Report Number: 12806
Reporting Year: 1997
Permit Number: CRLA1997ASPA
Date Received: Jan 01, 1998
Principal Investigator:
Charles Bacon,
U.S. Geological Survey,
Menlo park, California
Park-assigned Study Id. #
CRLA1997ASPA
Permit Expiration Date:
Jan 01, 1998
Permit Start Date:
Jan 01, 1997
Study Starting Date:
Jan 01, 1997
Study Ending Date:
Jan 01, 1997
Study Status:
Completed
Activity Type:
Other
Subject/Discipline:
Geology / General
Objectives:
To document the growth and
evolution of Mount Mazama, the volcanic complex in which Crater Lake caldera
lies, in order to define processes that led to an accumulation of a large volume
of silicic magma in the upper crust. Secondary goals are to further knowledge of
catastrophic eruptions, such as the one that resulted in the collapse of the
caldera.
Findings and Status: Work continues
on preparation of the 1:24,000 scale geologic map for publication. Digital files
of the geologic map nd all eleven geologic panoramas of the caldera walls are
being edited in ArcInfo. These will be published in color. A volcano and
earthquake hazards assessment of the Crater Lake area was published in
cooperation with USGS colleagues at the Cascades Volcano Observatory. A poster
on this subject was presented at the 1997 General Assembly of the International
Association of Volcanology and Chemistry of the Earth's Interior in Puerto
Vallarta, Mexico. The hazard report contains information on probability of
future volcanic eruptions, the types of volcanic events that may occur, hazard
zones for different kinds of volcanic activity, potential for earthquakes on the
West Klamath Lake fault zone (which passes within 1 km of Rim Village) and other
faults, and possible consequences of earthquake shaking, including landslides
from the caldera walls and waves generated on Crater Lake. Also published in
1997 was a major paper on primitive magmas at Crater Lake and four other Cascade
volcanic centers. Renee Bourgeois, University of Oregon, began a Masters thesis
project on the Cleetwood pumice fall deposit under the direction of Prof. K.V.
Cashman and C.R. Bacon. Duane Champion (USGS, Menlo Park) and Bacon, assisted by
Bourgeois, collected approximately 60 oriented 1" diameter core samples of the
lava flows and dome of the subglacially-erupted Bear Bluff complex, west of
Annie Creek, for paleomagnetic study in Menlo Park. Preliminary results indicate
rhyodacite and andesite of this complex record the same paleomagnetic direction,
a finding consistent with field observations that imply both magma types were
erupted concurrently.
For this study, were one or
more specimens collected and removed from the park but not destroyed during
analyses?
No
Funding provided this
reporting year by NPS:
0
Funding provided this
reporting year by other sources:
0
Full name of college or
university: n/a
Annual funding provided by
NPS to university or college this reporting year: 0
