http://sec.gsfc.nasa.gov/popscise.jpgLa Seismological Society of America se reune en abril de este año, en Santa Fe, New Mexico, y este es uno de los abstractos presentados:
Session: Complexity, Statistics, and Physics of Seismicity and EarthquakesSchedule: Wed 16 Apr - AMLocation: Anasazi Room in the Eldorado Presentation Type: Poster Presenter: Shirley, James
STRONG SUNSPOT CYCLE CORRELATION OF LARGE SHALLOW EARTHQUAKES
SHIRLEY,J.H., Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, jshirley@jpl.nasa.gov.
An updated list of instrumentally recorded large shallow earthquakes (Mw >= 7.5) has been assembled from standard sources. This compilation is based on the catalog of Pacheco & Sykes (BSSA 82, 1306, 1989) for the years 1900-1975, and on the Harvard CMT catalog for the years 1976-2007. The list includes 80 great earthquakes (arbitrarily defined here to be events with seismic moment>=10e21 Nm or Mw >= 7.93). Annual and decadal totals of event frequency and seismic moment for earthquakes with Ms >= 7.0 have also been compiled to provide context and allow comparisons. To exclude foreshocks, aftershocks, and related events, the catalog was declustered such that each retained event represents the largest recorded earthquake within a time window of +/- 2 yr and within a spatial area of radius 1000 km. This resulted in the removal from the sample of 8 (of 76) earthquakes with Mw >= 8.0, and of 63 (of 300) earthquakes with Mw >= 7.5. In the first phase of this study, we found that the distribution of great earthquake occurrence times with respect to the 11-yr solar sunspot cycle is strongly nonrandom (Pr = .005). A bimodal distribution of solar cycle phases is found, with increased event frequency found for the years approaching sunspot minima, and with a second population found associated with sunspot maxima. In the second phase of this study, we evaluated successively larger samples, with threshold magnitudes Mw of 7.9 (n=92), 7.8 (n=122), 7.7 (n=180), 7.6 (n=194), and 7.5 (n=237). The solar cycle correlation found for the largest earthquakes persists in all of these samples (although Pr drops to .05 for the largest set). We will discuss four possible interpretations. This work was supported by the private resources of the author.
This abstract appears in Seismological Research Letters Volume 79, No. 2 on page 293.
Session: Complexity, Statistics, and Physics of Seismicity and EarthquakesSchedule: Wed 16 Apr - AMLocation: Anasazi Room in the Eldorado Presentation Type: Poster Presenter: Shirley, James
STRONG SUNSPOT CYCLE CORRELATION OF LARGE SHALLOW EARTHQUAKES
SHIRLEY,J.H., Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, jshirley@jpl.nasa.gov.
An updated list of instrumentally recorded large shallow earthquakes (Mw >= 7.5) has been assembled from standard sources. This compilation is based on the catalog of Pacheco & Sykes (BSSA 82, 1306, 1989) for the years 1900-1975, and on the Harvard CMT catalog for the years 1976-2007. The list includes 80 great earthquakes (arbitrarily defined here to be events with seismic moment>=10e21 Nm or Mw >= 7.93). Annual and decadal totals of event frequency and seismic moment for earthquakes with Ms >= 7.0 have also been compiled to provide context and allow comparisons. To exclude foreshocks, aftershocks, and related events, the catalog was declustered such that each retained event represents the largest recorded earthquake within a time window of +/- 2 yr and within a spatial area of radius 1000 km. This resulted in the removal from the sample of 8 (of 76) earthquakes with Mw >= 8.0, and of 63 (of 300) earthquakes with Mw >= 7.5. In the first phase of this study, we found that the distribution of great earthquake occurrence times with respect to the 11-yr solar sunspot cycle is strongly nonrandom (Pr = .005). A bimodal distribution of solar cycle phases is found, with increased event frequency found for the years approaching sunspot minima, and with a second population found associated with sunspot maxima. In the second phase of this study, we evaluated successively larger samples, with threshold magnitudes Mw of 7.9 (n=92), 7.8 (n=122), 7.7 (n=180), 7.6 (n=194), and 7.5 (n=237). The solar cycle correlation found for the largest earthquakes persists in all of these samples (although Pr drops to .05 for the largest set). We will discuss four possible interpretations. This work was supported by the private resources of the author.
This abstract appears in Seismological Research Letters Volume 79, No. 2 on page 293.
Se debe recordar la enorme cantidad de partes de atomos que vienen del sol, de los cuales nos protege el campo magnético de la tierra. Es precisamente en los equinoccios (comienzos de primavera y comienzo de otoño) cuando están mejor alineados el campo magnético de la tierra y el viento solar y las auroras boreales son vistas en su mayor magnitud. Las erupciones de lava salen a la superficie en franjas , con cargas magnéticas definidas según Wikipedia.
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