排序方式： 共有22条查询结果，搜索用时 31 毫秒
1.
2.
Estimating coseismic deformations from near source strong motion records: methods and case studies 总被引：6，自引：5，他引：1
Digital strong-motion accelerographs have opened up the possibility of extracting ground motion characteristics at much lower frequencies than was offered by analogue instruments. High-quality digital data obtained close to the faults have tempted several efforts to retrieve permanent ground displacements after an earthquake. Such attempts have been partly successful, and somewhat subjective, the main reason being the presence of baseline offsets in the accelerometric data. We review existing methods for such applications, discuss their limitations and propose a more objective and improved scheme to make baseline adjustments and obtain permanent displacements. The proposed technique is applied to 26 digital recordings from the 29 May 2008 Ölfus Earthquake in South Iceland and 9 recordings from the 1999 Chi-Chi, Taiwan, Earthquake, and the permanent displacements obtained are compared with published results and GPS measurements from nearby stations. Our case studies show that the proposed technique, in addition to being simple and objective, is effective in making adjustments for baseline errors in accelerometric data. 相似文献
3.
Vera D’Amico Dario Albarello Ragnar Sigbjörnsson Rajesh Rupakhety 《Bulletin of Earthquake Engineering》2016,14(7):1797-1811
We present the results of probabilistic seismic hazard assessment for Iceland in the framework of the EU project UPStrat-MAFA using the so-called site approach implemented in the SASHA computational code. This approach estimates seismic hazard in terms of macroseismic intensity by basically relying on local information about documented effects of past seismic events in the framework of a formally coherent and complete treatment of intensity data. In the case of Iceland, due to the lack of observed intensities for past earthquakes, local seismic histories were built using indirect macroseismic estimates deduced from epicentral information through an empirical attenuation relationship in probabilistic form. Seismic hazard was computed for four exceedance probabilities for an exposure time of 50 years, equivalent to average return periods of 50, 200, 475 and 975 years. For some localities, further return periods were examined and deaggregation analysis was performed. Results appear significantly different from previous seismic hazard maps, though just a semi-qualitative comparison is possible because of the different shaking measure considered (peak ground acceleration versus intensity), and the different computational methodology and input data used in these studies. 相似文献
4.
R. Sigbjörnsson J. Th. Snæbjörnsson S. M. Higgins B. Halldórsson S. Ólafsson 《Bulletin of Earthquake Engineering》2009,7(1):113-126
This preliminary study aims to investigate a M
w
6.3 earthquake that occurred in South Iceland on Thursday 29 May 2008 at 15:45 UTC. The epicentre was in the Olfus District
between the towns of Selfoss and Hveragerdi. This study examines the data recorded and the damage observed immediately after
the event. Horizontal accelerations of up to 80%g were recorded in the epicentral region and there is visual evidence that
the vertical acceleration exceeded 1 g. The PGA data is compared to a ground motion estimation model developed for the South
Iceland earthquakes in June 2000. In general the basic properties of this event are found to be similar to the characteristics
of the South Iceland earthquakes in June 2000. The duration of strong-motion is short and the intensity attenuates rapidly
with increasing distance. The earthquake action resisted by buildings in the near fault area is inspected through evaluation
of elastic as well as inelastic response spectra. The vast majority of structures seemed to withstand the strong-motion fairly
competently and without significant visual damage due firstly to the low-rise, predominantly reinforced concrete or timber,
style of buildings. Secondly, the short duration of strong-motion contributed to the endurance of structures. 相似文献
5.
