Medicine Lake Volcano Medicine Lake Volcano Medicine Lake Volcano is a large shield volcano in northeastern California about northeast of Mount Shasta. The volcano is located in a zone of east-west crustal extension east of the main axis of the Cascade Volcanic Arc and the Cascade Range. The thick shield is from east to west and from north to south, and covers more than . The underlying rock has downwarped by under the center of the volcano. The volcano is primarily composed of basalt and basaltic andesite lava flows, and has a caldera at the center. The Medicine Lake shield rises about above
Zuidwal volcano Zuidwal volcano The Zuidwal volcano is an extinct volcano in the Netherlands at more than below ground under the Wadden Sea, between Harlingen and Vlieland, just south west of the island Griend. The volcano was last active during the late Jurassic, (about 160 - 148 Ma ago) and has since been covered by about of sedimentary rock, most of it shale and sandstone from the Cretaceous. The volcano was discovered in 1970 when the French oil company Elf Aquitaine was doing test drills in the Wadden Sea, hoping to find a gas field that a seismic survey had indicated. To