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R/V Fast Eddy on Medicine Lake
Medicine Lake, located in Siskiyou County in northern California, sits at an elevation of about 7,000 ft, within the ancient caldera of the Medicine Lake volcano complex. Medicine Lake volcano is a Pleistocene and Holocene shield volcano located in the Cascade Range, 50 km northeast of Mount Shasta. Medicine Lake volcano lavas cover about 2,000 km2, and the total volume of the volcano is estimated at 600 km³, larger than Mount Shasta, which is the largest of the Cascade stratocones. The most recent Medicine Lake volcano eruption occurred about 0.9 ka. At least 17 eruptions have occurred since 12 ka, or between one and two eruptions per century on average. More information is available online. Detailed bathymetric and geopulse-reflection profile data were acquired along with surface-water temperature and temperature-depth profiles. The reflection data were particularly interesting, revealing structure to 40 m and more beneath the lake bottom. The lake ‹sedimentsÅ proved, unfortunately, relatively impenetrable to the small hand-coring instruments available, and further investigation will have to await a vibracoring effort planned for next year. Once the lake sediments are sampled, USGS researchers hope to use them to unravel the volcanic and climate history of the region and the geochemical behavior of mercury in volcanic terrains. Medicine Lake is a popular camping and fishing spot, and considerable public interest has been expressed in a new bathymetric map to replace the old one that dates back to 1955. Using the bathymetric data collected last September, we have just completed such a map, soon to be published.
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![]() in this issue:
Medicine Lake, CA
Earth Science Week in Woods Hole ![]() |