

2008-04-01

391

The Ultimate Private Observatory  

NASA Astrophysics Data System (ADS)

An amateur astronomer from Washington Parish, Southeast Louisiana, USA has designed and built an amazing observatory. It is not only an astronomical observatory, but a home theater, and tornado shelter designed to take a direct hit from an F5 tornado. The facility is fully equipped and automated, with a hydraulically driven roof that weighs 20,571 lbs., which lifts up, then rolls away to the end of the tracks. This leaves the user sitting inside of four 14-foot high walls open to the night sky. It has two premium quality telescopes for viewing deep space and objects inside the solar system. The chair that the observer sits on is also hydraulically driven.

Aymond, J.

2009-03-01

392

The Distribution and Movement of Volcanic Ash and SO2 Observed in Satellite Data from the Eruption of Augustine Volcano, 2006  

Microsoft Academic Search

Mt. Augustine is an island volcano located in Cook Inlet 275 km SSW of Anchorage, Alaska, that erupted explosively on 11, 13, 14, 17, and 27-30 January 2006. Visible and infrared wavelength satellite data detected and tracked the movements of plumes and volcanic clouds, including ash and SO2. Transport of these volcanic clouds was predicted using the Puff dispersion model.

K. G. Dean; J. Dehn; K. L. Wallace; F. Prata; C. F. Cahill

2006-01-01

393

Arecibo Observatory for All  

NASA Astrophysics Data System (ADS)

We describe new materials available at the Arecibo Observatory for visitors with visual impairments. These materials include a guide in Braille that describes the telescope, explains some basic terms used in radio astronomy, and lists frequently asked questions. We have also designed a tactile model of the telescope. Our interest is in enabling blind visitors to participate in the excitement of visiting the world's largest radio telescope.

Bartus, P.; Isidro, G. M.; La Rosa, C.; Pantoja, C. A.

394

National Radio Observatory  

NSDL National Science Digital Library

The National Radio Astronomy Observatory (NRAO) "operates powerful, advanced radio telescopes spanning the western hemisphere." The website is nicely divided into information for the general public, astronomers, and teachers and students. Users can learn all about NRAO's many telescopes located throughout the United States. Researchers can find out about meetings, conferences, software resources, and surveys. Amateur radio astronomers can find links describing how to build antennas and interferometers. Everyone will enjoy the numerous images of astronomical phenomena and NRAO's telescopes and facilities.

395

Salt Plains Microbial Observatory  

NSDL National Science Digital Library

This site is home of the Salt Plains Microbial Observatory, located in the Salt Plains National Wildlife Refuge in northern Oklahoma. This area has permitted the first extensive study of a non-marine, terrestrial, hypersaline environment. The web site offers information about the extreme environment, images and video clips of its microbial inhabitants, an image-rich summary of research activities, information about summer courses and research opportunities, a list of publications, and links to other informative resources pertaining to hypersaline environments.

Buchheim, Mark; University Of Tulsa, Biological S.

396

Dominion Radio Astrophysical Observatory  

NASA Astrophysics Data System (ADS)

The Dominion Radio Astrophysical Observatory began operating in 1959, and joined the NATIONAL RESEARCH COUNCIL in 1970. It became part of the Herzberg Institute of Astrophysics in 1975. The site near Penticton, BC has a 26 m radio telescope, a seven-antenna synthesis telescope on a 600 m baseline and two telescopes dedicated to monitoring the solar radio flux at 10.7 cm. This part of the Institu...

Murdin, P.

2000-11-01

397

Mount Wilson Observatory  

Microsoft Academic Search

Mount Wilson Observatory, located in the San Gabriel Mountains near Pasadena, California, was founded in 1904 by George Ellery Hale with financial support from Andrew Carnegie. In the 1920s and 1930s, working at the 2.5 m Hooker telescope, Edwin Hubble made two of the most important discoveries in the history of astronomy: first, that `nebulae' are actually island universes---galaxies---each with

P. Murdin

2000-01-01

398

Warner and Swasey Observatory  

NASA Astrophysics Data System (ADS)

Located at Washburn University in Topeka, Kansas, home of the Warner & Swasey 29 cm refractor. Built in the late 1800s, the telescope was displayed at the 1912 World's Fair, then acquired by Washburn College. Crane Observatory was built on campus to house the telescope. The Warner & Swasey survived a tornado in the 1960s. During telescope refurbishment, which was completed in 1998, all of the ori...

