Alaska Volcano Observatory

Christina Neal

Department:	Alaska Volcano Observatory
Institute:	USGS
Address:	Anchorage, AK 99508
Discipline(s):	Geology Tephra

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Christina (Tina) Neal has been a geologist at the USGS-Anchorage facility of AVO since 1990. Prior to that, Tina was stationed at the Hawaiian Volcano Observatory where she worked on the early years of the 1983-present Kilauea east rift zone eruption and mapped the summit area and southwest rift zone of Kilauea. Since coming to Alaska, Tina has been part of eruption response and geologic investigations of the Redoubt, Spurr, and Augustine events. Geologic mapping and hazard assessment work has taken her to Aniakchak, Black Peak, Dutton, Westdahl, Okmok, Kasatochi, Semisopochnoi, and Little Sitkin Volcanoes. Tina is the main AVO point of contact for the Kamchatkan Volcano Eruptions Response Team (KVERT) and the newly formed Kurile response team (SVERT). >From 1998-2000, Tina was temporarily based in Washington DC as the geoscience advisor to the Office of U.S. Foreign Disaster Assistance (U.S. Agency for International Development). Current research interests include: determining eruptive histories and hazards at selected Alaskan volcanoes, active volcano-ice interactions, tsunami generation associated with caldera forming eruptions, and the use of pyroclast microtextures to infer eruptive processes. Tina also is heavily involved in interagency hazard communications and ash and aviation hazards worldwide.

[Show Publications]

The July-August 2008 hydrovolcanic eruption of Okmok Volcano, Umnak Island, Alaska 4492

Neal, C.A., Larsen, J.F., and Schaefer, Janet, 2009, The July-August 2008 hydrovolcanic eruption of Okmok Volcano, Umnak Island, Alaska: Alaska Geological Society Newsletter, v. 39, n. 5.

2006 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory 4493

Neal, C.A., McGimsey, R.G., Dixon, J.P., Manevich, Alexander, and Rybin, Alexander, 2009, 2006 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Scientific Investigations Report 2008-5214, 102 p., available at http://pubs.usgs.gov/sir/2008/5214/ .

USGS website with links to PDF

Atmospheric contribution of gas emissions from Augustine volcano, Alaska during the 2006 eruption 4389

Airborne surveillance of gas emissions from Augustine for SO2, CO2 and H2S showed no evidence of anomalous degassing from 1990 through May 2005. By December 20, 2005, Augustine was degassing 660 td1 ofSO2, and ten times that by January 4, 2006.

McGee, K.A., Doukas, M.P., McGimsey, R.G., Neal, C.A., and Wessels, R.L., 2008, Atmospheric contribution of gas emissions from Augustine volcano, Alaska during the 2006 eruption: Geophysical Research Letters, v. 35, L03306, doi: 10.1029/2007GL032301, 5 p.
full-text PDF : 165 KB

2005 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory 4388

The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity at or near 16 volcanoes in Alaska during 2005, including the high profile precursory activity associated with the 2005â��06 eruption of Augustine Volcano.

McGimsey, R.G., Neal, C.A., Dixon, J.P., and Ushakov, Sergey, 2007, 2005 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Scientific Investigations Report 2007-5269, 94 p., available at http://pubs.usgs.gov/sir/2007/5269/ .
USGS website with link to PDF

Volcanic disruption of summit ice at Mount Spurr Volcano, Alaska, 2004-2007 4429

Neal, C.A., Coombs, Michelle, Wessels, Rick, and McGimsey, R.G., 2007, Volcanic disruption of summit ice at Mount Spurr Volcano, Alaska, 2004-2007 [abs.]: Geological Society of America - Abstracts with Programs, v. 39, n. 4, p. 20.

Satellite measurement of glaciers on volcanoes in Alaska: building an inventory of ice extent and hazards 4431

Wessels, Rick, Neal, C.A., Waythomas, Christopher, Huggel, Christian, and Dean, Ken, 2007, Satellite measurement of glaciers on volcanoes in Alaska: building an inventory of ice extent and hazards [abs.]: Geological Society of America - Abstracts with Programs, v. 39, n. 4, p. 20.

Eruption warning systems for aviation in Russia: a 2007 status report 4270

Neal, Christina, Girina, Olga, Senyukov, Sergey, Rybin, Alexander, Osiensky, Jeffrey, Hall, Tony, Nelson, Kristine, and Izbekov, Pavel, 2007: Eruption warning systems for aviation in Russia: a 2007 status report: Fourth International Workshop on Volcanic Ash, World Meterological Organization (WMO) in close collaboration with the International Civil Aviation Organziation (ICAO) and the Civil Aviation Authority of New Zealand, Rotorua, New Zealand, 26-20 March, 2007, 8 p., available at http://www.caa.govt.nz/Volcanic_Ash_Workshop/Papers/VAWS4WP0301.pdf .

full-text PDF : 896 KB

An ash fall atlas poster for volcanic hazard education in the U.S. 4367

Neal, Christina, Wallace, Kristi, and Adleman, Jennifer, 2007, An ash fall atlas poster for volcanic hazard education in the U.S.[abs.]: Cities on Volcanoes 5 Conference, Abstracts volume, Shimabara, Japan, abstract number 32-P-07, p. 168 on unpaginated document.

Geothermal disruption of summit glaciers at Mount Spurr Volcano, 2004-6: an unusual manifestation of volcanic unrest 4196

Mount Spurr, a 3,374-m-high stratovolcano in the Cook Inlet region of Alaska, showed signs of volcanic unrest beginning in 2004 and lasting through 2006. These signs included increases in heat flow, seismicity, and gas flux, which we interpret as the results of a magmatic intrusion in mid-2004. In response, debris-laden meltwater beneath the glacier in Mount Spurr's geothermally active summit basin accumulated as the overlying snow and ice melted. As heat output increased, the icecap subsided into a growing cavity over a meltwater lake, similar to that observed during subglacial volcanic activity in Iceland.

Coombs, M.L., Neal, C.A., Wessels, R.L., and McGimsey, R.G., 2006, Geothermal disruption of summit glaciers at Mount Spurr Volcano, 2004-6: an unusual manifestation of volcanic unrest: U.S. Geological Survey Professional Paper 1732-B, 33 p., available at http://pubs.usgs.gov/pp/pp1732/pp1732b/index.html .
website with link to full-text PDF

Quiescent deformation of the Aniakchak Caldera, Alaska, mapped by InSAR 4103

The 10-km-wide caldera of the historically active Aniakchak volcano, Alaska, subsides ~13 mm/yr, based on data from 19 European Remote Sensing Satellite (ERS-1 and ERS- 2) interferometric synthetic aperture radar (InSAR) images from 1992 through 2002. The pattern of subsidence does not reflect the distribution of pyroclastic deposits from the last eruption in 1931 and therefore is not related to compaction of fragmental debris. Weighted least-squares inversion of the deformation maps indicates a relatively constant subsidence rate. Modeling the deformation with a Mogi point source locates the source of subsidence at ~4 km below the central caldera floor, which is consistent with the inferred depth of magma storage before the 1931 eruption. Magmatic CO2 and He have been measured at a warm soda spring within the caldera, and several sub-boiling fumaroles persist elsewhere in the caldera.

