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| Titel |
Estimation of seismic ground motions using deterministic approach for major cities of Gujarat |
| VerfasserIn |
J. Shukla, D. Choudhury |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 12, no. 6 ; Nr. 12, no. 6 (2012-06-26), S.2019-2037 |
| Datensatznummer |
250010932
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| Publikation (Nr.) |
 copernicus.org/nhess-12-2019-2012.pdf |
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| Zusammenfassung |
| A deterministic seismic hazard analysis has been carried out for various sites of
the major cities (Ahmedabad, Surat, Bhuj, Jamnagar and Junagadh) of the Gujarat
region in India to compute the seismic hazard exceeding a certain level in terms
of peak ground acceleration (PGA) and to estimate maximum possible PGA at
each site at bed rock level. The seismic sources in Gujarat are very
uncertain and recurrence intervals of regional large earthquakes are not
well defined. Because the instrumental records of India specifically in the
Gujarat region are far from being satisfactory for modeling the seismic
hazard using the probabilistic approach, an attempt has been made in this
study to accomplish it through the deterministic approach. In this regard,
all small and large faults of the Gujarat region were evaluated to
obtain major fault systems. The empirical relations suggested by earlier
researchers for the estimation of maximum magnitude of earthquake motion with
various properties of faults like length, surface area, slip rate, etc. have been
applied to those faults to obtain the maximum earthquake magnitude. For the
analysis, seven different ground motion attenuation relations (GMARs) of
strong ground motion have been utilized to calculate the maximum horizontal ground
accelerations for each major city of Gujarat. Epistemic uncertainties in the
hazard computations are accounted for within a logic-tree framework by
considering the controlling parameters like b-value, maximum magnitude and
ground motion attenuation relations (GMARs). The corresponding deterministic
spectra have been prepared for each major city for the 50th and 84th
percentiles of ground motion occurrence. These deterministic spectra are
further compared with the specified spectra of Indian design code
IS:1893-Part I (2002) to validate them for further practical use. Close
examination of the developed spectra reveals that the expected ground motion
values become high for the Kachchh region i.e. Bhuj city and moderate in the
Mainland Gujarat, i.e. cities of Surat and Ahmedabad. The seismic ground motion
level in the Saurashtra is moderate but marginally differs from that as
presently specified in IS:1893-Part I (2002). Based on the present study, the
recommended PGA values for the cities studied are 0.13 g, 0.15 g, 0.64 g,
0.14 g and 0.2 g for Ahmedabad city, Surat City, Bhuj City, Jamnagar City and
Junagadh city, respectively. The prepared spectra can be further used for
seismic resistant design of structures within the above major city
boundaries of Gujarat to quantify seismic loading on structures. |
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