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1.
Geo-Characterization at selected accelerometric stations in Crete (Greece) and comparison of earthquake data recordings with EC8 elastic spectra 总被引：1，自引：0，他引：1
A. Savvaidis B. Margaris N. Theodoulidis V. Lekidis Ch. Karakostas C. Loupasakis D. Rozos P. Soupios M. -D. Mangriotis U. Dikmen Par. Tsangaratos E. Kokinou A. Vafidis Th. Rondoyanni I. Kalogeras S. Koutrakis A. Sarris N. Papadopoulos 《Central European Journal of Geosciences》2014,6(1):88-103
To estimate the seismic response according to Eurocode (EC8) and almost all other national codes, site conditions have to be properly characterized so that soil amplification and the corresponding peak ground motion can be calculated. In this work, different geophysical and geotechnical methods are combined in order to define the detailed ground conditions in selected sites of the Hellenic Accelerometric Network (HAN) in Crete. For this purpose, the geological information of the sites and shear wave velocity, calculated from surface wave measurements, is used. Additionally, ground acceleration data recorded through HAN have been utilized from intermediate depth earthquakes in the broader area of South Aegean Sea. Using the recorded ground motion data and the procedure defined in EC8, the corresponding elastic response spectrum is calculated for the selected sites. The resulting information is compared to the values defined in the corresponding EC8 spectrum for the seismic zone that includes the island of Crete. The comparison shows that accurate definition of ground type through geological, geotechnical and geophysical investigations is important. However, our current comparison focuses on the distribution of values rather than the absolute values of EC8-prescribed spectra, and the results should be considered in this context. 相似文献
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Palaeoseismological and archaeological analysis of a trench enabled us to estimate the Holocene slip rates on the East Helike Fault, flanking the south-western Gulf of Corinth. We recognized two major fault strands within the trench: the ‘north fault’ controls a succession of three colluvial wedges and the deposition of a 2.7 m thick sedimentary sequence. The ‘south fault’ controls the deposition of a 2.9-m thick brownish-red colluvium. Based on colluvial stratigraphy, radiocarbon dating of the sediments suggests that the slip rate was c. 0.3 mm yr−1 from 10 250 to c. 1400 bp , when it increased dramatically to c. 2.0 mm yr−1 after a strong earthquake event near 1400 bp . The faster slip rate evidently increased the sedimentation rate. 相似文献
3.
Heinrich Hora George H. Miley Xiaoling Yang Paraskevas Lalousis 《Astrophysics and Space Science》2011,336(1):225-228
An extreme anomaly of laser-plasma interaction with petawatt-picosecond (PW-ps) pulses of very high contrast ratio for suppression
of relativistic self-focusing permitted a come-back of the Bobin-Chu side-on ignition of uncompressed deuterium-tritium (DT)
fusion fuel. The plasma blocks for the side-on ignition have to be produced by the well confirmed nonlinear force acceleration
which is about 100,000 times higher than thermo-kinetic fluid-dynamic acceleration for comparison with astrophysical cases.
It is essential that the dielectric plasma properties within the nonlinear force are used. Using the measured ion beam densities
above 1011 A s/cm2 the ignition mechanism needed numerical and theoretical studies of extremely strong shock phenomena. When extending these
results to the side-on ignition of uncompressed hydrogen-boron11 (HB11), surprisingly, the ignition by this shock mechanism
was only about 10 times more difficult than for DT in contrast to ignition by spherical laser driven compression using thermo-kinetic
conditions in which case HB11 ignition is 100,000 times more difficult than DT. 相似文献
4.
