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2004 September 28 17:15:24 UTC

Earthquake Details

  • This event has been reviewed by a seismologist.
  • This earthquake is the anticipated Parkfield earthquake, Mw 6.0 on the San Andreas fault. It ruptured roughly the same segment of the fault that broke in 1966. The earthquake occurred at 10:15 AM PDT on September 28, 2004. Its hypocenter was located at 35 degrees, 49 minutes north, 120 degrees 22 minutes west, at a depth of 8 km or 5 miles. From this point, about 7 miles SW of the town of Parkfield, it ruptured primarily northwest along the San Andreas fault. Strong shaking during this event lasted for about 10 seconds. This earthquake is the seventh in a series of repeating earthquakes on this stretch of the fault. The previous events were in 1857, 1881, 1901, 1922, 1934, and 1966.
  • Tuesday, September 28, 2004 at 17:15:24 UTC
  • Tuesday, September 28, 2004 at 10:15:24 AM at epicenter
Location35.815°N, 120.374°W
Depth7.9 km (4.9 miles)
Distances 30 km (20 miles) SW of Avenal, California
35 km (25 miles) S of Coalinga, California
35 km (25 miles) ENE of Paso Robles, California
325 km (200 miles) SSE of SACRAMENTO, California
Location Uncertaintyhorizontal +/- 0.4 km (0.2 miles); depth +/- 0.6 km (0.4 miles)
ParametersNST=248, Nph=248, Dmin=3 km, Rmss=0.11 sec, Gp= 94°,
M-type=regional moment magnitude (Mw), Version=7
Event IDnc51147892
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