The 1992 Eruptions of Crater Peak Vent, Mount Spurr Volcano, Alaska: Chronology and Summary

232 Pages·2010·49.23 MB·English

lOUNT SPURR VOLCANO,
LASKA I '
i 4
f I
U.S. GEOLOGICAL SURVEY BULLETIN 2139
Cover Ash cloud rising from Crater Peak vent of Mount Spurr volcano,
Alaska, during the eruption on August 18, 1992. Crater Peak is not visible
in image. A pyroclastic flow that descended the volcano's flank produced
the smaller steam and ash cloud shown at lower right of large cloud.
Photograph taken by Robert G. McGimsey.
THE 1992 ERUPTIONS OF
CRATER PEAK VENT,
MOUNT SPURR VOLCANO,
ALASKA
Terry E.G. Keith, Editor
U.S. GEOLOGICAL SURVEY BULLETIN 2139
UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1995
U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary
U.S. GEOLOGICAL SURVEY
Gordon P. Eaton, Director
For sale by
U.S. Geological Survey, Information Services
Box 25286, Federal Center
Denver, CO 80225
Any use of trade, product, or firm names in this publication is for descriptive purposes only and does
not imply endorsement by the U.S. Government
Cover designed by Glenn Schumacher
Text and illustrations edited by Carolyn Donlin
Library of Congress Cataloging-in-Publication Data
The 1992 eruptions of Crater Peak vent, Mount Spurr volcano, Alaska /
Terry E.G. Keith, editor.
p. cm. (U.S. Geological Survey bulletin ; 2139)
Includes bibliographical references (p. - ).
Supt.ofDocs.no.: 119.3:2139
1. Spurr, Mount (Alaska) Eruption, 1992. I. Keith, Terry E. C.
II. Series.
QE75.B9 no. 2139
[QE523.S73]
557.3 s dc20
[551.21 F097983] 95-43967
CIP
CONTENTS
1. The 1992 Eruptions of Crater Peak Vent, Mount Spurr Volcano, Alaska: Chronology
and Summary /
By John C. Eichelberger, Terry E.G. Keith, Thomas P. Miller, and Christopher J. Nye
2. Real-time C-band Radar Observations of 1992 Eruption Clouds from Crater Peak,
Mount Spurr Volcano, Alaska 19
By William I. Rose, Alexander B. Kostinski, and Lee Kelley
3. Tracking of 1992 Eruption Clouds from Crater Peak Vent of Mount Spurr Volcano,
Alaska, Using AVHRR 27
By David J. Schneider, William I. Rose, and Lee Kelley
4. Explosive Emissions of Sulfur Dioxide from the 1992 Crater Peak Eruptions, Mount
Spurr Volcano, Alaska 37
By Gregg J.S. Bluth, Courtney J. Scott, lan E. Sprod, Charles C. Schnetzler,
Arlin J. Krueger, and Louis S. Walter
5. Sulfur Dioxide Scrubbing During the 1992 Eruptions of Crater Peak, Mount Spurr
Volcano, Alaska 47
By Michael P. Doukas and Terrence M. Gerlach
6. Chemistry of Crater Lake Waters Prior to the 1992 Eruptions of Crater Peak, Mount
Spurr Volcano, Alaska 59
By Terry E.G. Keith, J. Michael Thompson, and Robert G. McGimsey
7. Tephra-fall Deposits from the 1992 Eruptions of Crater Peak, Mount Spurr
Volcano, Alaska: A Preliminary Report on Distribution, Stratigraphy, and
Composition 65
By Christina A. Neal, Robert G. McGimsey, Cynthia A. Gardner, Michelle L. Harbin,
and Christopher J. Nye
8. Pyroclastic Flows of the 1992 Crater Peak Eruptions: Distribution and Origin 81
By Thomas P. Miller, Christina A. Neal, and Richard B. Waitt
9. Ballistic Showers During Crater Peak Eruptions of Mount Spurr Volcano,
Summer 1992 89
By Richard B. Waitt, Larry G. Mastin, and Thomas P. Miller
10. Hybrid Wet Flows Formed by Hot Pyroclasts Interacting with Snow During the 1992
Eruptions of Crater Peak, Mount Spurr Volcano, Alaska 707
By Richard B. Waitt
11. Whole-rock Major- and Trace-element Chemistry of 1992 Ejecta from Crater Peak,
Mount Spurr Volcano, Alaska 119
By Christoper J. Nye, Michelle L. Harbin, Thomas P. Miller, Samuel E. Swanson, and
Christina A. Neal
12. Use of Volcanic Glass from Ash as a Monitoring Tool: An Example from the 1992
Eruptions of Crater Peak, Mount Spurr Volcano, Alaska 129
By Samuel E. Swanson, Michelle L. Harbin, and James R. Riehle
13. Preliminary Petrology and Chemistry of Proximal Eruptive Products: 1992 Eruptions
of Crater Peak, Mount Spurr Volcano, Alaska 139
By Michelle L. Harbin, Samuel E. Swanson, Christoper J. Nye, and Thomas P. Miller
14. Seismicity and Forecasting of the 1992 Eruptions of Crater Peak Vent, Mount Spurr
Volcano, Alaska: An Overview 149