Kwoun, Oh-Ig, Lu, Zhong, Neal, Christina, and Wicks, Charles Jr., 2006, Quiescent deformation of the Aniakchak Caldera, Alaska, mapped by InSAR: Geology, v. 34, n. 1, p. 5-8, doi: 10.1130%2FG22015.1.

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 4423

Neal, C., Wallace, K., Albanese, S., Fish, A., and Cahill, C., 2006, 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 [abs.]: Eos, Joint Assembly Supplement, v. 87, abstract V33B-0659.

Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska 4029

"Okmok Volcano is an active volcano located on the northeast end of Umnak Island, about 100 kilometers southwest of Dutch Harbor. The volcano is capped by a large, circular caldera, 10 kilometers in diameter and 500 to 800 meters deep, that formed during catastrophic eruptions about 12,000 and 2,000 years ago. Since then, more than a dozen separate vents within the caldera have erupted, some of them multiple times, to produce lava flows and widespread tephra (volcanic ash) deposits, with the most recent eruption occurring in 1997. Very large floods and lahars also have accompanied past eruptions, one of which destroyed an Aleut village in 1817. Multiple eruptions of lava and ash also have occurred from vents on the volcano's flanks. The volcano's long-term pattern of frequent eruptions, and dramatic intra-caldera deformation and accompanying seismicity since 1997 show that it remains active, and almost certainly will be the site of explosive and nonexplosive eruptions in the future. Understanding the variety of potential hazards associated with different types of volcanic processes typical of Okmok Volcano can help minimize the impacts of future eruptions."

Beget, J.E., Larsen, J.F., Neal, C.A., Nye, C.J., and Schaefer, J.R., 2005, Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska: Alaska Division of Geological & Geophysical Surveys Report of Investigation 2004-3, 32 p., 1 sheet, scale 1:150,000.
full text of report : 3.4 MB
map sheet : 53.2 MB
link to all files for this report on DGGS website

2002 Volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 4071

The Alaska Volcano Observatory (AVO) tracks activity at the more than 40 historically active volcanoes of the Aleutian Arc (fig. 1). As of December 31, 2002, 24 of these volcanoes are monitored with short-period seismometer networks (fig. 2). AVO's monitoring program also includes daily analysis of satellite imagery supported by occasional over flights and compilation of pilot reports,observations of local residents, and observations of mariners. In 2002, AVO responded to eruptive activity or suspect volcanic activity at 6 volcanic centers in Alaska - Wrangell, the Katmai Group, Veniaminof, Shishaldin, Emmons Lake (Hague), and Great Sitkin volcanoes (fig. 1; tables 1, 2).

Neal, C.A., McGimsey, R.G., and Girina, Olga, 2005, 2002 Volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report OF 2004-1058, 55 p., available online at http://pubs.usgs.gov/of/2004/1058/.
full-text PDF : 5.15 MB

2003 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 4098

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 (figs. 1, 2) (Dixon and others, 2004). The AVO core monitoring program also includes daily analysis of satellite imagery, observation over flights, and compilation of pilot reports and reports from local residents and mariners. In 2003, AVO responded to eruptive activity or suspected volcanic activity at or near 10 volcanic centers (fig. 1; tables 1, 2): Wrangell, Redoubt, Iliamna, Augustine, Mageik, Veniaminof, Pavlof, Emmons Lake (Hague), Shishaldin, and Akutan volcanoes. In addition to responding to eruptive activity at Alaska volcanoes, AVO assisted in the disseminaation of information for the Kamchatka Volcanic Eruption Response Team (KVERT) about the 2003 activity of 6 Russian volcanoes: Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, Alaid, and Chikurachki volcanoes (fig. 22; tables 3, 4). Due to prevailing wind directions, erupting Kamchatkan, Kurile Island, and Alaskan volcanoes pose a serious potential threat to aircraft in the North Pacific (fig. 3).

McGimsey, Robert G., Neal, Christina A., and Girina, Olga, 2005, 2003 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report 2005-1310, 62 p., http://pubs.usgs.gov/of/2005/1310/.
website with link to PDF
full-text PDF : 3.54 MB

2004 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory 4099

2004 began quietly in Alaska, continuing a trend of little volcanic unrest that has persisted for several years. On January 9, AVO announced the beginning of formal seismic monitoring of Okmok Volcano following an extended period of calibration and improvement of the seismic network installed initially in 2002-2003. Gareloi and Tanaga volcanoes in the western Aleutians were added to the list of seismically monitored volcanoes in early June following determination of background seismicity. During the remainder of the year, AVO responded to volcanic unrest at three volcanoes in Alaska-Mount Spurr, Veniaminof, and Shishaldin.

Neal, C.A., McGimsey, R.G., Dixon, Jim, and Melnikov, Dimitry, 2005, 2004 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report 2005-1308, 71 p., http://pubs.usgs.gov/of/2005/1308/.
USGS website with link to PDF
full-text PDF : 4.82 MB

The ~400 yr BP caldera-forming eruption of Half Cone Volcano, Aniakchak National Park, Alaska 3805

Browne, B. L., Eichelberger, J. C., Neal, C. A., and Gardner, J. E., 2004, The ~400 yr BP caldera-forming eruption of Half Cone Volcano, Aniakchak National Park, Alaska [abs.]: IAVCEI General Assembly Supplement, p. unknown.

Analysis of composition and chronology of dome emplacement at Black Peak, Alaska utilizing ASTER remote sensing data and field-based studies 4060

"The purpose of this study is to investigate differences in dome mineralogy and alteration using Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) satellite imagery, field observations, and laboratory petrologic and spectrographic analyses of the Black Peak volcano complex, Alaska. Black Peak is a 3.5km-wide-caldera on the Alaska Peninsula. The caldera formed ~4,600 years ago by an eruption that deposited <20km3 of ash-flow tuffs which filled the valleys to the west and north. The floor of the ice-free caldera consists of approximately a dozen overlapping, mainly andesitic lava domes and coulees."

Adleman, J.N., Larsen, J.F., Ramsey, M.S., McGimsey, R.G., and Neal, C.A., 2004, Analysis of composition and chronology of dome emplacement at Black Peak, Alaska utilizing ASTER remote sensing data and field-based studies [abs.]: in Abstract Volume, IAVCEI General Assembly, November 2004, Pucon, Chile, s08c_pf_165.
full-text PDF : 60 KB

Analysis of composition and chronology of dome emplacement at Black Peak, Alaska utilizing ASTER remote sensing data and field-based studies 4061

"The purpose of this study is to investigate differences in dome mineralogy and alteration using Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) satellite imagery, field observations, and laboratory petrologic and spectrographic analyses of the Black Peak volcano complex, Alaska. Black Peak is a 3.5km-wide-caldera on the Alaska Peninsula. The caldera formed ~4,600 years ago by an eruption that deposited <20kmof ash-flow tuffs which filled the valleys to the west and north. The floor of the ice-free caldera consists of approximately a dozen overlapping, mainly andesitic lava domes and coulees."

