Seismic imaging of the Medicine Lake Caldera
Medicine Lake Volcano, a broad shield volcano about 50 km east of Mount Shasta in northern California, produced rhylotic eruptions as recently as 400 years ago. Because of this recent activity it is of considerable interest to producers of geothermal energy. The USGS and LLNL conducted an active seismic experiment designed to explore the area beneath and around the caldera. This experiment had two purposes: To produce high-quality velocity and attenuation images of the young magma body presumed to be the source for the young volcanic features, and to collect a dataset that can be used to develop and test seismic imaging methods that may be useful for understanding other geothermal systems. Eight large explosions were detonated in a 50 km radius circle around the volcano, a distance chosen to produce strong upward traveling signals through the area of interest. The data were inverted using Aki's method to produce three-dimensional velocity and attenuation images of the sub-surface. Preliminary interpretation shows low velocity and attenuation on the flanks of the volcano, and coincident high attenuation values and low velocities (-20%) from 3 to 5 km beneath the center of the caldera. This zone may be a region of partial melt which fed the youngest eruptions.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6386104
- Report Number(s):
- UCRL-96509; CONF-8704110-11; ON: DE87011567
- Resource Relation:
- Conference: 5. geothermal program review, Washington, DC, USA, 14 Apr 1987; Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
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