Seismograms of Interest
Here are some of sample seismograms, recorded by the Berkeley Digital Seismic Network (BDSN), using Make Your Own Seismogram. You can view current seismograms at Quicklook tool, which displays waveforms from 9 stations, updated every 10 minutes.
- 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.