Adleman, J.N., Larsen, J.F., Ramsey, M.S., McGimsey, R.G., and Neal, C.A., 2004, Analysis of composition and chronology of dome emplacement at Black Peak, Alaska utilizing ASTER remote sensing data and field-based studies [abs.]: in Abstract Volume, IV International Biennial Workshop on Subduction Processes emphasizing the Japan-Kurile-Aleutain Arcs, August 2004, unpaged.
full-text PDF : 16 KB

Headless debris flows from Mount Spurr volcano, Alaska 4091

McGimsey, R., Neal, C., Waythomas, C., Wessels, R., Coombs, M., Wallace, K., 2004, Headless debris flows from Mount Spurr Volcano, Alaska [abs.]: Transactions, American Geophysical Union, v. 85, n. 47, Abstract V43B-1430.

Evidence for dike emplacement beneath Iliamna Volcano, Alaska in 1996 3576

"Two earthquake swarms, comprising 88 and 2833 locatable events, occurred beneath Iliamna Volcano, Alaska, in May and August of 1996. Swarm earthquakes ranged in magnitude from -0.9 to 3.3. Increases in SO2 and CO2 emissions detected during the fall of 1996 were coincident with the second swarm. No other physical changes were observed in or around the volcano during this time period. No eruption occurred, and seismicity and measured gas emissions have remained at background levels since mid-1997."

Roman, D. C., Power, J. A., Moran, S. C., Cashman, K. V., Doukas, M. P., Neal, C. A., and Gerlach, T. M., 2004, Evidence for dike emplacement beneath Iliamna Volcano, Alaska in 1996: Journal of Volcanology and Geothermal Research, v. 130, n. 3-4, p. 265-284.

The Alaska Volcano Observatory - Expanded monitoring of volcanoes yields results 3624

"Recent explosive eruptions at some of Alaska's 41 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, S. R., McGimsey, R. G., and Neal, C. A., 2004, The Alaska Volcano Observatory - Expanded monitoring of volcanoes yields results: U.S. Geological Survey Fact Sheet FS 2004-3084, 2 p.
full-text HTML
full-text PDF : 260 KB

2001 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 4004

"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 daily analysis of satellite imagery, observation overflights, compilation of pilot reports and reports from local residents and mariners. In 2001, AVO responded to eruptive activity or suspected volcanic activity at or near 8 volcanic centers; Snowy and Kukak of the Kamai Group, Pavlof, Frosty, Shishaldin, Makushin, Okmok, Cleveland, and Great Sitkin volcanoes."

McGimsey, R.G., Neal, C.A., and Girina, Olga, 2004: 2001 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report OF 2004-1453, 53 p.
website with link to PDF
full-text PDF on AVO's server : 2.67 MB

Analysis of composition and chronology of dome emplacement at Black Peak, Alaska utilizing ASTER remote sensing data and field-based studies 4062

Adleman, J.N., Larsen, J.F., Ramsey, M.S., McGimsey, R.G., and Neal, C.A., 2003, Analysis of composition and chronology of dome emplacement at Black Peak, Alaska utilizing ASTER remote sensing data and field-based studies [abs.]: in Fall meeting supplementary, Eos, v. 84, n. 46, Abstract V31G-07.

website with full text

Preliminary investigations of the ~4600 BP caldera-forming eruption and subsequent post-caldera activity 4063

McGimsey, R.G., Neal, C.A., Adleman, J.N., Larsen, J.F., and Ramsey, M.S., 2003, Preliminary investigations of the ~4600 BP caldera-forming eruption and subsequent post-caldera activity [abs.]: in Fall meeting supplement, Eos, v. 84, n. 46, V42B-0342.

website with full text

Deciphering silicic dome emplacement processes in the northern Pacific: Quantitative analyses of high resolution satellite and field-based data 4064

Ramsey, M.S., Dehn, J., Adleman, J.N., Larsen, J.F., McGimsey, R.G., Neal, C.A., and Wessels, R., 2003, Deciphering silicic dome emplacement processes in the northern Pacific: Quantitative analyses of high resolution satellite and field-based data [abs.]: in Fall meeting supplement, Eos, v. 84, n. 46, V51F-0346.

website with full text

1998 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 3513

"The Alaska Volcano Observatory (AVO) monitors the more than 40 historically active volcanoes of the Aleutian Arc. Of these, 20 are monitored with short-period seismic instrument networks as of the end of 1998. The AVO core monitoring program also includes daily analysis of satellite imagery, overflights, compilation of pilot reports and observations from local residents and ship crews. In 1998, AVO responded to eruptive activity or suspected volcanic activity at or near 7 volcanic centers; Shrub mud volcano, Augustine, Becharof Lake near Ukinrek Maars, Chiginagak, Shishaldin, Akutan, and Korovin."

McGimsey, R. G., Neal, C. A., and Girina, Olga, 2003, 1998 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report OF 03-0423, 35 p.
web site with link to PDF
full-text PDF : 1.40 MB

The Kamchatkan Volcanic Eruption Response Team (KVERT) 3389

"Russia's Kamchatka Peninsula is home to 29 active volcanoes, including 7 snow-capped stratocones more than 10,000 ft (3,000 m) high. Several eruptions each year in Kamchatka produce ash clouds that threaten the safety of air travel across the North Pacific, including travel between the United States and Russia and Japan. The Kamchatkan Volcanic Eruption Response Team (KVERT), created in 1993 through a cooperative effort of Russian and U.S. scientists, monitors the volcanoes of Kamchatka to provide warnings and rapid reporting of eruptions."

Kirianov, V. Y., Neal, C. A., Gordeev, E. I., and Miller, T. P., 2002, The Kamchatkan Volcanic Eruption Response Team (KVERT): U.S. Geological Survey Fact Sheet FS 064-02, 2 p.
full-text PDF : 455 KB

The 1931 eruption of Aniakchak Volcano, Alaska 3491

Nicholson, R. S., Neal, C. A., and Gardner, J. E., 2002, The 1931 eruption of Aniakchak Volcano, Alaska [abs.]: Eos, v. 83, n. 47, p. F1465.

Volcano hazard monitoring and ash warnings in the North Pacific; an evolving, multi-agency, international collaboration 3639

Neal, C. A., 2002, Volcano hazard monitoring and ash warnings in the North Pacific; an evolving, multi-agency, international collaboration [abs.]: Abstracts with Programs - Geological Society of America, v. 34, n. 5, p. 11.

Satellite imagery proves essential for monitoring erupting Aleutian volcano 2937

"Mt. Cleveland is one of more than 40 active volcanoes in Alaska that is monitored by the Alaska Volcano Observatory (AVO). It is located on the western half of Chuginadak, a remote and uninhabited island in the east central Aleutians that lies 1526 km southwest of Anchorage. The closest inhabited community, Nikolski, is 75 km to the east on Umnak Island (Figure 1)."

