共查询到20条相似文献，搜索用时 31 毫秒
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Representations of the radiated energy in earthquakes 总被引：7，自引：0，他引：7
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On tidal triggering of earthquakes at Campi Flegrei, Italy 总被引：2，自引：0，他引：2
Paul A. Rydelek I. Selwyn Sacks Roberto Scarpa 《Geophysical Journal International》1992,109(1):125-135
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Perceptible earthquakes in the United Kingdom 总被引：1，自引：0，他引：1
Paul W. Burton 《Geophysical Journal International》1978,54(2):475-479
Summary. Earthquake occurrence in the United Kingdom is analysed using Gumbel's third type asymptotic distribution of extreme values. Uncertainties in both the parameters and predictions derived from the Gumbel distribution are obtained and it is shown that an earthquake with body-wave magnitude slightly over five is the one most likely to be perceived at any point in the United Kingdom. 相似文献
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Low detection capability of global earthquakes after the occurrence of large earthquakes: investigation of the Harvard CMT catalogue 总被引：4，自引：0，他引：4
Takaki Iwata 《Geophysical Journal International》2008,174(3):849-856
We investigated the detection capability of global earthquakes immediately after the occurrence of a large earthquake. We stacked global earthquake sequences after occurrences of large earthquakes obtained from the Harvard centroid-moment tensor catalogue, and applied a statistical model that represents an observed magnitude–frequency distribution of earthquakes to the stacked sequence. The temporal variation in model parameters, which corresponds to the detection capability of earthquakes, was estimated using a Bayesian approach. We found that the detection capability of global earthquakes is lower than normal for several hours after the occurrence of large earthquakes; for instance, the duration of lowered detection capability of global earthquakes after the occurrence of an earthquake with a magnitude of seven or larger is estimated to be approximately 12 hr. 相似文献
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Two great Mongolian earthquakes, Tsetserleg and Bolnay, occurred on 1905 July 9 and 23. We determined the source history of these events using body waveform inversion. The Tsetserleg rupture (azimuth N60°) correspond to a N60° oriented branch of the long EW oriented Bolnay fault.
Historical seismograms recorded by Wiechert instruments are digitized and corrected for the geometrical deformation due to the recording system. We use predictive filters to recover the signals lost at the minute marks.
The total rupture length for the Tsetserleg earthquake may reach up to 190 km, in order to explain the width of the recorded body waves. This implies adding 60 km to the previously mapped fault. The rupture propagation is mainly eastward. It starts at the southwest of the central subsegment, showing a left lateral strike-slip with a reverse component. The total duration of the modelled source function is 65 s. The seismic moment deduced from the inversion is 1021 N m, giving a magnitude M w = 8 .
The nucleation of the Bolnay earthquake was at the intersection between the main fault (375 km left lateral strike-slip) and the Teregtiin fault (N160°, 80 km long right lateral strike-slip with a vertical component near the main fault). The rupture was bilateral along the main fault: 100 km to the west and 275 km to east. It also propagated 80 km to the southeast along the Teregtiin fault. The source duration was 115 s. The moment magnitude Mw varies between 8.3 and 8.5.
The nucleation and rupture depths remain uncertain. We tested three cases: (1) nucleation and rupture depth limited to the seismogenic zone; (2) nucleation in the seismogenic zone and rupture propagation going to the base of the crust and (3) nucleation within the crust–upper mantle interface and rupture propagation within the upper mantle. 相似文献
Historical seismograms recorded by Wiechert instruments are digitized and corrected for the geometrical deformation due to the recording system. We use predictive filters to recover the signals lost at the minute marks.
The total rupture length for the Tsetserleg earthquake may reach up to 190 km, in order to explain the width of the recorded body waves. This implies adding 60 km to the previously mapped fault. The rupture propagation is mainly eastward. It starts at the southwest of the central subsegment, showing a left lateral strike-slip with a reverse component. The total duration of the modelled source function is 65 s. The seismic moment deduced from the inversion is 10
The nucleation of the Bolnay earthquake was at the intersection between the main fault (375 km left lateral strike-slip) and the Teregtiin fault (N160°, 80 km long right lateral strike-slip with a vertical component near the main fault). The rupture was bilateral along the main fault: 100 km to the west and 275 km to east. It also propagated 80 km to the southeast along the Teregtiin fault. The source duration was 115 s. The moment magnitude Mw varies between 8.3 and 8.5.
