Medicine Lake
Find U.S. Volcano
Medicine Lake volcano is situated just east of the Cascade Volcanic Arc axis in northern California's high desert 55 km (35 mi), northeast of Mount Shasta.
Quick Facts
Location: California, Siskiyou & Modoc Counties
Latitude: 41.611° N
Longitude: 121.554° W
Elevation: 2,412 (m) 7,913 (f)
Volcano type: composite (red map area)
Composition: basalt to rhyolite
Most recent eruption: 950 years ago
Nearby towns: Malin, Merrill, Tulelake, Dorris, Klamath Falls (OR)
Threat Potential: High*
*based on the National Volcano Early Warning System
Summary
Also known as the Medicine Lake Highlands, this volcanic region covers a total area of about 2,200 km2 (850 mi2), extending approximately 80 km (50 mi) north-south and 50 km (30 mi) east-west. A shallow, but wide (7x12 km, 4.3x7.5 mi) caldera basin containing its namesake lake is located at the summit of the volcano. Intermittent, mostly effusive (non-explosive) eruptions over the last half-million years produced this large, shield-shaped volcano. In the last 13,000 years, effusive flank eruptions created expansive lava flows with single flows covering as much as 195 km2 (75 mi2). Two-thirds of Lava Beds National Monument, on the north flank of the volcano, is covered by one such flow. Seven of the nine eruptions of the last 5,200 years, however, included an early explosive phase. The two youngest sent ash tens of miles downwind during their explosive phases before switching to slow effusion of thick, glassy-looking lava flows (obsidian) forming Little Glass Mountain about 1,000 years ago, and, Glass Mountain about 950 years ago. Exploratory drilling and geophysical studies reveal a high temperature geothermal system below Medicine Lake volcano fueled by a deeper zone of partially molten rock (magma). Ground surveys by USGS scientists show that the center of the volcano is slowly subsiding, due to motions on through-going regional faults and weakening of the rocks by high heat flow. Most notable seismically over the last three decades were a series of shallow earthquakes in 1988-89 (magnitudes of 4.1 and less).
News
Examining early 20th-century reports of "activity" at Medicine Lake's Glass Mountain
Fall into a burning (curtain) of fire with fissure eruptions
Which U.S. volcanoes pose a threat?
Publications
California’s exposure to volcanic hazards
The potential for damaging earthquakes, landslides, floods, tsunamis, and wildfires is widely recognized in California. The same cannot be said for volcanic eruptions, despite the fact that they occur in the state about as frequently as the largest earthquakes on the San Andreas Fault. At least ten eruptions have taken place in the past 1,000 years, and future volcanic eruptions are inevitable.The
2018 update to the U.S. Geological Survey national volcanic threat assessment
When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update
Database for potential hazards from future volcanic eruptions in California
More than 500 volcanic vents have been identified in the State of California. At least 76 of these vents have erupted, some repeatedly, during the past 10,000 yr. Past volcanic activity has ranged in scale and type from small rhyolitic and basaltic eruptions through large catastrophic rhyolitic eruptions. Sooner or later, volcanoes in California will erupt again, and they could have serious impact
