Seismic Hazard Estimation in East China Offshore Areas

2013 ◽  
Vol 690-693 ◽  
pp. 1158-1167
Author(s):  
Li Fang Zhang ◽  
Yan Ju Peng ◽  
Zhen Ming Wang

In this study, we chose East China offshore areas as study region(N25°~41°,E117°~126°).According to the tectonic environments and characteristics of earthquake the seismotectonic units were established, taking Gaussian spatially smoothing only based on the input earthquake catalog, and fault-rupture-oriented elliptical smoothing to calculate the seismic activity rate in each cells. The maps for the distribution of horizontal peak ground acceleration with 10% probability of exceedance in 50 years were obtained through using the method of seismic hazard analysis based on cell source. While the total number of earthquakes unchanged, two-stage smoothing procedure deals with the error of epicenter location, contains the seismotectonic information in elliptical smoothing seismicity model. This method build up a simple and easy methodology of probabilistic seismic hazard analysis, especially for those place where not yet been clearly master the seismic tectonic information and with distributed Seismic activity.

2020 ◽  
Vol 5 (3) ◽  
pp. 15-25
Author(s):  
Mhd Azri Pangaribuan ◽  
Syamsurijal Rasimeng ◽  
Karyanto Karyanto ◽  
Rudianto Rudianto

Analysis of seismic hazard estimation is one method for estimating the effect of earthquakes. The purpose of this study was to determine the maximum value of ground acceleration in bedrock or PGA values for the Lampung Province region. This analysis of seismic hazard estimation is carried out by a probabilistic seismic hazard analysis (PSHA) method. In the process of estimating the influence of earthquakes, the PSHA method principally uses 3 types of earthquake sources, namely the source of background earthquakes, subduction earthquakes (earthquake subduction) and fault earthquakes (faut). The calculation of the estimated seismic hazard value is carried out using the 2007 USGS PSHA program. The distribution of seismic hazard values for the Lampung Province region on bedrock with a 500-year return period or a 10% probability on the PGA condition (T = 0) is 0.1 g to 1, 3 g and a 2500 year return period or a probability of 2% in the PGA condition (T = 0) is 0.1 g to 1.3 g.


Author(s):  
G. H. McVerry

Probabilistic techniques for seismic hazard analysis have
come into vogue in New Zealand for both the assessment of major projects and the development and review of seismic design codes. However, there are considerable uncertainties in the modelling
 of the strong-motion attenuation, which is necessarily based largely on overseas data. An excellent agreement is obtained between an average 5% damped response spectrum for New Zealand alluvial sites in the 20 to 59 km distance range and 5.4 to 6.0 magnitude class and that given by a Japanese model. Unfortunately, this corresponds to only about half the amplitude levels of 150 year spectra relevant to code design. The much more rapid decay
of ground shaking with distance in New Zealand has led to a considerable modification based on maximum ground acceleration
data from the Inangahua earthquake of the distance-dependence
of the Japanese response spectra model. Less scatter in New Zealand data has resulted in adopting a lower standard deviation for the attenuation model, which is important in reducing the considerable "probabilistic enhancement" of the hazard estimates. Regional differences in attenuation shown by intensities are difficult to resolve from the strong-motion acceleration data, apart from lower accelerations in Fiordland.


2020 ◽  
Vol 30 (2) ◽  
pp. 215
Author(s):  
Anggun Mayang Sari ◽  
Afnindar Fakhrurrozi

The geological and seismic-tectonic setting in the Bandung Basin area proliferates the seismicity risk. Thus, it is necessary to investigate the seismic hazards caused by the foremost seismic source that affects the ground motions in the bedrock. This research employed Probability Seismic Hazard Analysis (PSHA) method to determine the peak ground acceleration value. It considers the source of the earthquakes in the radius of 500 km with a return period of 2500 years. The analysis results showed that the Peak Ground Acceleration (PGA) in this region varies from 0.46 g to 0.70 g. It correlates with the magnitude and hypocentre of the dominant earthquake source of the study locations. The PGA value on the bedrock was used as an input to develop the seismic hazard microzonation map. It was composed using the Geographic Information System (GIS) to visualise the result. This research provides a scientific foundation for constructing residential buildings and infrastructure, particularly as earthquake loads in the building structure design calculations. ABSTRACT - Mikrozonasi Bahaya Seismik Berdasarkan Probability Seismic Hazard Analysis di Cekungan Bandung. Kondisi geologi dan seismik-tektonik di Cekungan Bandung meningkatkan risiko kegempaan di wilayah tersebut. Oleh karena itu, perlu dilakukan penelitian tentang bahaya seismik yang disebabkan oleh sumber-sumber gempa di sekitarnya yang mempengaruhi gelombang gempa di batuan dasar. Penelitian ini menggunakan metode Probability Seismic Hazard Analysis (PSHA) untuk menentukan nilai percepatan gelombang gempa di batuan dasar. Lebih lanjut penelitian ini menggunakan sumber gempa dalam radius 500 km dengan periode perulangan 2500 tahun. Hasil analisis menunjukkan bahwa Peak Ground Acceleration (PGA) di wilayah ini bervariasi dari 0,46 g hingga 0,70 g. Hal ini berkorelasi dengan magnitudo dan jarak hiposenter sumber gempa dominan terhadap lokasi penelitian. Nilai PGA di batuan dasar digunakan sebagai input data dalam pembuatan peta mikrozonasi bahaya seismik. Peta mikrozonasi bahaya seismik disusun dan divisualisasikan menggunakan Sistem Informasi Geografis (SIG). Luaran penelitian ini menghasilkan landasan ilmiah pada konstruksi bangunan tempat tinggal dan infrastruktur, khususnya sebagai pembebanan gempa dalam perhitungan desain struktur bangunan.