Murdin, P.

2000-11-01

399

The Green Bank Observatory  

NASA Astrophysics Data System (ADS)

The National Radio Astronomy Observatory is located in the small town of Green Bank in eastern West Virginia. The site is the home to many historical artifacts and is itself a part of the culture of radio astronomy as well as a significant player in current radio astronomy research. Photographs of the site will supplement a verbal description of the on-site activities and tools.

Sullivan, James

2000-05-01

400

Megalithic observatory Kokino  

NASA Astrophysics Data System (ADS)

In 2001, on the footpath of a mountain peak, near the village of Kokino, archeologist Jovica Stankovski discovered an archeological site from The Bronze Age. The site occupies a large area and is scaled in two levels. Several stone seats (thrones) are dominant in this site and they are pointing towards the east horizon. The high concentration of the movable archeological material found on the upper platform probably indicates its use in a function containing still unknown cult activities. Due to precise measurements and a detailed archaeoastronomical analysis of the site performed in the past three years by Gjore Cenev, physicist from the Planetarium in Skopje, it was shown that the site has characteristics of a sacred site, but also of a Megalithic Observatory. The markers found in this observatory point on the summer and winter solstices and spring and autumn equinoxes. It can be seen that on both sides of the solstice markers, that there are markers for establishing Moon's positions. The markers are crafted in such a way that for example on days when special rites were performed (harvest rites for example) the Sun filled a narrow space of the marker and special ray lighted the man sitting on only one of the thrones, which of course had a special meaning. According to the positions of the markers that are used for Sun marking, especially on the solstice days, it was calculated that this observatory dates from 1800 B.C.

Cenev, Gj.

2006-05-01

401

The Russian Virtual Observatory  

NASA Astrophysics Data System (ADS)

The Russian Virtual Observatory (RVO) will be an integral component of the International Virtual Observatory (IVO). The RVO has the main goal of integrating resources of astronomical data accumulated in Russian observatories and institutions (databases, archives, digitized glass libraries, bibliographic data, a remote access system to information and technical resources of telescopes etc.), and providing transparent access for scientific and educational purposes to the distributed information and data services that comprise its content. Another goal of the RVO is to provide Russian astronomers with on-line access to the rich volumes of data and metadata that have been, and will continue to be, produced by astronomical survey projects. Centre for Astronomical Data (CAD), among other Russian institutions, has had the greatest experience in collecting and distributing astronomical data for more than 20 years. Some hundreds of catalogs and journal tables are currently available from the CAD repository. More recently, mirrors of main astronomical data resources (VizieR, ADS, etc) are now maintained in CAD. Besides, CAD accumulates and makes available for the astronomical community information on principal Russian astronomical resources.

Dluzhnevskaya, O. B.; Malkov, O. Yu.; Kilpio, A. A.; Kilpio, E. Yu.; Kovaleva, D. A.; Sat, L. A.

402

Building International Space Observatories  

NASA Astrophysics Data System (ADS)

In this brief presentation I will focus on international collaborations for building x-ray observatories. Two primary approaches seem relevant for discussion: 1. Contribution of an instrument by one Agency to a mission led by another 2. Substantial participation by 2 or more Agencies in designing and building an Observatory - close to equal partnerships. Most of our experience in x-ray astronomy falls into the first category, and I will illustrate by briefly summarizing Chandra. The second case will be assessed by reviewing the community's and Agencies' efforts on the International X-ray Observatory (IXO). What can we distill from the successes and difficulties encountered over the past several years? Thoughts about how we might proceed in the future will be shared during the subsequent Panel Discussion. Independent of the development approach, we seem to have general agreement that the bulk of the observing time should be open to scientists world-wide through Peer Review to optimize the science return.