By John A. Power, Arthur D. Jolly, Robert A. Page, and Stephen R. McNutt
15. Preliminary Analyses of Volcanic Tremor Associated with 1992 Eruptions of Crater
Peak, Mount Spurr Volcano, Alaska 161
By Stephen R. McNutt, Guy C. Tytgat, and John A. Power
16. Lightning Associated with the August 18, 1992, Eruption of Crater Peak Vent, Mount
Spurr Volcano, Alaska 179
By John F. Paskievitch, Thomas L. Murray, Richard P. Hoblitt, and
Christina A. Neal
17. Lahars from the 1992 Eruptions of Crater Peak, Mount Spurr Volcano, Alaska 183
By David F. Meyer and Dennis C. Trabant
18. June 29, 1993, Outburst Flood from Kidazgeni Glacier, Mount Spurr Volcano, Alaska 199
By Christopher J. Nye, William R. Hammond, Guy C. Tytgat, and
Joseph M. Dorava
19. Effects of the 1992 Crater Peak Eruptions on Airports and Aviation Operations in
the United States and Canada 205
By Thomas J. Casadevall and M. Dennis Krohn
List of Contributors 227
Appendix Time Conversion Chart 223
The 1992 Eruptions of Crater Peak Vent, Mount Spurr
Volcano, Alaska: Chronology and Summary
By John C. Eichelberger, Terry E.G. Keith, Thomas P. Miller, and Christopher J. Nye
CONTENTS effects it deposited 3 mm of ash on Anchorage, 125 km
east of the volcano. Proximal pyroclastic flows accom
panied the August and September eruptions. In all erup-
s rac - tions, lahars and debris flows descended Crater Peak's
. , . , , south flank, and some reached the Chakachatna River.
Acknowledgment 1 '. . . . ,,,.,«
GeologicsettmgandhistoryofMountSpurrvolcano------ -2 Real-time seismic monitoring tracked the 10-
Role of the Alaska Volcano Observatory----------4 month crescendo of precursory earthquakes and al-
1992 Eruptions monitoring and response chronology 4 lowed timely warning of the increasing unrest to State
Pre-emption period 4 and Federal government officials, the military, air car-
June 27 eruption 11 riers, and local citizens. This monitoring was augmented
August 18 eruption 11 with other types of observations and provided the ba-
September 16-17 eruption 12 sis for accurate eruption advisories that minimized eco-
Seismic swarms: October 2-6, November 9-10, and nomic losses. In particular, because of an efficient ash-
December 21-27 12 cioud warning system in Alaska and new awareness
General characteristics of the eruptions __________ 13 Qf ^ blem Qf ash douds within ^ aviation CQm_
Analysis of response 13 . . , JTT -JLII r
\ ...... , munity, no lets were damaged. Unavoidable losses of
Interpretation of seismicity 14 .,_ Jn . . . , _ , , ~
Evidence from hydrothermal activity and gas emission- 14 $5 to 8 mllllon Were sustained from the August ashfa11
Visual observation of eruptions -------.......... 14 on Anchorage and the Matanuska-Susitna Valley, both
Detection of volcanic lightning _____________ 15 °f which make up the State of Alaska's center of popu-
Radar observation of eruptive columns 15 lation and economic activity. Additional but unevaluated
Projection of plume paths 15 costs were incurred from flight delays in large North
Tracking of plumes by satellite 15 American airports to the south and east as ash clouds
Dissemination of information ----- 16 of the August and September eruptions passed over-
Economic effects of the 1992 eruptions 16 head
Vblcanological implications of the 1992 eruptions 17
References cited 18
INTRODUCTION
ABSTRACT
The Crater Peak vent of Mount Spurr volcano,
located 125 km west of Anchorage (figs. 1, 2) and
Following 39 years of inactivity, Crater Peak vent
last active in 1953 (Juehle and Coulter, 1955; Wilcox,
on the south flank of Mount Spurr volcano burst into
1959), erupted three times in 1992 following 10 months
eruption at 7:04 a.m. Alaska daylight time (ADT) on
of heightened seismicity. The first eruption occurred
June 27, 1992. This and subsequent eruptions on Au
on June 27, 1992, and was followed by similar events
gust 18 and September 16-17 were subplinian, had a
on August 18 and September 16-17, 1992. This pa
volcano explosivity index (VEI) of 3, and lasted about
per provides an overview of these eruptions and the
4 hours. The June, August, and September eruptions
Alaska Volcano Observatory's response to them.
