scholarly journals A seismic hazard analysis considering uncertainty during earthquake magnitude conversion

2013 ◽  
Vol 1 (3) ◽  
pp. 2109-2126
Author(s):  
J. P. Wang ◽  
Y. Xu

Abstract. The magnitude of earthquakes can be described with different units, such as moment magnitude Mw and local magnitude ML. A few empirical relationships between the two have been suggested, such as the model calibrated with the earthquake data in Taiwan. Understandably, such a conversion relationship through regression analysis is associated with some error because of inevitable data scattering. Therefore, the underlying scope of this study is to conduct a seismic hazard analysis, during which the uncertainty from earthquake magnitude conversion was properly taken into account. With a new analytical framework developed for this task, it was found that there is a 10% probability in 50 yr that PGA could exceed 0.28 g at the study site in North Taiwan.

2021 ◽  
Author(s):  
Abhik Paul ◽  
Pradipta Chakrabortty ◽  
Avijit Burman ◽  
Sapan Kumar

Abstract This article presents the results of a probabilistic seismic hazard analysis (PSHA) for Sitamarhi, Bihar considering the region-specific maximum magnitude and ground motion prediction equation (GMPEs). North Bihar region is one of the seismically unstable areas in India facing several destructive earthquakes for the Himalayan Mountains that was created by the collision of Indian and Eurasian plate. The Gutenberg-Richter (G-R) seismic hazard parameter ‘a’ and ‘b’ have been evaluated by considering the available local earthquake data. Earthquake data were collected from the United States geological survey (USGS), Indian Meteorological Department (IMD), New Delhi, Seismotectonic Atlas of India (GIS 2000) within 500 km radius of the study area, and 62 seismotectonic sources were identified and considered in this study. Seismic source zones for the region have been defined based on large-scale geological features, which are used for assigning the maximum possible earthquake potential. Estimated PGA values are 0.89 g and 0.61 g for the 2% and 10% probabilities of exceedance in 50 years. The results showed that West Patna fault and Sitamarhi Fault are the two main faults, which contribute maximum in the peak ground acceleration (PGA) values for Sitamarhi region.


Author(s):  
Douglas G. Honegger ◽  
Mujib Rahman ◽  
Humberto Puebla ◽  
Dharma Wijewickreme ◽  
Anthony Augello

Terasen Gas Inc. (Terasen) operates a natural gas supply and distribution system situated within one of the zones of the highest seismic activity in Canada. The region encompasses significant areas underlain by marine, deltaic, and alluvial soil deposits, some of which are considered to be susceptible to liquefaction and large ground movements when subjected to earthquake ground shaking. Terasen undertook an assessment of seismic risks to its transmission and key intermediate pressure pipelines in the Lower Mainland in 1994 [1]. The seismic assessment focused on approximately 500 km of steel pipelines ranging from NPS 8 to NPS 42 and operating at pressures from 1900 to 4020 kPa. The 1994 risk assessment provided the basis for detailed site-specific assessment and seismic upgrade programs to retrofit its existing system to reduce risks to acceptable levels. While the general approach undertaken in 1994 remains technically sound, advancements have been made over the past 15 years in the understanding of earthquake hazards and their impact on pipelines. In particular, estimates of the earthquake ground shaking hazard in British Columbia as published by Geological Survey of Canada (GSC) have recently been updated and incorporated into the 2005 National Building Code of Canada (NBCC). In addition, empirical methods of estimating lateral spread ground displacements have been improved as new case-history information has become available. Given these changes, Terasen decided in 2009 to reexamine the seismic risk to Terasen’s pipelines. The scope of the updated seismic risk study was expanded over that in 1994 to include pipelines on Vancouver Island and the Interior of British Columbia. For regional assessments, estimates of lateral spread displacements are necessarily based upon empirical formulations that relate displacement to variables of earthquake severity (earthquake magnitude and distance), susceptibility to liquefaction (density, grain size, fines content), and topography (distance from a river bank or ground slope). Implementing empirical formulae with the results of probabilistic seismic hazard calculations is complicated by the fact that the empirical approach requires earthquake magnitude and distance, as a parametric couple, to be related to the ground shaking severity. However, but such a relationship does not exist in the estimates of mean or modal earthquake magnitude and distance disaggregated from a probabilistic seismic hazard analysis. This paper presents an overview of the approach to regional risk assessment undertaken by Terasen and discusses the unique approach adopted for determining lateral spread displacements consistent with the probabilistic seismic hazard analysis.


KURVATEK ◽  
2017 ◽  
Vol 1 (2) ◽  
pp. 41-47
Author(s):  
Marinda noor Eva

Penelitian mengenai daerah rawan gempa bumi ini menggunakan Metode Probabilistic Seismic Hazard Analysis (PSHA) di Provinsi Sulawesi Barat, dengan tujuan untuk memetakan tingkat kerawanan bahaya gempa bumi di Kabupaten Mamasa. Penelitian ini menggunakan data kejadian gempa bumi di Pulau Sulawesi dan sekitarnya dari tahun 1900 – 2015. Hasil pengolahan PSHA menggunakan Software Ez-Frisk 7.52 yang menghasilkan nilai hazard di batuan dasar pada kondisi PGA (T = 0,0 sekon), dengan periode ulang 500 tahun dan 2500 tahun berkisar antara (149,54 – 439,45) gal dan (287,18 – 762,81) gal. Nilai hazard di batuan dasar dengan kondisi spektra T = 0,2 sekon untuk periode ulang 500 tahun dan 2500 tahun adalah (307,04 – 1010,90) gal dan (569,48 – 1849,78) gal. Nilai hazard di batuan dasar dengan kondisi spektra T = 1,0 sekon untuk periode ulang 500 tahun dan 2500 tahun diperoleh nilai (118,01 – 265,75) gal dan (223,74 – 510,92) gal. Berdasarkan analisis PSHA, nilai PGA di Provinsi Sulawesi Barat dominan dipengaruhi oleh sumber gempa sesar.


Author(s):  
V.A. Mironov ◽  
S.A. Peretokin ◽  
K.V. Simonov

The article is a continuation of the software research to perform probabilistic seismic hazard analysis (PSHA) as one of the main stages in engineering seismic surveys. The article provides an overview of modern software for PSHA based on the Monte Carlo method, describes in detail the work of foreign programs OpenQuake Engine and EqHaz. A test calculation of seismic hazard was carried out to compare the functionality of domestic and foreign software.


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