Quarry Blast

The seismogram below is a portion of the daily record for August 14, 2000 from Fremont Peak station HFP. The prominent signature shortly after 20:18:22 UTC has many of the characteristics of a small nearby earthquake. It has, for instance, an abrupt onset and an exponential decay indicative of an earthquake having a duration magnitude of 1.7. Based upon it's magnitude (<2.0), location (within a km of a known quarry location), and time (mid-day is a common time for quarry blasts), however, this event is probably a quarry blast from a quarry near Natividad, CA.

Helicorder display