Geological Origins
The Puget Sound area, where this earthquake occurred, is prone to deep earthquakes due to the Juan de Fuca tectonic plate's subduction under the North American Plate at 3.5 to 4.5 cm. a year as part of the Cascadia subduction zone, which causes stress in the former as it sinks into the mantle. As an intraslab earthquake, it was produced by a change in volume as rock changed from one form to another. Similar significant earthquakes occurred in the same general region on April 29, 1965 (magnitude 6.5, depth 63 km (39 mi)), and April 13, 1949 (magnitude 7.1, depth 53 km (33 mi)).
Read more about this topic: 2001 Nisqually Earthquake
Famous quotes containing the words geological and/or origins:
“The crystal sphere of thought is as concentrical as the geological structure of the globe. As our soils and rocks lie in strata, concentric strata, so do all men’s thinkings run laterally, never vertically.”
—Ralph Waldo Emerson (1803–1882)
“Grown onto every inch of plate, except
Where the hinges let it move, were living things,
Barnacles, mussels, water weeds—and one
Blue bit of polished glass, glued there by time:
The origins of art.”
—Howard Moss (b. 1922)