released 44, 52, and 56 million m3 (12, 14, and 15
million m3 dense rock equivalent or DRE) of andes-
itic (57 weight percent SiO2) tephra, respectively and ACKNOWLEDGMENT
drove tephra columns 14,000 to 15,000 m above sea
level. The August eruption had the most far-reaching This work was supported by the U.S. Geologi
cal Survey Volcano Hazards and Geothermal Studies
Manuscript approved for publication May 19, 1995. Program and by the State of Alaska.
THE 1992 ERUPTIONS OF CRATER PEAK VENT, MOUNT SPURR, ALASKA
154°W 152°W 150°W
62°N
Latest activity
A Historic time
A Holocene
0 50
61°N
60°N
Augustine
Volcano Bay
59°N
ount Douglas
guyak Crater
Figure 1. Index map showing volcanoes and population centers of the Cook Inlet region, Alaska.
GEOLOGIC SETTING AND HISTORY but before Holocene time, the volcano collapsed south
OF MOUNT SPURR VOLCANO ward in a manner similar to Bezymianny Volcano in
Kamchatka, Russia (Gorshkov, 1959). The debris ava
Mount Spurr sits 100 km above the Wadati- lanche generated at Mount Spurr had a minimum runout
Benioff zone and 500 km inboard of the Aleutian Trench of 25 km by 6 km and left the volcano with a horse
(Jacob and others, 1977) on a basement of mainly in shoe-shaped caldera rim. Collapse was followed im
trusive rocks (Nye and Turner, 1990). Its large stra- mediately by eruption of more silicic (60-63 weight
tovolcano edifice, built of two-pyroxene andesite (58 percent SiO2) andesitic ash-flow tuffs. A large dome
60 weight percent SiO2), began to form before 255,000 complex, which now forms Mount Spurr's 3,374-m
yr ago (Nye and Turner, 1990). Pyroclastic rocks domi summit, grew in the center of the caldera probably
nate the lower part of the volcano, and lava flows no later than 5,000 yr ago (Riehle, 1985). The com
dominate the upper part. Within the past 58,000 yr plex consists of two-pyroxene silicic andesite, chemi-
n O ZO O O on C
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t
i
s
o
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PLANATION Glacial ice Alluvium and drift Crater Peak deposits Mount Spurr dome Pyroclastic fan Ancestral Mount Spu Nonvolcanic baseme Crater rim Projected fault Seismic station 5km ur interval 1000ft
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61-2 61*1 Fig
THE 1992 ERUPTIONS OF CRATER PEAK VENT, MOUNT SPURR, ALASKA
cally similar to the ash-flow tuffs (Nye and Turner, populace. Accordingly, the Cook Inlet region presents
1990). A basaltic-andesite satellitic cone developed at the greatest array of volcano hazards in Alaska and
the same time in the caldera breach. The present Crater is the focus of AVO's efforts.