Tananbaum, Harvey

2013-04-01

403

Groundwater at Mayon, Volcano  

NASA Astrophysics Data System (ADS)

Around Mayon Volcano, Philippines, anecdotal evidence and rainfall normalized spring discharge data suggest that the water table 8 km from the summit of the volcano drops prior to eruptions. Residents report that they had to deepen their shallow wells in 1993 (some before and others following the eruption). In some cases they had to dig as far as 5 meters deeper to reach the water table. Significant decreases in spring discharge were recorded prior to the 1999 phreatic explosions and explosive eruption in 2000. A lesser decrease in spring discharge was recorded prior to the 2001 explosive eruptions. The cause of the observed correlation is not yet understood. Mechanisms consider include decrease in rainfall and boiling away of groundwater due to magmatic intrusion. Dilatation of the volcano may cause an increase in pore pressure, opening of cracks, and inflation of the ground surface that would all result in lower water table levels and decreases in spring discharges. Lack of significant hydraulic precursors prior to the 2001 eruptions may be due to a sustained state of inflation following the eruption of 2000. To better understand the relationship between changes in the volcanic system and changes in the groundwater system surrounding Mayon, instruments were installed about eight kilometers from the summit immediately following the explosive eruption of 26 July 2001. Parameters monitored include rainfall data, water levels in four shallow wells, discharge in the main river basin, and spring discharge. The aquifers at eight kilometers are predominantly poorly sorted lahar flow deposits. Characterization of these highly permeable aquifers has been conducted. Preliminary data include porosity ranges, hydraulic conductivity estimates, and response to rainfall. Water samples have been collected that are intended for geo-chemical analysis to determine if the water is predominantly meteoric or magmatic in origin. Numerical modeling of the system using the above mentioned parameters is planned. We expect to determine what the magnitude of strain produced by the intruding magma would have to be for the lowering of the water table that was observed in 1993, 1999, and 2000. This strain will then be compared with the expected strain from volcanic intrusion to determine if strain alone could be responsible for the changes to the groundwater system.

Albano, S. E.; Sandoval, T.; Toledo, R.

2001-12-01

404

Galactic Super-volcano in Action  

NASA Astrophysics Data System (ADS)

A galactic "super-volcano" in the massive galaxy M87 is erupting and blasting gas outwards, as witnessed by NASA's Chandra X-ray Observatory and NSF's Very Large Array. The cosmic volcano is being driven by a giant black hole in the galaxy's center and preventing hundreds of millions of new stars from forming. Astronomers studying this black hole and its effects have been struck by the remarkable similarities between it and a volcano in Iceland that made headlines earlier this year. At a distance of about 50 million light years, M87 is relatively close to Earth and lies at the center of the Virgo cluster, which contains thousands of galaxies. M87's location, coupled with long observations over Chandra's lifetime, has made it an excellent subject for investigations of how a massive black hole impacts its environment. "Our results show in great detail that supermassive black holes have a surprisingly good control over the evolution of the galaxies in which they live," said Norbert Werner of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University and the SLAC National Accelerator Laboratory, who led one of two papers describing the study. "And it doesn't stop there. The black hole's reach extends ever farther into the entire cluster, similar to how one small volcano can affect practically an entire hemisphere on Earth." The cluster surrounding M87 is filled with hot gas glowing in X-ray light, which is detected by Chandra. As this gas cools, it can fall toward the galaxy's center where it should continue to cool even faster and form new stars. However, radio observations with the Very Large Array suggest that in M87 jets of very energetic particles produced by the black hole interrupt this process. These jets lift up the relatively cool gas near the center of the galaxy and produce shock waves in the galaxy's atmosphere because of their supersonic speed. The scientists involved in this research have found the interaction of this cosmic "eruption" with the galaxy's environment to be very similar to that of the Eyjafjallajokull volcano, which forced much of Europe to close its airports earlier this year. With Eyjafjallajokull, pockets of hot gas blasted through the surface of the lava, generating shock waves that can be seen passing through the grey smoke of the volcano. The hot gas then rises up in the atmosphere, dragging the dark ash with it. This process can be seen in a movie of the Eyjafjallajokull volcano where the shock waves propagating in the smoke are followed by the rise of dark ash clouds into the atmosphere. In the analogy with Eyjafjallajokull, the energetic particles produced in the vicinity of the black hole rise through the X-ray emitting atmosphere of the cluster, lifting up the coolest gas near the center of M87 in their wake, much like the hot volcanic gases drag up the clouds of dark ash. And just like the volcano here on Earth, shockwaves can be seen when the black hole pumps energetic particles into the cluster gas. "This analogy shows that even though astronomical phenomena can occur in exotic settings and over vast scales, the physics can be very similar to events on Earth," said co-author Aurora Simionescu also of the Kavli Institute. In M87, the plumes of cooler gas being lifted upwards contain as much mass as all of the gas contained within 12,000 light years of the center of the galaxy cluster. This shows the black hole-powered volcano is very efficient at blasting the galaxy free of the gas that would otherwise cool and form stars. "This gas could have formed hundreds of millions of stars if the black hole had not removed it from the center of the galaxy. That seems like a much worse disruption than what the airline companies on Earth had to put up with earlier this year," said Evan Million, a graduate student at Stanford University and lead-author of the other paper to be published about this deep study of M87. The eruption in M87 that lifted up the cooler gas must have occurred about 150 million years earlie