Dean, Kenneson, Dehn, Jonathan, McNutt, Steve, Neal, Christina, Moore, Richard, and Schneider, Dave, 2002, Satellite imagery proves essential for monitoring erupting Aleutian volcano: Eos, v. 83, n. 22, p. 241, 246-247.

Areal distribution, thickness, mass, volume, and grain size of tephra-fall deposits from the 1992 eruptions of Crater Peak Vent, Mt. Spurr volcano, Alaska 2938

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

McGimsey, R. G., Neal, C. A., and Riley, C. M., 2001, Areal distribution, thickness, mass, volume, and grain size of tephra-fall deposits from the 1992 eruptions of Crater Peak Vent, Mt. Spurr volcano, Alaska: U.S. Geological Survey Open-File Report OF 01-0370, 38 p.
website with links to PDFs
full-text PDF : 10.8 MB

Preliminary volcano-hazard assessment for Aniakchak Volcano, Alaska 718

"Aniakchak is an active volcano located on the Alaska Peninsula 670 kilometers southwest of Anchorage. The volcano consists of a dramatic, 10-kilometer-diameter, 0.5 to 1.0-kilometer-deep caldera that formed during a catastrophic eruption 3,500 years ago. Since then, at least a dozen separate vents within the caldera have erupted, often explosively, to produce lava flows and widespread tephra (ash) deposits. The most recent eruption at Aniakchak occurred in 1931 and was one of the largest explosive eruptions in Alaska in the last 100 years. Although Aniakchak volcano presently shows no signs of unrest, explosive and nonexplosive eruptions will occur in the future. Awareness of the hazards posed by future eruptions is a key factor in minimizing impact."

Neal, Christina, McGimsey, R. G., Miller, T. P., Riehle, J. R., and Waythomas, C. F., 2001, Preliminary volcano-hazard assessment for Aniakchak Volcano, Alaska: U.S. Geological Survey Open-File Report OF 00-0519, 35 p.
website with links to PDFs
full-text PDF : 24.2 MB
map sheet plate PDF (for viewing) : 3.1 MB

Isomass maps of the tephra fall deposits from the 1992 eruptions of Crater Peak Vent, Mount Spurr Volcano, Alaska 3716

McGimsey, R. G., Neal, C. A., and Riley, C. M., 2000, Isomass maps of the tephra fall deposits from the 1992 eruptions of Crater Peak Vent, Mount Spurr Volcano, Alaska [abs.]: Eos, v. 81, n. 48, p. 1312.

Communication of volcano hazards: approach of the Alaska Volcano Observatory 3721

Neal, C. A., 2000, Communication of volcano hazards: approach of the Alaska Volcano Observatory [abs.]: Abstracts with Programs - Geological Society of America, v. 32, n. 7, p. 335.

Use of FLIR observations during eruption response at two Alaskan volcanoes 857

McGimsey, R. G., Schneider, D. J., Neal, C. A., and Roach, A. L., 1999, Use of FLIR observations during eruption response at two Alaskan volcanoes [abs.]: Eos, v. 80, n. 46, p. 1146.

Tephra-fall deposits from the 1992 eruption of Crater Peak, Alaska: implications of clast textures for eruptive processes 128

The 1992 eruption of Crater Peak, Mount Spurr, Alaska, involved three subplinian tephra-producing events of similar volume and duration. The tephra consists of two dense juvenile clast types that are identified by color, one tan and one gray, of similar chemistry, mineral assemblage, and glass composition. In two of the eruptive events, the clast types are strongly stratified with tan clasts dominating the basal two thirds of the deposits and gray clasts the upper one third.

Gardner, C. A., Cashman, K. V., and Neal, C. A., 1998, Tephra-fall deposits from the 1992 eruption of Crater Peak, Alaska: implications of clast textures for eruptive processes: Bulletin of Volcanology, v. 59, n. 8, p. 537-555.

Tsunami generation by pyroclastic flow during the 3500-year B.P. caldera-forming eruption of Aniakchak Volcano, Alaska 185

A discontinuous pumiceous sand, a few centimeters to tens of centimeters thick, is located up to 15 m above mean high tide within Holocene peat along the northern Bristol Bay coastline of Alaska. The bed consists of fine-to-coarse, poorly to moderately wellsorted, pumice-bearing sand near the top of a 2-m-thick peat sequence. The sand bed contains rip-up clasts of peat and tephra and is unique in the peat sequence. Major element compositions of juvenile glass from the deposit and radiocarbon dating of enclosing peat support correlation of the pumiceous sand with the caldera-forming eruption of Aniakchak Volcano.

Waythomas, C. F., and Neal, C. A., 1998, Tsunami generation by pyroclastic flow during the 3500-year B.P. caldera-forming eruption of Aniakchak Volcano, Alaska: Bulletin of Volcanology, v. 60, n. 2, p. 110-124.

Pre-eruptive temperatures for postcaldera magmas of Aniakchak Volcano, Alaska 825

Bacon, C. R., Neal, C. A., Nye, C. J., and McGimsey, R. G., 1997, Pre-eruptive temperatures for postcaldera magmas of Aniakchak Volcano, Alaska [abs.]: Eos, v. 78, n. 46, p. 792-793.

New geologic map of Aniakchak Caldera, Alaska 1002

Neal, C. A., McGimsey, R. G., Miller, T. P., Nye, C. J., Bacon, C. R., and Felger, T. J., 1997, New geologic map of Aniakchak Caldera, Alaska [abs.]: Eos, v. 78, n. 46, p. 816.

Pavlof darkens the Alaskan sky 2113

Neal, C. A., 1997, Pavlof darkens the Alaskan sky: Earth in Space, v. 9, n. 8, p. 6-9.

Origin of dense juvenile tephra-fall clasts 2854

Gardner, C. A., Cashman, K. V., and Neal, C. A., 1997, Origin of dense juvenile tephra-fall clasts [abs.]: in IAVCEI General Assembly, Abstracts, p. 113.

Preliminary volcano-hazard assessment for Redoubt Volcano, Alaska 713

"Redoubt Volcano is a stratovolcano located within a few hundred kilometers of more than half of the population of Alaska. This volcano has erupted explosively at least six times since historical observations began in 1778. The most recent eruption occurred in 1989-90 and similar eruptions can be expected in the future. The early part of the 1989-90 eruption was characterized by explosive emission of substantial volumes of volcanic ash to altitudes greater than 12 kilometers above sea level and widespread flooding of the Drift River valley. Later, the eruption became less violent, as developing lava domes collapsed, forming short-lived pyroclastic flows associated with low-level ash emission. Clouds of volcanic ash had significant effects on air travel as they drifted across Alaska, over Canada, and over parts of the conterminous United States causing damage to jet aircraft. Economic hardships were encountered by the people of south-central Alaska as a result of ash fallout. Based on new information gained from studies of the 1989-90 eruption, an updated assessment of the principal volcanic hazards is now possible. Volcanic hazards from a future eruption of Redoubt Volcano require public awareness and planning so that risks to life and property are reduced as much as possible."

