scholarly journals Probabilistic seismic hazard analysis for Northern Tanzania Divergence Region and the adjoining areas

2021 ◽  
Vol 47 (2) ◽  
pp. 862-876
Author(s):  
Michael M Msabi ◽  
Richard W Ferdinand
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Tectonic Setting ◽  
Seismic Source ◽  
Attenuation Relations ◽  
Design Engineers ◽  
Earthquake Resistant Design ◽  
Northern Tanzania ◽  
Source Zones ◽  
Hazard Levels

This paper presents the seismic hazard levels for the Northern Tanzania Divergence (NTD) and adjoining areas by using area seismic source zones. The 15 source zones were considered based on the major geological and tectonic features, faulting style, and seismicity trends. For each source, earthquake recurrence parameters were computed by using the earthquake catalogue with events compiled from 1956 to 2011. The peak ground accelerations (PGA) and spectral accelerations (SA) at 0.2 and 2.0 second, respectively, were computed for a 10% probability of exceedance in 50 years at sites defined by a 0.1° x 0.1° grid. The recurrence parameters of 15 zones and attenuation relations developed by Akkar et al. (2014) and Chiou and Youngs (2014) were integrated in a logic tree. Obtained results that are presented as hazard maps show strong spatial variations ranging from 60 to 330 cm/s/s for PGA, from 100 to 650 cm/s/s at 0.2 sec and from 6 to 27 cm/s/s at 2 sec for 475 years mean return period and 5% damping. Hazard levels depict the general tectonic setting of the study area with the western (Eyasi-Wembere) and central (Natron-Manyara-Balangida) rift segments having relatively high PGA values compared with the eastern Pangani rift. This work provides indications of seismic hazards to policymakers and planners during planning and guidelines for earthquake-resistant design engineers. Keywords: Homogeneous Earthquakes Catalogue; GMPE; PSHA; NTD

scholarly journals SEISMIC HAZARD MICROZONATION BASED ON PROBABILITY SEISMIC HAZARD ANALYSIS IN BANDUNG BASIN

2020 ◽  
Vol 30 (2) ◽  
pp. 215
Author(s):  
Anggun Mayang Sari ◽  
Afnindar Fakhrurrozi
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Residential Buildings ◽  
Hazard Analysis ◽  
Tectonic Setting ◽  
Seismic Source ◽  
Structure Design ◽  
Seismic Hazard Analysis ◽  
Ground Acceleration ◽  
Design Calculations

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.

scholarly journals Assessment of earthquake hazard in Turkey and neighboring

1999 ◽  
Vol 42 (6) ◽  
Author(s):  
M. Erdik ◽  
Y. A. Biro ◽  
T. Onur ◽  
K. Sesetyan ◽  
G. Birgoren
Keyword(s):  
Seismic Hazard ◽  
Site Selection ◽  
Hazard Analysis ◽  
Tectonic Setting ◽  
Earthquake Hazard ◽  
Seismic Source ◽  
Return Periods ◽  
Engineering Structures ◽  
Contour Maps ◽  
Attenuation Relationships

The aim of this study is to conduct a probabilistic seismic hazard analysis for Turkey and neighboring regions, using the most recently developed attenuation relationships. The seismicity database is compiled from numerous sources, and the tectonic setting of the region has been studied in detail. Utilizing these two major categories of information together with the selected attenuation relationships, the seismic source zones are determined, and PGA contour maps are produced for specific return periods. The study is intended to serve as a reference for more advanced approaches and to stimulate discussion and suggestions on the database, assumptions and the inputs, and to pave the way for the probabilistic assessment of seismic hazard in the site selection and the design of engineering structures.

scholarly journals Determination of Local Site-Specific Spectra Using Probabilistic Seismic Hazard Analysis for Bitlis Province, Turkey

2015 ◽  
Vol 19 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Ercan Işık ◽  
Mustafa Kutanis
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Response Spectra ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Source Characterization ◽  
Site Specific ◽  
Attenuation Relationships