Ilia Ioanna Rozos Dimitrios Perraki Theodora Tsangaratos Paris 《Central European Journal of Geosciences》2009,1(4):431-442
Thirty bulk samples of hard soils-soft rocks such as marls, originating from Euboea Island and Peloponnesus area, were investigated to evaluate their geotechnical behavior. Specifically, by conducting a series of physical and geotechnical tests, such as liquid limit and plastic limit tests, along with the estimation of the grain size fraction, Slake Durability and Point Load Test. Certain parameters were determined and used for empirical correlations with their mineralogical characteristics. The mineralogical composition was determined by X-ray diffraction, thermo-gravimetric and thermal analysis, succeeded by textural analysis performed by Optical Microscope. With the help of the above mentioned tests, we interpreted the observed geotechnical behavior of the examined weak rocks by means of mineralogical composition and texture. Durability and the unconfined compressive strength was found to be influenced by high percentages in carbonate minerals. In addition, it was found that a decrease in clay content resulted in higher strength and durability values. The concluded empirical correlations verified the influence of these parameters and gave a general overview of the engineering behavior of the examined weak rocks. 相似文献
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The quick response of civil authorities after a major disaster event in an urban area is essential for the reduction of damages
and impacts to human lives. One of the first critical problems to be solved at the very early stages of response is the optimum
management of emergency vehicles and real time knowledge of the accessibility of the road network. In this article the concept
of using a number of emergency vehicles as sensors for monitoring the traffic conditions in an urban area after a major disaster
event is described. The fleet management system used for this taks is working with ral time DGPS. The system makes use of
existing vehicle fleets in the urban area, rapidly collecting data and covering the whole road network. It records travel
times with the help of the GPS system for every road segment driven through by each vehicle sensor, thus providing a digital
time database from which traffic parameters can be also computed. It can be used for real time monitoring of traffic conditions
under disaster or emergency situations where all the previously available data become invalid or unreliable. ? 2002 Wiley
Periodicals, Inc. 相似文献
8.
Ioanna Ilia Dimitrios Rozos Theodora Perraki Paris Tsangaratos 《Central European Journal of Geosciences》2012,4(4):663-663
The original version of this article was published in Central European Journal of Geosciences volume 1, issue 4 (2009), pp 431–442, DOI:10.2478/v10085-009-0029-0. Unfortunately the original version of this article contains mistakes in authors names which we correct here. Editorial staff of the journal apologise for any inconvenience that may result from the oversight. 相似文献
9.
G.‐Akis Tselentis Paraskevas Paraskevopoulos Nikos Martakis 《Geophysical Prospecting》2010,58(5):845-859
We determine the attenuation structure of a three‐dimensional medium based on first pulse‐width measurements from microearthquake data. Ninety‐five microearthquakes from a seventy stations local network were considered in this study. Measurements of the first half cycle of the wave, the so‐called rise time τ were carried out on high quality velocity seismograms and inverted to estimate the P‐waves intrinsic quality factor Qp. The results of this investigation indicate that first pulse width data from a local microearthquake network permit retrieval with sufficient accuracy of the heterogeneous Qp structure. The inferred attenuation variability corresponds to the known geological formations in the region. 相似文献
10.
Retroward extrusion of high‐pressure rocks: An example from the Hellenides (Pelion Blueschist Nappe,NW Aegean) 
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下载免费PDF全文 Current tectonic models interpret the Hellenides as a unidirectional, SW‐vergent orogenic belt. New (micro‐)structural and amphibole chemistry analyses show, instead, that the exhumation of the Pelion Blueschist Nappe (PBN) of the Internal Hellenides was achieved by retroward (ENE)‐directed ductile extrusion, which opposes the principal (proward) orogenic vergence. Retroward extrusion occurred between two sub‐parallel, major ductile shear zones (Basal thrust and Upper detachment) with opposite shear senses, which operated simultaneously under blueschist‐ to greenschist‐facies conditions during the late Eocene–Oligocene. Because the PBN is tectonically sandwiched between Pelagonian basement rocks, we suggest that the PBN protolith was accumulated during the Late Cretaceous in an incipient backarc basin developed above the NE‐dipping subduction of the Pindos Ocean beneath the Pelagonian microcontinent. Subsequent Apulian–Pelagonian collision triggered basin inversion and the proward‐dipping intracontinental subduction that caused the early/middle Eocene blueschist‐facies metamorphism followed by the retroward extrusion of the PBN. 相似文献