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51.
Raphaël Grandin José Fernando Borges Mourad Bezzeghoud Bento Caldeira Fernando Carrilho 《Geophysical Journal International》2007,171(2):807-822
This is the second paper of a series of two concerning strong ground motion in SW Iberia due to earthquakes originating from the adjacent Atlantic area. The aim of this paper is to use the velocity model that was proposed and validated in the companion paper for seismic intensity modelling of the 1969 ( M s = 8.0) and 1755 ( M = 8.5–8.7) earthquakes.
First, we propose a regression to convert simulated values of Peak Ground Velocity (PGV) into Modified Mercalli Intensity (MMI) in SW Iberia, and using this regression, we build synthetic isoseismal maps for a large ( Ms = 8.0) earthquake that occurred in 1969. Based on information on the seismic source provided by various authors, we show that the velocity model effectively reproduces macroseismic observations in the whole region. We also confirm that seismic intensity distribution is very sensitive to a small number of source parameters: rupture directivity, fault strike and fault dimensions. Then, we extrapolate the method to the case of the great ( M = 8.5–8.7) 1755 earthquake, for a series of hypotheses recently proposed by three authors about the location of the epicentral region. The model involving a subduction-related rupture in the Gulf of Cádiz results in excessive ground motion in northern Morocco, suggesting that the source of the 1755 earthquake should be located further west. A rupture along the western coast of Portugal, compatible with an activation of the passive western Iberian margin, would imply a relatively low average slip, which, alone, would could not account for the large tsunami observed in the whole northern Atlantic ocean. A seismic source located below the Gorringe Bank seems the most likely since it is more efficient in reproducing the distribution of high intensities in SW Iberia due to the 1755 earthquake. 相似文献
First, we propose a regression to convert simulated values of Peak Ground Velocity (PGV) into Modified Mercalli Intensity (MMI) in SW Iberia, and using this regression, we build synthetic isoseismal maps for a large ( M
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Summary Properties of the thermoremanent magnetization of various archaeological materials (baked-clay objects, samples from old trees, bones and stones) were investigated with the purpose to assess the possibility of their use for the determination of the earth's magnetic field in the historical past and to apply the data for solving some practical problems. It turns out that most of those materials yield magnetic values that can be used for making the radiocarbon dating method more accurate, for determining the degree of burning and for direct archaeomagnetic dating. The new conclusions also contribute to the knowledge of changes in the earth's magnetic field in the past. 相似文献
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F. Steinhauser W. Mörikofer H. Israël M. Toperczer 《Meteorology and Atmospheric Physics》1953,6(1):114-128
Ohne Zusammenfassung 相似文献
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