2010-08-01

405

Volcanic SO2 Emissions vs. Seismicity - July 2002 LP Swarm, Soufriere Hills Volcano, Montserrat  

Microsoft Academic Search

Volcanic sulfur dioxide (SO2) measurements of passive plumes have recently improved with the application of Differential Optical Absorption Spectroscopy (DOAS). In January 2002, the Montserrat Volcano Observatory installed two fixed DOAS instruments which collect rapid, continuous measurements of SO2 emissions. For the first time, SO2 fluxes are being collected on a time scale of minutes, allowing short-term changes to be

J. Shannon; G. Bluth; M. Edmonds; G. Thompson

2003-01-01

406

Upper crustal structure of an active volcano from refraction\\/reflection tomography, Montserrat, Lesser Antilles  

Microsoft Academic Search

To better understand the volcanic phenomena acting on Montserrat, the SEA-CALIPSO seismic experiment (Seismic Experiment with Airgun-source - Caribbean Andesitic Lava Island Precision Seismo-geodetic Observatory) was conducted in 2007 December with the aim of imaging the upper crust and the magmatic system feeding the active Soufriére Hills Volcano. The 3-D survey covered an area of about 50 × 40 km

M. Paulatto; T. A. Minshull; B. Baptie; S. Dean; J. O. S. Hammond; T. Henstock; C. L. Kenedi; E. J. Kiddle; P. Malin; C. Peirce; G. Ryan; E. Shalev; R. S. J. Sparks; B. Voight

2010-01-01

407

Networking of Icelandic Earth Infrastructures - Natural laboratories and Volcano Supersites  

NASA Astrophysics Data System (ADS)

