| The pattern of historical ground deformation, seismicity, and crustal structure near Medicine Lake volcano illustrates a close relation between magmatism and tectonism near the margin of the Cascade volcanic chain and the Basin and Range tectonic province. Between leveling surveys in 1954 and 1989 the summit of Medicine lake volcano subsided 389 +/- 43 mm with respect to a reference bench mark 40 km to the southwest (average rate = 11.1 +/- mm/yr). A smaller survey across the summit caldera in 1988 suggests that the subsidence rate was 15-28 mm/yr during 1988-1989. -- Dzurisin, et.al., 1991 |
[Map,40K,InlineGIF]
Location map showing the Medicine Lake volcano - Mount Shasta area of the
southern Cascade Range, northern California.
Pale green pattern indicates extent of lavas
of Medicine Lake volcano. Heavy lines are faults, with bar and ball on
downthrown side (Gay and Aune [1958] and air photograph interpretation).
Blue line represents the 1954-1989 leveling route.
Contour interval is 1000 feet (305 m).
-- Modified from: Dzurisin, et.al., 1991,
IN: Journal of Geophysical Research, v.96, no.B10