Macroseismic effects related to strong ground motion: a study of the South Iceland earthquakes in June 2000 总被引：1，自引：1，他引：1
R. Sigbjörnsson S. Ólafsson J. Th. Snæbjörnsson 《Bulletin of Earthquake Engineering》2007,5(4):591-608
The impact of the June 2000 South Iceland earthquakes has been assessed applying data collected in field surveys and strong-motion
recordings from the Icelandic Strong-Motion Network. The areas within approximately 20 km of the causative faults suffered
considerable damage, including transportation and utility systems as well as buildings, both with regard to structure and
inventories. Ground subsidence and dislocations were significant in the near-fault zone. Aftershocks and permanent displacements
of building foundations resulted in progressive structural damage. By introducing holistic measures derived from the acceleration
data, a fair correlation was achieved between the obtained earthquake intensities and the recorded accelerations. The measures
adopted were square root of the sum of the squares (SRSS) values of peak ground acceleration (PGA) and the trace of the Arias
intensity tensor. It was found that the overall attenuation tended to be more rapid than reflected by common strong-motion
models reported in the literature. There is no simple explanation for this behaviour but it is reasonable to suggest that
it can be partly attributed to the heterogeneous and fractured crust that is characteristic of Icelandic geology. 相似文献
6.
Probabilistic seismic hazard assessment for Thailand 总被引：3，自引：1，他引：2
Teraphan Ornthammarath Pennung Warnitchai Kawin Worakanchana Saeed Zaman Ragnar Sigbj?rnsson Carlo Giovanni Lai 《Bulletin of Earthquake Engineering》2011,9(2):367-394
A set of probabilistic seismic hazard maps for Thailand has been derived using procedures developed for the latest US National
Seismic Hazard Maps. In contrast to earlier hazard maps for this region, which are mostly computed using seismic source zone
delineations, the presented maps are based on the combination of smoothed gridded seismicity, crustal-fault, and subduction
source models. Thailand’s composite earthquake catalogue is revisited and expanded, covering a study area limited by 0°–30°N
Latitude and 88°–110°E Longitude and the instrumental period from 1912 to 2007. The long-term slip rates and estimates of
earthquake size from paleoseismological studies are incorporated through a crustal fault source model. Furthermore, the subduction
source model is used to model the megathrust Sunda subduction zones, with variable characteristics along the strike of the
faults. Epistemic uncertainty is taken into consideration by the logic tree framework incorporating basic quantities, such
as different source modelling, maximum cut-off magnitudes and ground motion prediction equations. The ground motion hazard
map is presented over a 10 km grid in terms of peak ground acceleration and spectral acceleration at 0.2, 1.0, and 2.0 undamped
natural periods and a 5% critical damping ratio for 10 and 2% probabilities of exceedance in 50 years. The presented maps
give expected ground motions that are based on more extensive data sources than applied in the development of previous maps.
The main findings are that northern and western Thailand are subjected to the highest hazard. The largest contributors to
short- and long-period ground motion hazard in the Bangkok region are from the nearby active faults and Sunda subduction zones,
respectively. 相似文献
7.
8.
9.
Ground-motion prediction equations (GMPEs) for inelastic response and structural behaviour factors 总被引：1，自引：1，他引：0
The objective of this paper is to present ground-motion prediction equations describing constant-ductility inelastic spectral
ordinates and structural behaviour factors. These equations are intended for application within the framework of Eurocode
8. Most of the strong-motion data used in the present work is obtained from the ISESD (Internet Site for European Strong-motion
Data) databank. Present analysis includes ground motion records from significant Icelandic earthquakes, which are augmented
by records obtained from continental Europe and the Middle East. In all cases the selected ground motion records are generated
during shallow earthquakes within a distance of 100 km from the recording station. The classification of site conditions in
the present work is based on the Eurocode 8 definition. 相似文献
10.
Rotation-invariant mean duration of strong ground motion 总被引：1，自引：1，他引：0
Strong-motion duration is usually computed separately for three components of recorded ground-motion time series. This results in different values of duration for the three components. Furthermore, the computed duration values are dependent on the sensor orientation. Physically, such dependence is not desirable. In this work, computing duration based on resultant recorded motion instead of individual components is proposed. Such a measure of duration is shown to be rotation-invariant and hence independent of the sensor axes. Furthermore, it is demonstrated that the duration of resultant motion represents the mean duration for all possible arbitrary sensor orientations in three-dimensional space. The results indicate that the apparent difference between duration of horizontal and vertical motion reported in the literature is not universal to all definitions of duration. A set of 462 three-component accelerograms from Europe and the Middle East is used to demonstrate and support the presented findings and arguments. 相似文献