The back-bone of Icelandic geoscientific research infrastructure is the country's permanent monitoring networks, which have been built up to monitor seismic and volcanic hazard and deformation of the Earth's surface. The networks are mainly focussed around the plate boundary in Iceland, particularly the two seismic zones, where earthquakes of up to M7.3 have occurred in centuries past, and the rift zones with over 30 active volcanic systems where a large number of powerful eruptions have occurred, including highly explosive ones. The main observational systems are seismic, strong motion, GPS and bore-hole strain networks, with the addition of more recent systems like hydrological stations, permanent and portable radars, ash-particle counters and gas monitoring systems. Most of the networks are owned by a handful of Icelandic institutions, but some are operated in collaboration with international institutions and universities. The networks have been in operation for years to decades and have recorded large volumes of research quality data. The main Icelandic infrastructures will be networked in the European Plate Observing System (EPOS). The plate boundary in the South Iceland seismic zone (SISZ) with its book-shelf tectonics and repeating major earthquakes sequences of up to M7 events, has the potential to be defined a natural laboratory within EPOS. Work towards integrating multidisciplinary data and technologies from the monitoring infrastructures in the SISZ with other fault regions has started in the FP7 project NERA, under the heading of Networking of Near-Fault Observatories. The purpose is to make research-quality data from near-fault observatories available to the research community, as well as to promote transfer of knowledge and techical know-how between the different observatories of Europe, in order to create a network of fault-monitoring networks. The seismic and strong-motion systems in the SISZ are also, to some degree, being networked nationally to strengthen their early warning capabilities. In response to the far-reaching dispersion of ash from the 2010 Eyjafjallajökull eruption and subsequent disturbance to European air-space, the instrumentation of the Icelandic volcano observatory was greatly improved in number and capability to better monitor sub-surface volcanic processes as well as the air-borne products of eruptions. This infrastructure will also be networked with other European volcano observatories in EPOS. Finally the Icelandic EPOS team, together with other European collaborators, has responded to an FP7 call for the establishment of an Icelandic volcano supersite, where land- and space-based data will be made available to researchers and hazard managers, in line with the implementation plan of the GEO. The focus of the Icelandic volcano supersite are the active volcanoes in Iceland's Eastern volcanic zone.

Vogfjörd, K. S.; Sigmundsson, F.; Hjaltadóttir, S.; Björnsson, H.; Arason, Ø.; Hreinsdóttir, S.; Kjartansson, E.; Sigbjörnsson, R.; Halldórsson, B.; Valsson, G.

2012-04-01

408

VolcanoWorld Online Lessons  

NSDL National Science Digital Library

These five activities are sequential and are designed to cover introductory volcano topics. Included are objectives, materials lists, procedures, and a selection of related sites for students to access.

409

Dynamic Controls of Fluid and Gas Flow at North Alex Mud Volcano, West Nile Delta  

NASA Astrophysics Data System (ADS)

The North Alex Mud Volcano (NAMV) is located at a water depth of 500m above a large deep-seated gas reservoir on the upper slope of the western Nile deep-sea fan. It has been the object of an integrated study of fluid and gas flow using existing and newly developed observatory technologies to better constrain and quantify devolatilisation and defluidisation patterns and their long-term variability in relation to underlying hydrocarbon reservoirs. As it is known that the activity of mud volcanoes varies significantly over periods of months and weeks, the assessment of the activity of NAMV focuses on proxies of fluid and gas emanations. Submarine mud volcanoes are usually characterized by fluid formation and fluidization processes occuring at depths of several kilometers below the seafloor, driving a complex system of interacting geochemical, geological and microbial processes. Mud volcanoes are natural leakages of oil and gas reservoirs. Near-surface observations made at such sites can therefore be used to monitor phenomena that occur at greater depth. Since the initiation of the project in 2007, NAMV has arguably become one of the best-instrumented mud volcanoes worldwide with a network of observatories collecting long-term records of chemical fluxes, seismicity, temperature, ground deformation, and methane concentration. In addition five research cruises collected complementary geophysical and geological data and samples. In the summer of 2010 a large number of monitoring systems has been recovered which provide us with a synoptic view of the internal dynamics of an active mud volcano. We will present an integrated analysis based on ship-based and sea-floor observations.

Brueckmann, W.; Bialas, J.; Jegen, M. D.; Lefeldt, M. R.; Hoelz, S.; Feseker, T.

