The magnitude 9.2 Great Alaska Earthquake that struck south-central at 5:36 p.m. on Friday, March 27, 1964, is the largest recorded earthquake in U.S. history and second-largest with modern instruments. was felt throughout most of mainland Alaska, as far west Dutch Harbor Aleutian Islands some 480 miles away, Seattle, Washington, more than 1,200 to southeast fault rupture, where Space Needle swayed perceptibly. caused rivers, lakes, other waterways slosh away coasts Texas Louisiana....

Measurements of ground motion taken near large underground explosions, when they are compared with teleseismic recordings the same event, allow a direct estimation earth's short-period attenuation. Spectra from measurements made within 15 km explosion Boxcar in Nevada those computed Norway at Δ ≃ 72°. The effective quality parameter QE is estimated over band 0.6–3.0 Hz. From three near-source stations, found to range between 1400 and 2300 mean value 1700. time-domain calculations comparable...

Abstract The spectra of the Love waves from five earthquakes 1966 Parkfield sequence, recorded at Berkeley, have been studied for evidence source propagation. Independent field suggests that main shock sequence may propagated on a line away Berkeley. modulation effect propagation amplitude spectrum is discussed. This dependent upon total time delay due to rupture down fault and seismic wave back point initial rupture, thus ambiguous with respect velocity length. Consideration frequency phase...

Research Article| November 09, 2016 Origins of a National Seismic System in the United States John R. Filson; Filson aEarthquake Hazards Program, U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, Virginia 20192 U.S.A.jfilson@usgs.gov Search for other works by this author on: GSW Google Scholar Walter J. Arabasz bDepartment Geology and Geophysics, University Utah, 115 South 1460 East, Salt Lake City, Utah 84112 U.S.A.arabasz@seis.utah.edu Author Article Information Publisher:...

Research Article| January 01, 2001 The Advanced National Seismic System Harley Benz; Benz U. S. Geological Survey MS 966, Box 25046 DFC Denver, CO 80225 (H.B., R.B., A.F., K.S.) benz@usgs.gov buland@usgs.gov afrankel@usgs.gov shedlock@usgs.gov Search for other works by this author on: GSW Google Scholar Ray Buland; Buland John Filson; Filson U.S. 905 Center Reston, VA 20192 jfilson@usgs.gov (J.F.) Arthur Frankel; Frankel Kaye Shedlock Seismological Letters (2001) 72 (1): 70–75....

Carbonatites are igneous rocks formed in the crust by fractional crystallization of carbonate-rich parental melts that mostly mantle derived. They dominantly consist carbonate minerals such as calcite, dolomite, and ankerite, well minor ...Read More

Abstract An observational study of S from near earthquakes in western central California has been conducted. The average velocity a single direct arrival at Berkeley (BRK) 25 within 108 km is 3.60 ± .05 km/sec. At Vineyard (VIN) the clearest 12 97 3.00 .06 A weaker, earlier observed VIN for 50 < Δ 100 indicating 3.51 two arrivals may be due to either lateral or vertical rustal contrast. greater attenuation higher with respect BRK indicate dimension an anelastic zone associated...

The P - and S -wave arrivals from local earthquakes were studied using an array of 10 three-component instruments in around a tunnel at Garni Observatory, Armenia. has three-dimensional configuration with lateral dimensions 300 to 500 m depth extent 100 m. Estimates the horizontal vertical components slowness for wave fronts used determine angles approach propagation velocity. results showed that region low average velocities both (1.43 km/sec) (0.61 waves, so steep incidence. Waveforms one...

The Advanced National Seismic System (ANSS),an initiative begun in 1998 to integrate, expand, and modernize seismic monitoring nationwide, is providing improvements earthquake the development, production, delivery of data, information, science. ANSS an element Earthquake Hazard Program (EHP) U.S.Geological Survey (USGS). USGS Information Center (NEIC),an integral part ANSS, has incorporated into its routine operations many developments data processing products supported by ANSS. four...

A study has been made of the capability Norwegian Seismic Array to discriminate between earthquakes and underground explosions occurring in central Asia western Russia. The ratio surface body wave magnitudes (Ms: mb) used exclusively, chief application array being detection measurement low amplitude waves. Beamforming matched filtering were signal enhancement techniques applied. Of 34 events studied, 10 identified as explosions, 22 earthquakes, two unidentifiable because high, long period...

A little more than 50 years ago, on 27 March 1964, the Great Alaska earthquake and tsunami struck. At moment magnitude 9.2, this is notable as largest in U.S. written history second‐largest ever recorded by instruments worldwide. But what resonates today are its impacts understanding of plate tectonics, generation, well development national programs to reduce risk from earthquakes tsunamis.

abstract The Kolomogorov model of event occurrence as developed by Knopoff in earthquake studies has been applied to a volcanic swarm. It is shown that this case, where the rate seismic energy release was nearly constant time, adequately relates various seismicity statistics