Preparation of the New Zealand earthquake catalogue for a probabilistic seismic hazard analysis

2001 ◽  
Vol 34 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Peter McGinty
Keyword(s):  
New Zealand ◽  
Seismic Hazard ◽  
Hazard Analysis ◽  
Large Earthquake ◽  
Return Time ◽  
Earthquake Catalogue ◽  
Probabilistic Seismic Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Probabilistic Seismic Hazard ◽  
Data Sets

The seismic hazard from ground motions during a New Zealand earthquake is variable, and is dependent on the different tectonic processes that occur throughout the country. A modem probabilistic seismic hazard analysis (PSHA) combines various data sets to take account of these different environmental effects and rates of occurrence. Earthquake catalogue data can be used to give the rate of background or distributed seismicity in historical times, while paleoseismic data can be used to constrain the return time of large earthquakes. The background seismicity is assumed to occur as a time-independent Poisson process. To apply this assumption to a new PSHA of New Zealand, completeness levels for the New Zealand earthquake catalogue were established, and aftershocks or clusters of events that occurred close together in both space and time were removed from the catalogue. The level of hazard in a region can be depth-dependent, that is the risk of a large earthquake may come from a shallow crustal event or a deep subduction zone event, both having the same epicentral location but resulting in different levels of damage. The New Zealand earthquake catalogue has too many events that have been assigned restricted depths to be ignored. These events have been statistically redistributed into shallow crustal zones or deep subducted slab zones based on the last eleven years of catalogue data, when improvements in technology have reduced the number of restricted events.

Probabilistic seismic hazard analysis and design earthquakes: Closing the loop

1995 ◽  
Vol 85 (5) ◽  
pp. 1275-1284 ◽  
Author(s):  
Robin K. McGuire
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Large Earthquake ◽  
Probabilistic Seismic Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Probabilistic Seismic Hazard ◽  
Ground Shaking ◽  
Uniform Hazard Spectrum ◽  
Analysis And Design ◽  
Design Earthquake

Abstract Probabilistic seismic hazard analysis (PSHA) is conducted because there is a perceived earthquake threat: active seismic sources in the region may produce a moderate-to-large earthquake. The analysis considers a multitude of earthquake occurrences and ground motions, and produces an integrated description of seismic hazard representing all events. For design, analysis, retrofit, or other seismic risk decisions a single “design earthquake” is often desired wherein the earthquake threat is characterized by a single magnitude, distance, and perhaps other parameters. This allows additional characteristics of the ground shaking to be modeled, such as duration, nonstationarity of motion, and critical pulses. This study describes a method wherein a design earthquake can be obtained that accurately represents the uniform hazard spectrum from a PSHA. There are two key steps in the derivation. First, the contribution to hazard by magnitude M, distance R, and ɛ must be maintained separately for each attenuation equation used in the analysis. Here, ɛ is the number of standard deviations that the target ground motion is above or below the median predicted motion for that equation. Second, the hazard for two natural frequencies (herein taken to be 10 and 1 Hz) must be examined by seismic source to see if one source dominates the hazard at both frequencies. This allows us to determine whether it is reasonable to represent the hazard with a single design earthquake, and if so to select the most-likely combination of M, R, and ɛ (herein called the “beta earthquake”) to accurately replicate the uniform hazard spectrum. This closes the loop between the original perception of the earthquake threat, the consideration of all possible seismic events that might contribute to that threat, and the representation of the threat with a single (or few) set of parameters for design or analysis.

scholarly journals Analysis of Changes in Seismicity Pattern for Probabilistic Seismic Hazard Analysis (PSHA) and Mitigation: Mapping Probability Difference before the Large Earthquake and Its Implementation in PSHA & Mitigation around Northern Sumatra

2020 ◽  
Author(s):  
Wahyu Triyoso ◽  
Tedi Yudistira ◽  
David P. Sahara
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Large Earthquake ◽  
Probabilistic Seismic Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Probabilistic Seismic Hazard ◽  
Ground Acceleration ◽  
Seismicity Rate ◽  
Seismicity Pattern ◽  
Major Earthquake

Abstract The probability difference before the occurrence of a large earthquake is mapped in the northern part of Sumatra, taking the range of Region Time Length (RTL) before a major earthquake (December 26, 2004) around 15 years. By normalizing the absolute value of probability difference between two periods of RTL and before RTL, the Seismic Quiescence Index (SQI) is then defined. Probability difference analysis is done by dividing observations of shallow earthquake periods into two periods based on the similarity gradient of the annual earthquake production, namely 1963-1990 and 1991-November 2004. The results showed that areas with relatively high SQI were consistent with the presence of major earthquake events after November 2004 to 2016 that are sorted by a radius of 300 km with the center point being the epicenter position of the December 2004 earthquake. The implementation of the SQI was then used for probabilistic seismic hazards study and analysis based on an integratedmodel that is derived based on the estimated of seismicity rate of around the subduction zone and active fault of Sumatra Fault Zone (SFZ) sources. The map of Probabilistic Seismic Hazard Analysis (PSHA) is then constructed based onPeak Ground Acceleration (PGA) estimated for a 10% Probability Exceedance (PE) level in 50 years. The results of this study may be very useful for earthquake mitigation and modeling efforts for PSHA going forward.

PEMETAAN DAERAH RENTAN GEMPA BUMI SEBAGAI DASAR PERENCANAAN TATA RUANG DAN WILAYAH DI PROVINSI SULAWESI BARAT

KURVATEK ◽  
2017 ◽  
Vol 1 (2) ◽  
pp. 41-47
Author(s):  
Marinda noor Eva
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Probabilistic Seismic Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Probabilistic Seismic Hazard

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.

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