2010-12-01

410

Mud volcanoes in deepwater Nigeria  

Microsoft Academic Search

Detailed study of 3D seismic data from deepwater Nigeria has revealed the presence of features interpreted to be mud volcanoes. They occur in an upper slope environment seen as 1–2km circular features at the seabed. Seabed cores from the mud volcanoes contain oil, gas and sand\\/shale–clast content richer than the seabed background. Pliocene fossils have been identified in the cores,

K Graue

2000-01-01

411

Distributed Observatory Management  

NASA Astrophysics Data System (ADS)

A collection of tools for collaboratively managing a coastal ocean observatory have been developed and used in a multi-institutional, interdisciplinary field experiment. The Autonomous Ocean Sampling Network program created these tools to support the Adaptive Sampling and Prediction (ASAP) field experiment that occurred in Monterey Bay in the summer of 2006. ASAP involved the day-to-day participation of a large group of researchers located across North America. The goal of these investigators was to adapt an array of observational assets to optimize data collection and analysis. Achieving the goal required continual interaction, but the long duration of the observatory made sustained co-location of researchers difficult. The ASAP team needed a remote collaboration tool, the capability to add non-standard, interdisciplinary data sets to the overall data collection, and the ability to retrieve standardized data sets from the collection. Over the course of several months and "virtual experiments," the Ocean Observatory Portal (COOP) collaboration tool was created, along with tools for centralizing, cataloging, and converting data sets into common formats, and tools for generating automated plots of the common format data. Accumulating the data in a central location and converting the data to common formats allowed any team member to manipulate any data set quickly, without having to rely heavily on the expertise of data generators to read the data. The common data collection allowed for the development of a wide range of comparison plots and allowed team members to assimilate new data sources into derived outputs such as ocean models quickly. In addition to the standardized outputs, team members were able to produce their own specialized products and link to these through the collaborative portal, which made the experimental process more interdisciplinary and interactive. COOP was used to manage the ASAP vehicle program from its start in July 2006. New summaries were posted to the COOP tool on a daily basis, and updated with announcements on schedule, system status, voting results from previous day, ocean, atmosphere, hardware, adaptive sampling and coordinated control and forecast. The collection of standardized data files was used to generate daily plots of observed and predicted currents, temperature, and salinity. Team members were able to participate from any internet-accessible location using common Internet browsers, and any team member could add to the day's summary, point out trends and discuss observations, and make an adaptation proposal. If a team member submitted a proposal, team-wide discussion and voting followed. All interactions were archived and left publicly accessible so that future experiments could be made more systematic with increased automation. The need for collaboration and data handling tools is important for future ocean observatories, which will require 24-hour per day, 7-day a week interactions over many years. As demonstrated in the ASAP experiment, the COOP tool and associated data handling tools allowed scientists to coherently and collaboratively manage an ocean observatory, without being co-located at the observatory. Lessons learned from operating these collaborative tools during the ASAP experiment provide an important foundation for creating even more capable portals.

Godin, M. A.; Bellingham, J. G.

2006-12-01

412

Mahukona: The missing Hawaiian volcano  

SciTech Connect

New bathymetric and geochemical data indicate that a seamount west of the island of Hawaii, Mahukona, is a Hawaiian shield volcano. Mahukona has weakly alkalic lavas that are geochemically distinct. They have high {sup 3}He/{sup 4}He ratios (12-21 times atmosphere), and high H{sub 2}O and Cl contents, which are indicative of the early state of development of Hawaiian volcanoes. The He and Sr isotopic values for Mahukona lavas are intermediate between those for lavas from Loihi and Manuna Loa volcanoes and may be indicative of a temporal evolution of Hawaiian magmas. Mahukona volcano became extinct at about 500 ka, perhaps before reaching sea level. It fills the previously assumed gap in the parallel chains of volcanoes forming the southern segment of the Hawaiian hotspot chain. The paired sequence of volcanoes was probably caused by the bifurcation of the Hawaiian mantle plume during its ascent, creating two primary areas of melting 30 to 40 km apart that have persisted for at least the past 4 m.y.

Garcia, M.O.; Muenow, D.W. (Univ. of Hawaii, Honolulu (USA)); Kurz, M.D. (Woods Hole Oceanographic Institution, MA (USA))

1990-11-01

413

Geothermal Technologies Program: Alaska  

SciTech Connect

This fact sheets provides a summary of geothermal potential, issues, and current development in Alaska. This fact sheet was developed as part of DOE's GeoPowering the West initiative, part of the Geothermal Technologies Program.