Peak represents a second period of satellite cone-build AVO distributes updates (fig. 3) each Friday to
ing at the same location; it reaches an elevation of summarize the weekly status of the monitored Cook
2,309 m, 3.5 km south of Mount Spurr's summit. Crater Inlet volcanoes and any reported activity of unmonitored
Peak consists of lavas and pyroclastic flows of mafic volcanoes on the Alaska Peninsula and Aleutian Is
andesite (53-57 weight percent SiO2. Nye and Turner, lands. During periods of volcanic unrest and eruption
1990). The 40 tephra units correlated to this vent range crises, additional updates are issued when significant
in age from 5,000 yr to present (Riehle, 1985). Erup changes in activity should be made known to the public
tion products that are apparent mixtures of Crater Peak (Brantley, 1990). Updates were issued frequently to a
and summit dome complex magmas indicate that the prioritized list of well over 100 recipients during the
two systems were partly coeval (Nye and Turner, 1990). Crater Peak eruptions. AVO at Fairbanks faxes to the
Prior to 1992, the only witnessed eruption of local Federal Aviation Administration (FAA), the lo
Mount Spurr occurred on July 9, 1953. This eruption cal National Weather Service (NWS), Alaska Depart
also issued from the Crater Peak vent and consisted ment of Emergency Services (ADES), local military
of two main explosive pulses, followed by steam and bases, Governor's and State offices, television and radio
minor ash emission. The eruption cloud rose to over stations, and airlines. AVO at Anchorage faxes to the
20,000 m above sea level and deposited 3 to 6 mm of local FAA, the local NWS, local military bases, USGS
andesitic (55 weight percent SiO2) ash on Anchorage offices, other federal agencies, television and radio
(Juehle and Coulter, 1955; Wilcox, 1959). A debris stations, news wire services, and airlines. Updates are
flow dammed the Chakachatna River downslope from also distributed by electronic mail to the volcano in
Crater Peak, and the dam created an 8-km-long lake. formation networks.
The dam was overtopped and breached within a week. A level of concern color code was established
during the Redoubt Volcano eruptions to quickly and
simply convey AVO's evaluation of eruption poten
tial and eruption severity (Brantley, 1990; Miller and
ROLE OF THE ALASKA VOLCANO
Chouet, 1994). This code was modified slightly for
OBSERVATORY
use with the Crater Peak eruptions (fig. 4). When a
volcanic crisis begins, telephone calls are made to Fed
eral, State, and local agencies with critical public safety
The Alaska Volcano Observatory (AVO) was es
responsibilities to give the level of concern color code
tablished in 1988, following the 1986 eruption of Au
as the update is being prepared. A calldown proce
gustine Volcano; the observatory conducted its first
dure, likewise established for the Redoubt Volcano erup
full eruption response with the Redoubt Volcano epi
tions (Brantley, 1990; Miller and Chouet, 1994), was
sode of 1989-90 (Miller and Chouet, 1994). AVO is
used for the Crater Peak eruptions. Responsibility for
a cooperative program of the U.S. Geological Survey
calls are shared between AVO at Anchorage and AVO
(USGS), University of Alaska Fairbanks Geophysical
at Fairbanks, so all concerned agencies are contacted
Institute (UAFGI), and Alaska Division of Geologi
within minutes.
cal and Geophysical Surveys (ADGGS). AVO is sup
ported by both the Department of Interior through the
USGS Volcano Hazards and Geothermal Studies Pro 1992 ERUPTIONS MONITORING AND
gram and by the State of Alaska. AVO's primary mis RESPONSE CHRONOLOGY
sion is to communicate timely warnings of unrest and
PRE-ERUPTION PERIOD
potential eruption of Alaska's volcanoes and to in
vestigate the fundamental processes of hazardous vol- Early indication of unrest at Mount Spurr was a
canism, with a view toward improved eruption warn conspicuous swarm of volcano-tectonic (VT) earth
ings and hazard assessments. quakes during the last half of August 1991 (table 1;
Since World War II, Anchorage has become the Power and others, this volume). Unlike swarms that
population and economic center of Alaska; over half had occurred in 1982 and 1989, this one was directly
the population of the State is currently concentrated under Crater Peak within a volume that had been
in the Anchorage area. Three of the Cook Inlet vol aseismic for at least a decade (Jolly and others, 1994),
canoes Augustine Volcano, Redoubt Volcano, and and it was followed by caldera-wide seismicity. By
Mount Spurr are frequently active. Within the past February of 1992, seismic activity had increased to
decade, their eruptions have produced ash clouds that such a level that discussions of Mount Spurr's unrest
were hazardous to aircraft as well as to the general were included in AVO's weekly updates. Through April