The nucleation and rupture depths remain uncertain. We tested three cases: (1) nucleation and rupture depth limited to the seismogenic zone; (2) nucleation in the seismogenic zone and rupture propagation going to the base of the crust and (3) nucleation within the crust–upper mantle interface and rupture propagation within the upper mantle. 相似文献
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We have collected and re-examined macroseismic information for large Central American earthquakes since the beginning of the period of instrumental recording about one hundred years ago, and combined this with a reassessment of early instrumental information to produce a catalogue of 51 events that, we believe includes ail those with magnitudes ( Ms ) greater than 7.0. We have reassessed surface-wave magnitudes by consulting station bulletins and we have derived a correction that gives an equivalent Ms for events of intermediate depth. We have also developed a regional relationship between Ms and seismic moment, which enables us to estimate the seismic slip rate across the Middle American Trench. Our best estimates give an average slip rate several times smaller than suggested convergence rates, but with the seismic slip in the central segment of the trench almost an order of magnitude smaller than that in the segments on either side. The low seismic slip rate may indicate aseismic crustal deformation 相似文献
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Statistical study of the occurrence of shallow earthquakes 总被引：1，自引：0，他引：1
Summary. The time—space-magnitude interaction of shallow earthquakes has been investigated for three catalogues: worldwide ( M ≥ 7.0), Southern and Northern California ( M ≥ 4.0) and Central California ( M ≥ 1.5). The earthquake sequences are considered as a multi-dimensional stochastic point process; the estimates of the parameters for a branching model of the seismic process are obtained by a maximum-likelihood procedure. After applying magnitude—time and magnitude—distance scaling, the pattern of relationship among earthquakes of different magnitude ranges is almost identical. The number of foreshocks diminishes as the magnitude difference between the main shock and the foreshocks increases, while the magnitude distribution of aftershocks has the opposite property. The strongest aftershocks are likely to occur at the beginning of the sequence; later they migrate away with velocities of the order of km/day. The sequences which are composed of smaller aftershocks last longer and there are indications that they remain essentially in the focal region. Foreshocks also appear to migrate, but in this case, toward the main shock. The rate of occurrence of dependent shocks increases as t -1 as the origin time of the main shock is approached, effectively making every earthquake a multi-shock event. This interaction of earthquakes was modelled by a Monte-Carlo simulation technique. The statistical inversion of simulated catalogues was undertaken to derive the information we would be able to retrieve from actual data, as well as possible errors of estimates. The possibility of using these results as a tool for seismic risk prediction is discussed and evaluated. 相似文献
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Deep-crustal earthquakes in the southern Baltic Shield 总被引：1，自引：0，他引：1
Ronald Arvidsson Rutger Wahlström Ota Kulhánek 《Geophysical Journal International》1992,108(3):767-777
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X. Boës S. B. Moran J. King M. N. Cağatay A. Hubert-Ferrari 《Journal of Paleolimnology》2010,43(4):901-920
In 1999, the large surface-rupturing earthquakes of Izmit and Duzce completed a 60-year cycle that included a westward migration
of nine consecutive large earthquake failures (>50 km surface rupture), which started with the 1939 Erzincan earthquake in
eastern Turkey. In this study, we focused on seismic cycles and seismic risk predictability along the North Anatolian Fault
(NAF). Toward the west end of the NAF (26°E–32°E, i.e. Bolu), large earthquake frequency is measured from either historic
earthquake catalogs, or geologic records from isolated outcrops and marine sediment cores from the Marmara Sea. In comparison,
the eastern part of the NAF zone (32°E–42°E) is less well documented by palaeo-seismologic archives. Thus, the sediment records
of lake basins located on the eastern NAF zone constitute a unique opportunity for testing a new palaeo-seismologic approach.
To this end, we used a diverse array of complementary methods involving: (1) a 600-km transect of fault-related lakes, (2)
sedimentologic observations on cores from six lakes, and (3) a comparison between records of catastrophic sediment transfers
in lakes (i.e. radionuclide chronomarkers and erosion tracers) and historic earthquake reports. Our study indicates that lakes
along the NAF are sensitive geologic recorders of large surface-rupturing earthquakes (surface-wave magnitude (M
s) ≥ 6.9); smaller intensities are not recorded. The most responsive lake systems exhibit increases in sediment accumulation
by a factor of >40 for a >3-m strike-slip displacement (M
s ≥ 7). However, based on results from the 1939 Erzincan earthquake (M
s = 7.8) chronostratigraphic marker, large surface-rupturing earthquakes are detected only by certain lake records and not
by others. Matching multiple lake records along the NAF provides information both on the location of a surface rupture of
a paleo-earthquake as well as its magnitude. Finally, the shallow lake basins along the NAF could potentially document cycles
of large seismic events for at least the late Holocene. 相似文献
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Are earthquakes predictable? 总被引：1，自引：0，他引：1
Yan Y. Kagan 《Geophysical Journal International》1997,131(3):505-525
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