Simulations of strong ground motion in SW Iberia for the 1969 February 28 (M_s= 8.0) and the 1755 November 1 (M∼ 8.5) earthquakes – II. Strong ground motion simulations     

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 ( M _s= 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   

花海湖泊古风成砂的粒度特征及其环境意义   总被引：19，自引：5，他引：19  

胡刚  王乃昂  罗建育  高顺尉  李巧玲 《沉积学报》2001,19(4):642-647

通过野外调查和室内分析,发现在花海剖面全新世出现了三次特有的风成砂,并对其原因进行了初步的分析。前两次风沙形成期分别与第一、第二新冰期相对应,而且分析表明第一风沙形成期的冬季风强度要比全新世其它时期强,持续时间长。这为研究本区土地退化、荒漠化等问题提供了自然背景,特别是对西部大开发战略重点之一的生态环境保护与建设具有特殊的意义  相似文献   

Reply to Carcaillet and Vernet     

Katherine J. Willis  Edina Rudner  Pl Sümegi 《Quaternary Research》2001,55(3):388

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The atmospheric electric agitation and its origin     

H. Israël 《Pure and Applied Geophysics》1959,42(1):140-142

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Lehrbuch der bodenkunde: Scheffer,Fritz und Paul Schachtschabel (1970): 7. Aufl. 447 S., 121 Abb., 70 Tab., 1 Farbtafei. Stuttgart: Enke Verlag,DM 56,-     

Pál Stefanovits 《Geoforum》1972,3(3):86

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Remanent magnetism of anorganic and organic substances and its exploitation in treating historical problems     

Václav Bucha  Reviewer J. Anděl 《Studia Geophysica et Geodaetica》1971,15(3-4):353-363

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   

Remarks concerning the “ten-year-period” of atmospheric electricity     

Prof. Dr. Hans Israël 《Meteorology and Atmospheric Physics》1968,17(1):88-89

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Buchbesprechungen     

F. Steinhauser  W. Mörikofer  H. Israël  M. Toperczer 《Meteorology and Atmospheric Physics》1953,6(1):114-128

Ohne Zusammenfassung  相似文献   

Hans Benndorf †     

H. Israël  M. Toperczer 《Meteorology and Atmospheric Physics》1953,6(1):111-113

Ohne Zusammenfassung

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Hans Benndorf

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Multi-wavelength observations of the onset phase of a coronal mass ejection     

Innes  D.E.  Inhester  B.  Srivastava  N.  Brekke  P.  Harrison  R.A.  Matthews  S.A.  Noëns  J.C.  Schmieder  B.  Thompson  B.J. 《Solar physics》1999,186(1-2):337-361

The structure and dynamics of the initial phases of a coronal mass ejection (CME) seen in soft X-ray, extreme ultraviolet and optical emission are described. The event occurred on the SW limb of the Sun in active region AR 8026 on 9 April 1997. Just prior to the CME there was a class C1.5 flare. Images taken with the Extreme Ultraviolet Imaging Telescope (EIT) reveal the emergence of a candle-flame shaped extreme ultraviolet (EUV) cavity at the time of the flare. Yohkoh images, taken about 15 min later, show that this cavity is filled with hot X-ray emitting gas. It is most likely that this is the site of the flare. Almost simultaneous to the flare, an H surge or small filament eruption occurs about 50 arc sec northwards along the limb from the EUV cavity. At both the site of the core of the hot, EUV cavity and the filament ejection are X-ray jets. These jets seem to be connected by hot loops near their bases. Both jets disappear within a few minutes of one another.Clear evidence of the CME first appeared in the Large Angle Spectrometric Coronagraph (LASCO) and EIT images 40 min after the flare and onset of the filament ejection. It seems to come from a region between the two X-ray jets. This leads to the speculation that magnetic field reconnection near one footpoint of a loop system triggers reconnection near its other footpoint. The loop system is destabilized and ultimately gives rise to the CME. This possibility is supported by magnetic field and H images taken when the active region was at disk center which show that the active region had a double bipole structure with dark H filaments between the bipoles.  相似文献