Notable Earthquake of the Week

Walker Pass M6.3 Earthquake  

On March 15, 1946, a strong earthquake measuring M6.3 occurred along the southeastern margin of the Sierra Nevada Mountains, near Lake Isabella. The Walker Pass earthquake was centered about 32 miles east-northeast of town in a remote region of Upper South Fork Valley of the Kern River, near Walker Pass.

The depth was determined to be about 21 km beneath the surface and fault plane solution suggested predominantly normal-slip with a slight right-lateral strike-slip motion along a northerly trending fault plane. No surface fault ruptures were ever discovered. It was followed a robust aftershock sequence which lasted for years and consisted of five M5's and at least two dozen M4's most of which happened during the first few weeks of the main shock.

The quake was felt as far away as north San Diego and San Luis Obispo and caused considerable damage to the sparse developments in the area. Walls were cracked, windows were shattered and items there thrown from cabinets and counter tops. Landslides were common in the mountainous regions. Cracks formed in the ground and the concrete along the Los Angeles Aqueduct.

Although the quake was centered in the Sierra Nevada geologic province, the quake was more characteristic of events in the Basin and Range Province.



Also this week in Seismo-History was a
M5.3 temblor in the Homestead Valley of the Southern California High Desert on March 15, 1979. The quake was felt from Los Angeles to western Arizona and southern Nevada. It was the strongest of several shocks which caused moderate damage to buildings at Landers and Yucca Valley and formed minor surface fault ruptures along the Pipes Wash Fault near Pipes Wash - site of the powerful M7.3 Landers earthquake in 1992. Damage included downed chimneys, cracked walls and broken windows. Electrical and telephone service was temporarily disrupted.
 
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