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 A
complex magnitude 6.5 earthquake recorded on June 15, 1999 in Central Mexico.
This seismogram was recorded at the GSN site ANMO at an epicentral distance
of 18.3 degrees. The earthquake consisted of at least two events about 4
seconds apart.
(Tyler Storm, ASL) |
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| Two Banda Sea earthquakes recorded on November 9, 1998 in Kamchatka. The data were recorded with an excellent signal-to-noise ratio on PASSCAL instruments during the Site Edge of Kamchatka Slab experiment by station APA 100 km southwest of Petropavlovsk. A large, magnitude 6.8 event was followed 8.5 minutes later by a nearby magnitude 7.0 event. With epicentral distances of 60 degrees for both events, the time difference between their occurrence is almost identical with their corresponding S-P times, resulting in critical interference between the S wave arrival of the first event and the P wave arrival of the second event. (Jonathan Lees, Yale University) |
A 566km deep, magnitude 6.4 earthquake, recorded in eastern Russia on April 8, 1999. At 164 degrees, GSN station PLCA recorded several strong core and depth phases, including PKPdf, PKPab, pPKPab and PP. (Tyler Storm, ASL) |
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| A typical mining explosion recorded on a vertical component PEPP instrument at Eastern Greene Community School in rural Greene county, in southern Indiana, PPEGH. The seismogram, filtered with a 1Hz highpass filter, shows: a high frequency, commonly emergent P arrival, a low frequency S phase that is often more impulsive than the P phase, and a prominent, high frequency Rayleigh wave with normal dispersion. (Gary Pavlis,Indiana University) |
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"Earthquakes" created by members of Congress and their staff during a reception of the National Science Funding Coalition on Capitol Hill in May of this year. Groundmotion was recorded by an AS-1 seismometer that was connected via an amplifier to a helicorder. Visitors signed the signals they created. (IRIS) |
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