Waythomas, C. F., Dorava, J. M., Miller, T. P., Neal, C. A., and McGimsey, R. G., 1997, Preliminary volcano-hazard assessment for Redoubt Volcano, Alaska: U.S. Geological Survey Open-File Report OF 97-857, 40 p., 1 plate, scale unknown.
full-text PDF : 1.76 MB
map sheet plate PDF : 5.61 MB

Tsunami generation during the 3500 yr B.P. caldera-forming eruption of Aniakchak Volcano 1000

Waythomas, C. F., and Neal, C. A., 1997, Tsunami generation during the 3500 yr B.P. caldera-forming eruption of Aniakchak Volcano [abs.]: Eos, v. 78, n. 46, p. 816.

Preliminary volcano-hazard assessment for Pavlof Volcano, Alaska 721

Waythomas, C. F., Miller, T. P., McGimsey, R. G., and Neal, C. A., 1997, Preliminary volcano-hazard assessment for Pavlof Volcano, Alaska: U.S. Geological Survey Open-File Report OF 97-0135, unpaged, 1 plate, scale 1:375,000.

What is the Alaska Volcano Observatory? 1057

Neal, C. A., 1997, What is the Alaska Volcano Observatory?: U.S. Geological Survey Open-File Report OF 97-0443, 2 p.

Volcanic ash - Danger to aircraft in the North Pacific 2114

"The world's busy air traffic corridors pass over hundreds of volcanoes capable of sudden, explosive eruptions. In the United States alone, aircraft carry many thousands of passengers and millions of dollars of cargo over volcanoes each day. Volcanic ash can be a serious hazard to aviation even thousands of miles from an eruption. Airborne ash can diminish visibility, damage flight control systems, and cause jet engines to fail. USGS and other scientists with the Alaska Volcano Observatory are playing a leading role in the international effort to reduce the risk posed to aircraft by volcanic eruptions."

Neal, C. A., Casadevall, T. J., Miller, T. P., Hendley, J. W. II., and Stauffer, P. H., 1997, Volcanic ash - Danger to aircraft in the North Pacific: U.S. Geological Survey Fact Sheet FS 30-0097, 2 p.
full-text PDF : 196 KB

Volcanoes of the Alaska Peninsula and Aleutian Islands selected photographs 636

"Alaska is home to more than 40 active volcanoes, many of which have erupted violently and repeatedly in the last 200 years. This compact disc (CD-ROM) contains 97 digital images created from 35-mm slides scanned by a Kodak PIW film scanner. These pictures are but a small fraction of thousands taken by Alaska Volcano Observatory scientists, other researchers, and private citizens. Photographs were selected for inclusion in this collection to portray Alaska's volcanoes, to document recent eruptive activity, and to illustrate the range of volcanic phenomena observed in Alaska."

Neal, Christina, and McGimsey, R. G., 1997, Volcanoes of the Alaska Peninsula and Aleutian Islands selected photographs: U.S. Geological Survey Digital Data Series DDS 0040, 1 CD-ROM.
website with links to HTML album, PDF, and individual images in a variety of formats
directory of high-resolution images (PCD format)
web browser photo album
PDF : 27 MB
directory of PDF slideshow files
directory of small screen images (JPG)
directory of large screen images (JPG)
captions file : 44 KB

1996 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 686

"During 1996, the Alaska Volcano Observatory (AVO) responded to eruptive activity, anomalous seismicity, or suspected volcanic activity at 10 of the approximately 40 active volcanic centers in the state of Alaska. These events included a dramatic volcano-seismic crisis at Akutan and a vigorous strombolian eruption at Pavlof. As part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team; Miller and Kurianov, 1993), AVO staff also disseminated information about eruptions and other volcanic unrest at six volcanic centers on the Kamchatka Peninsula and in the Kurile Islands."

Neal, Christina, and McGimsey, R. G., 1997, 1996 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report OF 97-0433, 34 p.
website with PDF and ASCII links
full-text PDF : 795 KB
ASCII full-text

Use of SAR data to study active volcanoes in Alaska 103

Dean, K. G., Neal, C., Doukas, M., Engle, K., and Lu, Z., 1996, Use of SAR data to study active volcanoes in Alaska: Earth Observation Quarterly, v. 53, p. 21-23.

Use of SAR data to study active volcanoes in Alaska 110

Dean, K. G., Engle, K., Lu, Z., Eichelberger, J., Neal, C., and Doukas, M., 1996, Use of SAR data to study active volcanoes in Alaska: in Circumpolar symposium, 4, Proceedings, Lyngby, Denmark, Apr. 29-May 1, 1996, Remote sensing of the polar environments, v. 391, Noordwijk, European Space Agency, p.153-158.

Seguam 3376

Neal, C. A., 1996, Seguam: in Annual report of the world volcanic eruptions in 1993, Bulletin of Volcanic Eruptions, v. 33, p. 90-91.

Makushin 3377

Neal, C. A., 1996, Makushin: in Annual report of the world volcanic eruptions in 1993, Bulletin of Volcanic Eruptions, v. 33, p. 91-92.

Shishaldin 3378

Neal, C. A., 1996, Shishaldin: in Annual report of the world volcanic eruptions in 1993, Bulletin of Volcanic Eruptions, v. 33, p. 93.

Veniaminof 3379

Neal, C. A., 1996, Veniaminof: in Annual report of the world volcanic eruptions in 1993, Bulletin of Volcanic Eruptions, v. 33, p. 94-96.

A catastrophic flood caused by drainage of a caldera lake at Aniakchak Volcano, Alaska, and implications for volcanic hazards assessment 66

Waythomas, C. F., Walder, J. S., McGimsey, R. G., and Neal, C. A., 1996, A catastrophic flood caused by drainage of a caldera lake at Aniakchak Volcano, Alaska, and implications for volcanic hazards assessment: Geological Society of America Bulletin, v. 108, n. 7, p. 861-871.

1993 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory 687

During 1993, the Alaska Volcano Observatory (AVO) responded to episodes of eruptive activity or false alarms at nine volcanic centers in the state of Alaska. Additionally, as part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also responded to eruptions on the Kamchatka Peninsula, details of which are summarized in Miller and Kirianov (1993). In 1993, AVO maintained seismic instrumentation networks on four volcanoes of the Cook Inlet region--Spurr, Redoubt, Iliamna, and Augustine--and two stations at Dutton Volcano near King Cove on the Alaska Peninsula. Other routine elements of AVO's volcano monitoring program in Alaska include periodic airborne measurement of volcanic SO2 and CO2 at Cook Inlet volcanoes (Doukas, 1995) and maintenance of a lightning detection system in Cook Inlet (Paskievitch and others, 1995).

