scholarly journals Ground motion and macroseismic intensities of a seismic event related to geothermal reservoir stimulation below the city of Basel���observations and modelling

2009 ◽  
Vol 179 (3) ◽  
pp. 1757-1771 ◽  
Author(s):  
Johannes Ripperger ◽  
Philipp K��stli ◽  
Donat F��h ◽  
Domenico Giardini
1997 ◽  
Vol 87 (2) ◽  
pp. 356-369
Author(s):  
Takumi Toshinawa ◽  
J. John Taber ◽  
John B. Berrill

Abstract The areal distribution of seismic ground-motion intensity in the city of Christchurch, New Zealand, during the 1994 Arthurs Pass Earthquake (ML 6.6) was evaluated using an intensity questionnaire together with local site amplifications inferred from seismic recordings and microtremors. In order to estimate the intensity in parts of the city where no intensity data were available, intensity data were compared to relative levels of shaking determined from both weak-motion and microtremor recordings. Weak ground-motion amplification factors were determined using ratios of ground accelerations at five sediment sites with respect to a rock site. Microtremor amplification factors were determined from horizontal-to-vertical spectral ratios at a 1-km spacing throughout the city. A positive correlation between weak-motion and microtremor amplification factors allowed extrapolation of microtremor amplification to estimated MM intensity (EMMI). EMMI ranged from 3 to 6 and was consistent with the questionnaire intensity and geological conditions and showed detailed information on the areal distribution of ground-motion intensity in the city.


2005 ◽  
Vol 21 (1_suppl) ◽  
pp. 165-179 ◽  
Author(s):  
Mehdi Zaré ◽  
Hossein Hamzehloo

The Bam earthquake of 26 December 2003 ( Mw 6.5) occurred at 01:56:56 (GMT, 05:26:56 local time) near the city of Bam in the southeast of Iran. Two strong phases of energy are seen on the accelerograms. The first comprises a starting subevent with right-lateral strike-slip mechanism located south of Bam. The mechanism of the second subevent was a reverse mechanism.


2017 ◽  
Vol 50 (3) ◽  
pp. 1389
Author(s):  
P.M. Paradisopoulou ◽  
E.E. Papadimitriou ◽  
J. Mirek

Stress triggering must be incorporated into quantitative earthquake probability estimate, given that faults are interacted though their stress field. Using time dependent probability estimates this work aims at the evaluation of the occurrence probability of anticipated earthquakes near the city of Thessaloniki, an urban center of 1 million people located in northern Greece, conditional to the time elapsed since the last stronger event on each fault segment of the study area. A method that calculates the macroseismic epicenter and magnitude according to macroseismic intensities is used to improve the existing earthquake catalog (from AD 1600 - 2013 with M≥6.0) in order to compute new interevent and elapsed time values which form the basis for time-dependent probability estimates. To investigate the effects of stress transfer to seismic hazard, the probabilistic calculations presented here employ detailed models of coseismic stress associated with the 20 June 1978 M=6.5 Thessaloniki which is the latest destructive earthquake in the area in the instrumental era. The combined 2015-2045 regional Poisson probability of M≥6.0 earthquakes is ~35% the regional time-dependent probability varies from 0% to 15% and incorporation of stress transfer from 0% to 20% for each fault segment.


Author(s):  
Dimcho Solakov ◽  
Stela Simeonova ◽  
Plamena Raykova ◽  
Boyko Rangelov ◽  
Constantin Ionescu

2020 ◽  
Author(s):  
Marco Mancini ◽  
Iolanda Gaudiosi ◽  
Redi Muci ◽  
Maurizio Simionato ◽  
Klodian Skrame

<p>The city of Durrës was recentely struck by a Mw 6.2 mainshock event (http://cnt.rm.ingv.it/event/23487611) that caused considerable damage and 51 victims. The city is located on an actively seismotectonic belt where seismic catalogues report few past events with magnitude higher than 6.</p><p>Surface geology is generally considered to influence the ground motion recorded on site. The analysis of the influence of local effects on seismic response at ground surface appears relevant also considering that Durrës is a densely populated city prone to high seismic risk and is characterized by several important archeological and cultural heritage sites.</p><p>Preliminary results obtained from recent geophysical in-situ measurements and geological surveys, carried out in Durrës after the ML 5.4, 21<sup>st</sup> September 2019 event, are presented with the aim of providing new elements for the assessment of local seismic hazard and following a comprehensive approach to the modifications induced by the site.</p><p>Twenty-nine single-station noise measurements, processed through the HVSR technique, two MASW surveys and two 2D array measurements were performed. Results from noise measurements define a zone eastward of the historical centre, where the characteristics of surficial soil layers are responsible for modification to the seismic demand. In particular, HVSR curves in this area show amplification higher than 4 at a period higher than 1s. Moreover, on this location a surface waves-velocity profile obtained from a joint inversion of Rayleigh curves from MASW and 2D array with ellipticity individuates a class D soil, EC8 sensu, corresponding to marshy soil of very poor geotechnical quality. These data may be considered as key elements in the site-specific response analyses, i.e. realized according to the international codes (EC8, NEHRP), which allow to quantify the expected ground motion. These results are potentially useful for  correlating  construction typologies and period vibration of the buildings with the site amplification.</p><p>In addition, a damage survey was carried out in one of the most damaged zones after the 21<sup>st</sup> September 2019 earthquake. Because of the following stronger event of the 26<sup>th</sup> November 2019, we think that these preliminary results may provide useful information for the post-earthquake reconstruction and enhancement of the urban resilience.</p><p>                The activities are carried out wihin the framework of the CNR/MOES Joint research project “Seismic risk assessment in cultural heritage cities of Albania” in the biennium 2018-2019 (https://www.cnr.it/en/bilateral-agreements/agreement/60/moes-ministry-of-education-and-sport-of-the-republic-of-albania).</p>


2017 ◽  
Vol 50 (3) ◽  
pp. 1495
Author(s):  
D. Kazantzidou-Firtinidou ◽  
I. Kassaras ◽  
A. Ganas ◽  
C. Tsimi ◽  
N. Sakellariou ◽  
...  

Damage scenarios are necessary tools for stakeholders, in order to prepare protection strategies and a total emergency post-earthquake plan. To this aim, four seismic hazard models were developed for the city of Kalamata, according to stochastic simulation of the ground motion, using site amplification functions derived from ambient noise HVSR measurements. The structural vulnerability of the city was assessed following an empirical macroseismic model, developed for the European urban environment (EMS-98). The impact of the vulnerability due to the seismic hazard potential is also investigated by means of synthetic response spectral ratios at 108 sites of the city. The expected damage grade per building block, is calculated by combining vulnerability with the respective seismic intensities, derived for the four seismic sources. The importance of the followed methodology for implementing microzonation studies is emphasized, since the expected influence of the ground motion amplification due to local soil conditions has been approximated in detail. Moreover, new fragility curves for the main structural types in Kalamata are proposed for each seismic scenario.


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