Not Available

2005-02-01

414

Alaska Earthquake Information Center  

NSDL National Science Digital Library

Housed at the Geophysical Institute at the University of Alaska Fairbanks, the Alaska Earthquake Information Center reports and provides information on seismic activity in Alaska. While its southern Pacific coast colleague, California, gets a lot more attention when it comes to earthquakes, Alaska experienced a magnitude 6.7 earthquake already this summer and was rocked by a 7.9 in 2002. The site offers links to general information about the center, general earthquake information, research activities at the center, education and outreach materials (including information on seismology education projects), and much more. The site is well populated with materials and should provide a great resources for those interested in North American seismic events.

415

1964 Alaska Earthquake  

NSDL National Science Digital Library

This video adapted from the Valdez Museum & Historical Archive, explores what happened during the Great Alaska Earthquake of 1964 through original footage, first-person accounts, and animations illustrating plate tectonics.

Foundation, Wgbh E.

2009-02-25

416

Alaska's Mineral Industry, 1989.  

National Technical Information Service (NTIS)

Alaska's mineral industry experienced positive growth during 1989, especially in the hard-rock mining and exploration sectors, but suffered declines in mineral development expenditures, in sand-and-gravel, and in stone production. Overall value of mineral...

T. K. Bundtzen R. C. Swainbank J. R. Deagen J. L. Moore

1990-01-01

417

Alaska's Land-1974.  

National Technical Information Service (NTIS)

The 1974 annual report reviews the Commission's activities. A statewide Resources inventory of Alaska was completed and the Commission's structure was reorganized to better develop policies on anticipated land use planning issues.

1975-01-01

418

Observatory bibliographies: current practices  

NASA Astrophysics Data System (ADS)

Astronomical facilities, both large and small, space- and ground-based, independently create and maintain publication databases that can be used to characterize the scientific productivity and impact of these facilities. This paper will present the results of a new survey that reveals how individual observatories manage bibliographies as well as their motivations behind them. We will examine such factors as: criteria for paper inclusion, metadata collected, staff involved, inter-operability, and other aspects particular to bibliographies. Finally, we learn how these data are analyzed by these facilities. In sum, the survey results characterize methods and motivations currently at work in astronomical facilities.

Lagerstrom, Jill; Winkelman, Sherry; Grothkopf, Uta; Bishop, Marsha

2012-09-01

419

Observatory changes hands  

NASA Astrophysics Data System (ADS)

The Carnegie Institution of Washington (D.C.) announced on January 5 that it will transfer control of the Mount Wilson Observatory, which it has managed since 1904, to the Mount Wilson Institute, a private group established in 1986. The Mount Wilson Institute's board is made up of representatives from the Carnegie Institution, Los Angeles County Museum of Natural History, Los Angeles County Department of Parks and Recreation, U.S. Forest Service, the southern California business community, and the astronomy departments of the University of Southern California and University of California, Los Angeles.

Wainger, Lisa A.

420

Strasbourg Observatory Archives Revisited  

NASA Astrophysics Data System (ADS)

Official talks in France and Germany after World War I were generally of hatred and revenge. Strasbourg Observatory had just changed nationality (from Prussian to French) for the first time (this would happen again at the outbreak of WWII and after the conflict). Documents show that astronomers did not share the general attitude. For example the inventory book started in German was continued in French after 1918. It is moving to see those different handwritings in two different languages on the same pages -- making of that book a unique document in various respects, but also reminding us that the native language of the region was in fact Alsacian.

Heck, A.

2002-12-01

421

Water Resources of Alaska  

NSDL National Science Digital Library

The Water Resources of Alaska homepage is provided by the US Geological Survey. The goal of this project is to study and understand Alaska's hydrology (surface water, ground water, and water quality) for use and management of the nation's water resources. The site features a list of published reports and information about current projects as well as a vast amount of hydrologic data such as surface water, ground water, water quality, glaciers, water use, and hydrologic data reports.

Geological Survey (U.S.). Water Resources Division. Alaska District.

1999-01-01

422

Alaska looks HOT!  