Neal, C. A., McGimsey, R. G., and Doukas, M. P., 1996, 1993 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report OF 96-0024, 21 p.
website with PDF and HTML links
full-text PDF : 1149 KB
HTML full-text

Photographs of the 1989-90 eruptions of Redoubt Volcano, Alaska 692

Roach, A. L., Neal, C. A., and McGimsey, R. G., 1996, Photographs of the 1989-90 eruptions of Redoubt Volcano, Alaska: U.S. Geological Survey Open-File Report OF 96-689, 30 p.

Volcanoes of the Wrangell Mountains and Cook Inlet Region, Alaska-selected photographs 637

"Alaska is home to more than 40 active volcanoes, many of which have erupted violently and repeatedly in the last 200 years. This compact disc (CD-ROM) contains 97 digital images created from 35-mm slides scanned by a Kodak PIW film scanner. These pictures are but a small fraction of thousands taken by Alaska Volcano Observatory scientists, other researchers,and private citizens. Photographs were selected for inclusion in this collection to portray Alaska's volcanoes, to document recent eruptive activity, and to illustrate the range of volcanic phenomena observed in Alaska."

Neal, Christina, and McGimsey, Robert, 1996, Volcanoes of the Wrangell Mountains and Cook Inlet Region, Alaska-selected photographs: U.S. Geological Survey Digital Data Series DDS 0039, 1 CD-ROM.
website with links to HTML album, PDF, and individual images in a variety of formats
web browser photo album
print-resolution PDF : 21.2 MB
screen-resolution PDF : 1.8 MB
directory to slideshow pdf file
directory of small screen images (jpg)
directory of large screen images (jpg)
directory to full-resolution images (PCD format)

1995 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory 680

"The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity (SVA) at 6 volcanic centers in 1995 (tables 1, 2): Mount Martin (Katmai Group), Mount Veniaminof, Shishaldin, Makushin, Kliuchef/Korovin, and Kanaga. Of these, AVO has a realtime, continuously recording seismic network only at the Katmai Group. The remaining unmonitored volcanoes are located in sparsely populated and uninhabited areas of the Alaska Peninsula and the Aleutian Islands. For these volcanoes, the AVO monitoring program relies mainly on pilot reports, observations of local residents and ship crews, and analysis of satellite images. The phrase "suspected volcanic activity", used to characterize several responses, is an eruption report or report of unusual activity that is subsequently determined to be normal or enhanced fumarolic activity, weather-related phenomena, or a non-volcanic event."

McGimsey, R. G., and Neal, Christina, 1996, 1995 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report OF 96-0738, 22 p.
website with PDF and HTML links
full-text PDF : 1036 KB
full-text HTML

The last 3400 years at Aniakchak caldera, Alaska 1892

Neal, C. A., McGimsey, R. G., Waythomas, C. F., Miller, T. P., and Nye, C. J., 1995, The last 3400 years at Aniakchak caldera, Alaska [abs.]: Abstracts with Programs - Geological Society of America, v. 27, n. 5, p. 67.

Volcanigenic tsunami from Alaskan volcanoes: geologic evidence from Bristol Bay and Cook Inlet, Alaska 2252

Waythomas, C. F., Neal, C. A., McGimsey, R. G., Dorava, J. M., Lemke, K. J., and Vanderpool, A. M., 1995, Volcanigenic tsunami from Alaskan volcanoes: geologic evidence from Bristol Bay and Cook Inlet, Alaska [abs.]: Eos, v. 76, n. 46, p. 291.

Mechanics of magma/ water interaction, Ukinrek Maars, Alaska 2256

Ort, M. H., Wohletz, K. H., Neal, C. A., and McConnell, V. S., 1995, Mechanics of magma/ water interaction, Ukinrek Maars, Alaska [abs.]: in International Union of Geodesy and Geophysics, General Assembly, 21, International Union of Geodesy and Geophysics: XXI general assembly; abstracts, Boulder, CO, July 2-14, 1995, Week A, p. 467.

1994 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory 527

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

Neal, C. A., Doukas, M. P., and McGimsey, R. G., 1995, 1994 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Open-File Report OF 95-0271, 18 p.
website with PDF link
full-text PDF : 3 MB

Extreme tholeiitic to calcalkaline transition at Aniakchak volcano, east-central Aleutian arc 1894

Nye, C. J., Neal, C. A., Miller, T. P., and McGimsey, R. G., 1995, Extreme tholeiitic to calcalkaline transition at Aniakchak volcano, east-central Aleutian arc [abs.]: Abstracts with Programs - Geological Society of America, v. 27, n. 5, p. 69.

Pyroclastic flows of the 1992 Crater Peak eruptions: distribution and origin 1985

"Crater Peak, a 2,309-m-high satellite cone on the south flank of the Mount Spurr volcanic center 125 km west of Anchorage erupted on June 27, August 18, and the night of September 16-17, 1992 (see Eichelberger and others, this volume) after 39 years of quiescence. The three eruptions were similar in that they each produced vulcanian to subplinian eruption columns as high as 18 km above sea level, formed extensive bomb fields, lasted 3 to 4 hours, erupted pyroclastic material only, had ejecta bulk volumes of 44 to 56 x 106 m3 each (see Eichelberger and others, this volume), and were of andesitic composition."

Miller, T. P., Neal, C. A., and Waitt, R. B., 1995, Pyroclastic flows of the 1992 Crater Peak eruptions: distribution and origin: in Keith, T. E. C., (ed.), The 1992 eruptions of Crater Peak Vent, Mount Spurr volcano, Alaska, U.S. Geological Survey Bulletin B 2139, p. 81-87.
full-text PDF : 509 KB

Tephra-fall deposits from the 1992 eruptions of Crater Peak, Mount Spurr volcano, Alaska: a preliminary report on distribution, stratigraphy, and composition 1986

"After 39 years of quiescence, the Crater Peak vent on the south flank of Mount Spurr volcano reawakened with a series of three short lived but violent eruptions of andesitic tephra on June 27, August 18, and September 16-17 of 1992 (Eichelberger and others, this volume; Alaska Volcano Observatory, 1993). Each eruption lasted 3.5 to 4.0 hours and generated vulcanian to subplinian eruption columns that reached altitudes of more than 14 km above sea level (ASL). Carried downwind, these tephra plumes resulted in narrowly distributed fall deposits composed principally of poorly vesiculated, crystal-rich juvenile andesite that ranged in size from coarse bombs to fine ash. Plumes from the three eruptions extended north, northeast, and east away from the volcano. Two of the three 1992 events deposited significant amounts of fallout tephra onto the most heavily populated areas of south-central Alaska (fig. 1A)."

