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2 results, page 1 of 1

Magnitude determination of Mexican earthquakes

Shri Krishna Singh (1994)

We explore two altemative magnitude scales, MA and ME, for quasi-real time estimate of magnitude of moderate and large Mexican earthquakes using broadband recordings at Ciudad Universitaria (CU), Mexico D.F., Mexico. MA and Me are based on amplitude of band-pass filtered (between 15 and 30 sec) velocity traces and estimate of radiated seismic energy, respectively. Both scales are tied to the moment magnitude, MW. MA is adequate for shallow, moderate, and large earthquakes, but appears to saturate for major and great earthquakes. ME, on the other hand, does not suffer from saturation and should be valid for events of all depths. In as much as MA measures long-period characteristics of an event while the contribution to ME mostly comes from frequencies near the comer frequency of the event, the magnitude on the two scales may differ for the same earthquake, even if MA has not saturated. Since a large disparity in the two magnitudes may be indicative of anomalous nature of an earthquake, we recommend the use of both scales whenever possible.

Article

Magnitude scále Seismic energy Amplitude Escala de magnitud Energía sísmica Amplitud Magnitude scále Seismic energy Amplitude Seismology concept8601 Seismology CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO GEOFÍSICA SISMOLOGÍA Y PROSPECCIÓN SÍSMICA

Magnitude and Epicenter Estimations of Mexican Earthquakes form Isoseismic Maps

Shri Krishna Singh (1980)

Relationships between magnitude, M, and areas, Ai, of modified intensity contours IV, V and VI of the form M = λi log Ai + µi are derived from Mexican earthquakes. Due to insufficient data, λi has been fixed to 1. Events have been grouped broadly as interplate and intraplate events. Within the range of their validity (7.0≤ M ≤8.2 for interplate; 6.4 ≤ M ≤ 7.1 for intraplate) the relations would give estimate of M to within ± 0.3 to ± 0.4 unit ( one standard deviation) of magnitude. The attenuation of intensity for interplate earthquakes is higher than that for intraplate earthquakes. The attenuation for interplate earthquakes is comparable to or greater than for Southern California earthquakes. Epicenters estimated at the center of maximum intensity contours differ from instrumental epicenter bye 48 ± 22 km.

Article

Magnitude Epicenter Mexican Earthquakes Isoseismic Maps Magnitude Epicenter Mexican Earthquakes Isoseismic Maps concept8601 Seismology CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO GEOFÍSICA SISMOLOGÍA Y PROSPECCIÓN SÍSMICA