2020 ◽  
Vol 9 (2) ◽  
pp. 116
Author(s):  
Rohima Wahyu Ningrum ◽  
Wiwit Suryanto ◽  
Hendra Fauzi ◽  
Estuning Tyas Wulan Mei

The earthquake that occurred in the West Halmahera region was very detrimental, even though the human casualties were not very significant. But it will affect the stability and capacity of a region in terms of regional development. The mapping of earthquake-prone areas is carried out by a probabilistic seismic hazard analysis (PSHA) method to analyze soil movement parameters, namely Peak Ground Acceleration so that it can determine earthquake-prone areas in West Halmahera. The results of seismic hazard analysis show that the West Halmahera area is an area that is relatively prone to earthquake hazards because it is still strongly influenced by subduction (megathrust) earthquakes from the Philippine plate, Maluku sea and Sangihe. This is indicated by the value of earthquake acceleration on the Peak Ground Acceleration for the 500 year return period of around 0.38 - 3.69 g and 0.30 - 3.69 g for the 2500 year return period.


2013 ◽  
Vol 479-480 ◽  
pp. 1061-1065
Author(s):  
Cheng Yu Pan ◽  
Yuan Cheih Wu ◽  
Chih Wei Chang

Tatun volcano group is located in north Taiwan and near Taipei Basin where several million people live there. Although it provides hot spring and landscape for citizens and keeps calm most of time, the threat remains, particularly for the two nearby nuclear power plants. This paper discusses the seismic hazard of volcanic seismic source including source characterization of Tatun volcano group, probabilistic seismic hazard analysis (PSHA), and its preliminary seismic hazard result. Based on nuclear regulatory requirement for PSHA, the uncertainties of source parameters are vital, such as geometry, maximum earthquake, and activity relating earthquake catalog selection, so the first-time seismic source characterization workshop for volcano is held to let domestic experts discuss their hypotheses and investigation result. Hence, the renewed source parameters can represent current geo-science for Tatun volcanic seismic source, and the process of PSHA can lead the better way to combine the result of different research projects for Tatun volcano.


2020 ◽  
Vol 36 (1_suppl) ◽  
pp. 44-68 ◽  
Author(s):  
Henremagne C Peñarubia ◽  
Kendra L Johnson ◽  
Richard H Styron ◽  
Teresito C Bacolcol ◽  
Winchelle Ian G Sevilla ◽  
...  

The Philippine archipelago is tectonically complex and seismically hazardous, yet few seismic hazard assessments have provided national coverage. This article presents an updated probabilistic seismic hazard analysis for the nation. Active shallow crustal seismicity is modeled by faults and gridded point sources accounting for spatially variable occurrence rates. Subduction interfaces are modeled with faults of complex geometry. Intraslab seismicity is modeled by ruptures confined to the slab volume. Source geometries and earthquake rates are derived from seismicity catalogs, geophysical data sets, and historic-to-paleoseismic constraints on fault slip rates. The ground motion characterization includes models designed for global use, with partial constraint by residual analysis. Shallow crustal faulting near metropolitan Manila, Davao, and Cebu dominates shaking hazard. In a few places, peak ground acceleration with 10% probability of exceedance in 50 years on rock reaches 1.0 g. The results of this study may have utility for defining the design base shear in the National Structural Code of the Philippines.


2014 ◽  
Vol 1065-1069 ◽  
pp. 1530-1534
Author(s):  
Zhuo Juan Xie ◽  
Yue Jun Lu

The spatial distribution function assigns seismicity parameters of seismic zone and belt to the potential earthquake source area seismic by the magnitude interval, determination of the spatial distribution function is one of the key technologies to comprehensive probabilistic seismic hazard analysis methods, and the results will directly influence seismic hazard analysis results of the calculated sites. However, the spatial distribution functions are hard to get by statistics due to serious lack of seismic samples, and evaluation factors used in the actual work are too complex and not independent, the spatial distribution function is lack of reliability. In this paper, Bohai seismic tectonic area is chosen as an example; geological data are obtained from the newly built offshore oil platform engineering in recent decades, while seismic activity data are obtained by checking from historical difficult seismic parameters. Five factors are adopted in this area, including potential seismic focus area, seismic tectonic, seismic activity level, long-term forecasts, and strong earthquake recurrence interval and construct empty segment. Spatial distribution function of Bohai Sea earthquake structure area is obtained by weighted comprehension; it reflects the spatial and temporal heterogeneity of seismic activities in the area, and provides the calculation parameters for the probabilistic seismic hazard analysis.


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