Microsoft Academic Search

Production in Alaska has been sluggish in recent years, with activity in the Prudhoe Bay region in the North Slope on a steady decline. Alaska North Slope (ANS) production topped out in 1988 at 2.037 MMbo\\/d, with 1.6 MMbo\\/d from Prudhoe Bay. This year operators expect to produce 788 Mbo\\/d from Prudhoe Bay, falling to 739 Mbo\\/d next year. ANS

Belcher

1997-01-01

423

Alaska looks HOT!  

SciTech Connect

Production in Alaska has been sluggish in recent years, with activity in the Prudhoe Bay region in the North Slope on a steady decline. Alaska North Slope (ANS) production topped out in 1988 at 2.037 MMbo/d, with 1.6 MMbo/d from Prudhoe Bay. This year operators expect to produce 788 Mbo/d from Prudhoe Bay, falling to 739 Mbo/d next year. ANS production as a whole should reach 1.3 MMbo/d this year, sliding to 1.29 MMbo/d in 1998. These declining numbers had industry officials and politicians talking about the early death of the Trans-Alaskan Pipeline System-the vital link between ANS crude and markets. But enhanced drilling technology coupled with a vastly improved relationship between the state government and industry have made development in Alaska more economical and attractive. Alaska`s Democratic Gov. Tommy Knowles is fond of telling industry {open_quotes}we`re open for business.{close_quotes} New discoveries on the North Slope and in the Cook Inlet are bringing a renewed sense of optimism to the Alaska exploration and production industry. Attempts by Congress to lift a moratorium on exploration and production activity in the Arctic National Wildlife Refuge (ANWR) have been thwarted thus far, but momentum appears to be with proponents of ANWR drilling.

Belcher, J.

1997-07-01

424

The Conrad Observatory Research Facility  

NASA Astrophysics Data System (ADS)

The Conrad Observatory in Austria belongs to the group of most modern geophysical observatories worldwide. The observatory is situated 55 km SW of Vienna in the Eastern Alps. Since 2002 - when the observatory was officially opened - several research tasks, projects, training courses and workshops were carried out at this venue. The site is also magnetically very quiet - one of the requirements for establishing the second part of the observatory, which will serve as the magnetic base observatory for Austria in the future. So far, a tunnel of 145 m length equipped with seismometers, 3 boreholes of 100 m depth and one borehole of 50 m depth, as well as a laboratory, where the gravity is continuously moni-tored, are in operation. In addition an outside station has been built according to Austrian standards for reasons of comparison. Refraction profiles and borehole seismic was used to describe the subsurface conditions for H/V measurements and other scientific tasks. The underground observatory provides ex-cellent conditions to test seismometers under controlled conditions, and a newly developed calibration table assists in the determination of the generator constants of seismometers. Internet connection is available together with a re-distributed GPS-timing signal in the observatory. The NERIES Transnational Access activity TA-5 has attracted already project teams from Germany, Slovenia and The Netherlands to conduct specific instrument tests and comparisons between sensors. See also www.zamg.ac.at/conrad_observatory.

Lenhardt, W.; Melichar, P.

2009-04-01

425

Stratospheric Observatory for Infrared Astronomy  

NASA Astrophysics Data System (ADS)

We present one of the new generations of observatories, the Stratospheric Observatory For Infrared Astronomy (SOFIA). This is an airborne observatory consisting of a 2.7-m telescope mounted on a modified Boeing B747-SP airplane. Flying at an up to 45,000 ft (14 km) altitude, SOFIA will observe above more than 99 percent of the Earth's atmospheric water vapor allowing observations in the normally obscured far-infrared. We outline the observatory capabilities and goals. The first-generation science instruments flying on board SOFIA and their main astronomical goals are also presented.

Hamidouche, M.; Young, E.; Marcum, P.; Krabbe, A.

2010-12-01

426

Alaska Resource Data File, Point Lay quadrangle, Alaska  

USGS Publications Warehouse

This report gives descriptions of the mineral occurrences in the Point Lay 1:250,00