Southern California Earthquake Data Center

Significant Earthquakes and Faults

Chronological Earthquake Index

San Jacinto Fault (Terwilliger Valley) Earthquake

Type of Faulting: probably right-lateral strike-slip
Time: March 25, 1937 / 8:49 am, PST
Location: 33° 24.5' N, 116° 16' W 32 km (20 miles) south of Indio about 96 km (60 miles) northeast of San Diego
Magnitude: ML6.0

 

Also known as the Terwilliger Valley Earthquake -- actually a misnomer, since a more accurate recent determination of its epicenter has it located almost 30 km (19 miles) ESE of Terwilliger Valley -- this quake caused very little damage, since the epicentral region was sparsely populated in 1937 (and, even today, is still somewhat remote). A few chimneys were damaged, some plaster was cracked, and a few windows were broken at structures located (relatively) near the epicenter. It was recognized at the time, however, that the quake could have easily caused the kind of damage seen in Santa Barbara in 1925 or in Long Beach in 1933, had it been located in a densely populated area, being nearly the same magnitude as those destructive quakes. This earthquake occurred just after the advent of modern seismology, and was one of the first for which both an accurate epicentral location and a numerical magnitude value (using Charles Richter's newly developed system) were determined -- previously, earthquake "size" was measured by intensity. Intensity is still a valuable tool for the study of earthquakes, but it does not always accurately reflect the true energy-release of an event.

 

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