Here are some of sample seismograms, recorded by the
Seismic Network (BDSN), using
Make Your Own
Seismogram. You can view current seismograms at
which displays waveforms from 9 stations, updated every
- 04/25/92 Cape Mendocino, CA
During 1992, the largest and most destructive earthquake in northern and
central California was the Mw 7.0 event which occurred at 1806 UTC on
April 25, 1992 near Petrolia and in the area of the Mendocino Triple
Junction. This earthquake occurred along the
boundary zone between the Gorda and North American plates and its moment
tensor solution, determined from broadband waveform inversion, is
consistent with a low angle reverse mechanism on the Cascadia
Subduction Zone. The earthquake had a very energetic aftershock
sequence, including two large strike-slip earthquakes (both Mw 6.5)
which occurred in the Gorda plate just north of the Mendocino Fracture
Zone and approximately 35 km WNW on the mainshock focus.
- 01/17/94 Northridge, CA
This record displays 24 hours of data, beginning approximately 8 hours
before the mainshock, recorded by the BDSN station BKS at a distance
of 525 km. The Mw 6.7 event was immediately followed by magnitude 5.9
aftershock which is lost in the arrivals from the main event. Aftershocks
are visible at 15:07 (Ml 4.2), 20:46 (Ml 4.9), and 23:33 (Ml 5.6).
- 06/09/94 Bolivia
This record displays 8 hours of waveforms recorded at BDSN station CMB
on the day of the Bolivian earthquake. This Mw 8.3 earthquake
occurred at the depth of 637 km and was widely felt in North America
(as far away as Montreal, Canada). Seismologists are studying this
earthquake to learn more about the physics of earthquake rupture and
the processes of subduction.
- 06/26/94 Berkeley, CA
On June 26, three small earthquakes located in Berkeley, CA, were recorded
by the BDSN station MHC at a distance of 86 km. The first event registered
a local magnitude of 3.2 and was followed 5 minutes later by a 2.5
earthquake. 7 minutes after that, a 4.2 earthquake rattled the residents
of the East Bay. The magnitude 3.2 and 4.2 events are clearly visible on
this image; the 2.5 event is a very low-amplitude squiggle.
- 09/12/94 Double Spring Flat, NV
This M 6.0 earthquake was located on the California-Nevada border, 30 km
southeast of Lake Tahoe. The event was felt over large portions of California
and Nevada, including San Francisco, Sacramento, and Reno. The mainshock
occurred at 12:23 UTC and was followed by several large aftershocks, including
a M 4.2 at 17:14, a M 5.3 at 23:57, and a M 4.4 at 6:15 the following day.
- 04/07/95 Tonga
This Ms 8.0 earthquake was located in the region of Tonga in the
southwest Pacific and occurred at relatively shallow depth (31 km).
The large amplitude, long period (~20 sec) waves on the seismogram,
arriving approximately 20 minutes after the P-wave, are surface waves.
- 07/09/95 Woodside, CA
This "earthquake" was created when one of the largest eucalyptus
trees in the United States toppled over. The tree was 32 feet
around at its base and over 200 feet tall.