Neal, C. A., McGimsey, R. G., Gardner, C. A., Harbin, M. L., and Nye, C. J., 1995, Tephra-fall deposits from the 1992 eruptions of Crater Peak, Mount Spurr volcano, Alaska: a preliminary report on distribution, stratigraphy, and composition: in Keith, T. E. C., (ed.), The 1992 eruptions of Crater Peak Vent, Mount Spurr volcano, Alaska, U.S. Geological Survey Bulletin B 2139, p. 65-79.
full-text PDF : 579 KB

Volcanic activity in Alaska: Summary of events and response of the Alaska Volcano Observatory 1992 2107

McGimsey, R. G., Neal, C. A., and Doukas, M. P., 1995, Volcanic activity in Alaska: Summary of events and response of the Alaska Volcano Observatory 1992: U.S. Geological Survey Open-File Report OF 95-83, 26 p.

USGS website with link to .DJVU files and images

Whole-rock major- and trace-element chemistry of 1992 ejecta from Crater Peak, Mount Spurr volcano, Alaska 2117

"Mount Spurr volcano, 125 km west of Anchorage, is the next-to-last Holocene volcano at the northeastern end of the Aleutian arc. It is about 100 km above the Benioff zone and 500 km from the trench in a direction parallel to the movement between the Pacific and North American plates. The region surrounding Mount Spurr is underlain by a Jurassic to mid-Tertiary granitic batholith, which intrudes Paleozoic to Mesozoic limestone, basalt, and flysch of generally low metamorphic grade (Wilson and others, 1985)."

Nye, C. J., Harbin, M. L., Miller, T. P., Swanson, S. E., and Neal, C. A., 1995, Whole-rock major- and trace-element chemistry of 1992 ejecta from Crater Peak, Mount Spurr volcano, Alaska: in Keith, T. E. C., (ed.), The 1992 eruptions of Crater Peak Vent, Mount Spurr volcano, Alaska, U.S. Geological Survey Bulletin B 2139, p. 119-128.
full-text PDF : 503 KB

Lightning associated with the August 18, 1992, eruption of Crater Peak vent, Mount Spurr volcano, Alaska 2119

"Although the occurrence of lightning in volcanic eruption clouds is well documented, few attempts have been made to use lightning detection and location to monitor eruptions. Such a monitoring approach could potentially allow for the detection of an ash cloud even when meteorological conditions might prevent observations from satellites and ground-based radar. In 1990, the Alaska Volcano Observatory (AVO) experimented with a lightning detection system (LDS) used by the Bureau of Land Management (BLM) in their forest fire program. BLM's network is configured to locate typical meteorologic lightning strikes that could potentially cause forest fires."

Paskievitch, J. F., Murray, T. L., Hoblitt, R. P., and Neal, C. A., 1995, Lightning associated with the August 18, 1992, eruption of Crater Peak vent, Mount Spurr volcano, Alaska: in Keith, T. E. C., (ed.), The 1992 eruptions of Crater Peak Vent, Mount Spurr volcano, Alaska, U.S. Geological Survey Bulletin B 2139, p. 179-182.
full-text PDF : 90 KB

Topographic maps of Novarupta dome and selected portions of the Valley of Ten Thousand Smokes, Katmai National Park and Preserve, Alaska 2124

Strobe, Robert, Rice, William, and Neal, C. A., 1995, Topographic maps of Novarupta dome and selected portions of the Valley of Ten Thousand Smokes, Katmai National Park and Preserve, Alaska: U.S. Geological Survey Open-File Report OF 95-0619, unpaged, 4 plates, scale 1:48,000 and 1:2,400.

Repeated volatile zonation in the tephra deposits from the 1992 eruption of Crater Peak, Alaska: magma chamber or magma transport processes? 2222

Gardner, C. A., Cashman, K. V., and Neal, C. A., 1995, Repeated volatile zonation in the tephra deposits from the 1992 eruption of Crater Peak, Alaska: magma chamber or magma transport processes? [abs.]: Abstracts with Programs - Geological Society of America, v. 27, n. 5, p. 20.

High stand and catastrophic draining of intracaldera Surprise Lake, Aniakchak volcano, Alaska 163

"Because of their basin-like shape, calderas on many Alaskan volcanoes are geomorphic repositories for water, ice, and snow. The heat flux associated with these volcanoes enhances melting of ice and snow, and caldera lakes commonly result. The caldera rim is a type of natural dam that may impound a substantial amount of water depending on the size of the caldera and the integrity of the bedrock that forms the rim. Failure of a caldera dam and subsequent catastrophic drainage of the intracaldera lake can pose a serious hazard to life and property situated in the flood path (Bolt and others, 1977, p. 94-95). In this report of our preliminary observations, we present geomorphic and stratigraphic evidence for (1) a former extensive intracaldera lake at Aniakchak volcano, (2) catastrophic drainage of this lake by failure of the caldera rim dam, and (3) possible linkages between dam failure and the recent eruptive history of the volcano."

McGimsey, R. G., Waythomas, C. F., and Neal, C. A., 1994, High stand and catastrophic draining of intracaldera Surprise Lake, Aniakchak volcano, Alaska: in Till, A. B. and Moore, T. E., (eds.), Geologic studies in Alaska by the U.S. Geological Survey, 1993, U.S. Geological Survey Bulletin B 2107, p. 59-71.
full-text PDF : 15 MB

Unusual ice diamicts emplaced during the December 15, 1989 eruption of Redoubt Volcano, Alaska 182

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.

Waitt, R. B., Neal, C. A., Gardner, C. A., Pierson, T. C., and Major, J. J., 1994, Unusual ice diamicts emplaced during the December 15, 1989 eruption of Redoubt Volcano, Alaska: in Chouet, B. A. and Miller, T. P., (eds.), The 1989-1990 eruptions of Redoubt Volcano, Alaska, Journal of Volcanology and Geothermal Research, v. 62, n. 1, p. 409-428.

High stand and catastrophic draining of intracaldera Surprise Lake, Aniakchak Crater, Alaska 1888

McGimsey, R. G., Waythomas, C. F., and Neal, C. A., 1994, High stand and catastrophic draining of intracaldera Surprise Lake, Aniakchak Crater, Alaska [abs.]: Abstracts with Programs - Geological society of America, v. 26, n. 7, p. A138.

Aniakchak Caldera - working in one of Alaska's most spectacular active volcanoes 2757

Neal, C. A., and McGimsey, R. G., 1994, Aniakchak Caldera - working in one of Alaska's most spectacular active volcanoes: Alaska Geological Society Newsletter, v. 24, n. 2, p. 5-6.

Proximal pyroclastic deposits from the 1989-1990 eruption of Redoubt volcano, Alaska - stratigraphy, distribution, and physical characteristics 118

More than 20 eruptive events during the 1989-1990 eruption of Redoubt Volcano emplaced a complex sequence of lithic pyroclastic-flow, -surge, -fall, ice-diamict, and lahar deposits mainly on the north side of the volcano. The deposits record the changing eruption dynamics from initial gas-rich vent-clearing explosions to episodic gas-poor lava-dome extrusions and failures. The repeated dome failures produced lithic pyroclastic flows that mixed with snow and glacial ice to generate lahars that were channeled off Drift glacier into the Drift River valley. Some of the dome failures occurred without precursory seismic warning and appeared to result solely from gravitational instability.

Gardner, C. A., Neal, C. A., Waitt, R. B., and Janda, R. J., 1994, Proximal pyroclastic deposits from the 1989-1990 eruption of Redoubt volcano, Alaska - stratigraphy, distribution, and physical characteristics: in Miller, T. P. and Chouet, B. A., (eds.), The 1989-1990 eruptions of Redoubt Volcano, Alaska, Journal of Volcanology and Geothermal Research, v. 62, n. 1, p. 213-250.

Complex interactions of ground water and basaltic magma during the eruption of the Ukinrek maars, Alaska 2288

Ort, M. H., Wohletz, K. H., and Neal, C. A., 1994, Complex interactions of ground water and basaltic magma during the eruption of the Ukinrek maars, Alaska [abs.]: Abstracts with Programs - Geological Society of America, v. 26, n. 7, p. 378.

What is the Alaska Volcano Observatory? 2115

Neal, Christina, and Doukas, Mike, 1994, What is the Alaska Volcano Observatory?: U.S. Geological Survey Fact Sheet FS 94-0071, 2 p.

Extreme and abrupt transition from tholeiitic to calcalkaline volcanism at Aniakchak Volcano, eastern Aleutian Arc 532

Nye, C. J., Neal, C. A., and McGimsey, R. G., 1993, Extreme and abrupt transition from tholeiitic to calcalkaline volcanism at Aniakchak Volcano, eastern Aleutian Arc [abs.]: Eos, v. 74, n. 43, p. 674.

Effects of prevailing wind on the distribution of surge and fallout deposits an Ukinrek Maars, Alaska 534

Ort, M. H., Neal, C. A., McConnell, V. S., Wohletz, K. H., Duffield, W. A., and Lescinsky, D. T., 1993, Effects of prevailing wind on the distribution of surge and fallout deposits an Ukinrek Maars, Alaska [abs.]: Eos, v. 74, n. 43, p. 639.

Volatile zonation in the Crater Peak magma: evidence from 1992 tephra-fall deposits 2855

Gardner, C. A., Neal, C. A., and McGimsey, R. G., 1993, Volatile zonation in the Crater Peak magma: evidence from 1992 tephra-fall deposits [abs.]: Eos, v. 74, p. 621.

Photographs of the 1992 eruptions of Crater Peak, Spurr Volcano, Alaska 734

Neal, C. A., McGimsey, R. G., Doukas, M. P., and Ellersieck, Inyo, 1993, Photographs of the 1992 eruptions of Crater Peak, Spurr Volcano, Alaska: U.S. Geological Survey Open-File Report OF 93-707, 9 p.

website with photos

The 1992 eruptions of Mt. Spurr Volcano, Alaska: an overview 1488

Miller, T. P., McNutt, S. R., Eichelberger, J. C., and Neal, C. A., 1992, The 1992 eruptions of Mt. Spurr Volcano, Alaska: an overview [abs.]: Eos, v. 73, n. 43, p. 342.

The August 18, 1992 eruption of Mount Spurr Volcano, Alaska: tephra-fall stratigraphy, distribution and impact 1489

Neal, C. A., McGimsey, R. G., Doukas, M. P., Miller, T. P., Richter, D., Paskievitch, J. F., and Ellersieck, I., 1992, The August 18, 1992 eruption of Mount Spurr Volcano, Alaska: tephra-fall stratigraphy, distribution and impact [abs.]: Eos, v. 73, n. 43, p. 342.

Lightning associated with the 18 August, 1992 eruption of Mount Spurr 1497

Paskievitch, J. F., Murray, T. L., Hoblitt, R., and Neal, C. A., 1992, Lightning associated with the 18 August, 1992 eruption of Mount Spurr [abs.]: Eos, v. 73, n. 43, p. 346.

Post-caldera eruptive history of Aniakchak caldera, Alaska 1891

Neal, C. A., McGimsey, R. G., Braitseva, O., Miller, T. P., Eichelberger, J. C., and Nye, C., 1992, Post-caldera eruptive history of Aniakchak caldera, Alaska [abs.]: Eos, v. 73, n. 43, p. 645.

Alaska Volcano Observatory summary report: May 1, 1991 - June 30, 1991 4526

Neal, C.A. (compiler), 1991, Alaska Volcano Observatory summary report: May 1, 1991 - June 30, 1991: Alaska Volcano Observatory bimonthly report series, 8 p.

Alaska Volcano Observatory summary report: September 1, 1991 - October 31, 1991 4528

Neal, C.A. (compiler), 1991, Alaska Volcano Observatory summary report: September 1, 1991 - October 31, 1991: Alaska Volcano Observatory bimonthly report series, 7 p.

Geophysical expedition to Novarupta II 326

Eichelberger, J. C., Neal, C. A., Paskievitch, J. F., Papike, J. J., and Hildreth, W., 1990, Geophysical expedition to Novarupta II [abs.]: Eos, v. 71, n. 43, p. 1690.

Stratigraphy of proximal pyroclastic deposits from the eruption of Redoubt Volcano, Alaska, December 14, 1989-April 21, 1990 369

Gardner, C. A., Waitt, R. B., and Neal, C. A., 1990, Stratigraphy of proximal pyroclastic deposits from the eruption of Redoubt Volcano, Alaska, December 14, 1989-April 21, 1990 [abs.]: Eos, v. 71, n. 43, p. 1706.

Characteristics of proximal pyroclastic deposits from the eruption of Redoubt Volcano, Alaska, January 2, 1990-April 21, 1990 528

Neal, C. A., Gardner, C. A., Waitt, R. B., and Miller, T. P., 1990, Characteristics of proximal pyroclastic deposits from the eruption of Redoubt Volcano, Alaska, January 2, 1990-April 21, 1990 [abs.]: Eos, v. 71, n. 43, p. 1706.

Emission rates of sulfur dioxide and carbon dioxide from Redoubt Volcano, Alaska during the 1989-1990 eruptions 1635

Casadevall, T. J., Neal, C. A., McGimsey, R. G., Doukas, M. P., and Gardner, C. A., 1990, Emission rates of sulfur dioxide and carbon dioxide from Redoubt Volcano, Alaska during the 1989-1990 eruptions [abs.]: Eos, v. 71, n. 43, p. 1702.

Unusual ice conglomerate emplaced during the 15 December 1989 eruption of Redoubt Volcano, Alaska 1642

Waitt, R. B., Gardner, C. A., Janda, R. J., Miller, T. P., Major, J. J., Pierson, T. C., Neal, C. A., and Vallance, J. W., 1990, Unusual ice conglomerate emplaced during the 15 December 1989 eruption of Redoubt Volcano, Alaska [abs.]: Eos, v. 71, n. 43, p. 1706.

Alaska Volcano Observatory fall report: October 1, 1990 - December 31, 1990 4527

Neal, C.A., and Power, J. (compilers), 1990, Alaska Volcano Observatory fall report: October 1, 1990 - December 31, 1990: Alaska Volcano Observatory bimonthly report series, 8 p.

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