<p>In this study, site-specific earthquake spectra for Bitlis province in Lake Van Basin has been obtained. It is noteworthy that, in probabilistic seismic hazard assessment, as a first stage data from geological studies and records from the instrumental period were compiled to make a seismic source characterization for the study region.The probabilistic seismic hazard curves for Bitlis were developed based on selected appropriate attenuation relationships, at rock sites, with a probability of exceedance 2%, 10% and 50% in 50 year periods. The obtained results were compared with the spectral responses proposed for seismic evaluation and retrofit of the building structure in Turkish Earthquake Code, Section 2. At the end of this study, it is apprehended that the Code proposed earthquake response spectra are not sufficient for the performance evaluation of the existing structures and the current estimations show that the potential seismic hazard research of the Turkey is underestimated in the code.Therefore, site- specific design spectra for the region should be developed, which reflect the characteristics of local sites.</p><p> </p><p><strong>Determinación de espectros de sitio específico locales a través del análisis probabilístico de amenazas sísmicaspara la provincia de Bitlis, Turquía</strong></p><p> </p><p><strong>Resumen</strong></p>En este estudio se obtuvieron espectros de terremoto de sitio específico para la cuenca del Lago de Van, en la provincia de Bitlis, al este de Turquía. La primera fase del trabajo consistió en una evaluación probabilística de riesgo sísmico donde se compilaron los estudios geológicos y registros del período instrumental para hacer una caracterización de fuente sísmica en la región de estudio. Las curvas de amenaza sísmica para la provincia de Bitlis se desarrollaron con base en las relaciones de atenuación apropiada seleccionadas en los sitios rocosos, con una probabilidad de exceso de 2 %, 10 % y 50 % durante 50 años. Los resultados obtenidos se compararon con las respuestas de espectro propuestas para la evaluación sísmica y modernización de estructuras contempladas en el Código de Terremoto de Turquía, en la sección 2. En la parte final de este trabajo se comprende que las respuestas de espectros de terremoto propuestos en el código no son suficientes para la evaluación de desempeño de las estructuras existentes y que las estimaciones actuales muestran que la investigación de amenazas potenciales sísmicas en Turquía está subestimada en el código. Por lo tanto, el diseño de espectros de sitio específico para la región se debe desarrollar, ya que permitiría conocer las singularidades locales.</p>

scholarly journals Seismic hazard maps of Peshawar District for various return periods

2020 ◽  
Vol 20 (6) ◽  
pp. 1639-1661
Author(s):  
Khalid Mahmood ◽  
Naveed Ahmad ◽  
Usman Khan ◽  
Qaiser Iqbal
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Target Location ◽  
Epistemic Uncertainty ◽  
Hazard Analysis ◽  
Source Parameters ◽  
Seismic Source ◽  
Return Periods ◽  
Hazard Maps ◽  
Seismic Hazard Maps

Abstract. Probabilistic seismic hazard analysis of Peshawar District has been performed for a grid size of 0.01∘. The seismic sources for the target location are defined as the area polygon with uniform seismicity. The earthquake catalogue was developed based on the earthquake data obtained from different worldwide seismological networks and historical records. The earthquake events obtained at different magnitude scales were converted into moment magnitude using indigenous catalogue-specific regression relationships. The homogenized catalogue was subdivided into shallow crustal and deep-subduction-zone earthquake events. The seismic source parameters were obtained using the bounded Gutenberg–Richter recurrence law. Seismic hazard maps were prepared for peak horizontal acceleration at bedrock level using different ground motion attenuation relationships. The study revealed the selection of an appropriate ground motion prediction equation is crucial for defining the seismic hazard of Peshawar District. The inclusion of deep subduction earthquakes does not add significantly to the seismic hazard for design base ground motions. The seismic hazard map developed for shallow crustal earthquakes, including also the epistemic uncertainty, was in close agreement with the map given in the Building Code of Pakistan Seismic Provisions (2007) for a return period of 475 years on bedrock. The seismic hazard maps for other return periods i.e., 50, 100, 250, 475 and 2500 years, are also presented.

scholarly journals Time independent seismic hazard analysis of Greece deduced from Bayesian statistics

2003 ◽  
Vol 3 (1/2) ◽  
pp. 129-134 ◽  
Author(s):  
T. M. Tsapanos ◽  
G. A. Papadopoulos ◽  
O. Ch. Galanis
Keyword(s):  
Seismic Hazard ◽  
Bayesian Statistics ◽  
Hazard Analysis ◽  
Earthquake Occurrence ◽  
Time Intervals ◽  
Seismogenic Sources ◽  
Earthquake Resistant Design ◽  
Seismogenic Source ◽  
Earthquake Resistant ◽  
Of Greece

Abstract. A Bayesian statistics approach is applied in the seismogenic sources of Greece and the surrounding area in order to assess seismic hazard, assuming that the earthquake occurrence follows the Poisson process. The Bayesian approach applied supplies the probability that a certain cut-off magnitude of Ms = 6.0 will be exceeded in time intervals of 10, 20 and 75 years. We also produced graphs which present the different seismic hazard in the seismogenic sources examined in terms of varying probability which is useful for engineering and civil protection purposes, allowing the designation of priority sources for earthquake-resistant design. It is shown that within the above time intervals the seismogenic source (4) called Igoumenitsa (in NW Greece and west Albania) has the highest probability to experience an earthquake with magnitude M > 6.0. High probabilities are found also for Ochrida (source 22), Samos (source 53) and Chios (source 56).

scholarly journals Uncertainties in attenuation relations for New Zealand seismic hazard analysis

1986 ◽  
Vol 19 (1) ◽  
pp. 28-39 ◽  
Author(s):  
G. H. McVerry
Keyword(s):  
New Zealand ◽  
Seismic Hazard ◽  
Hazard Analysis ◽  
Response Spectrum ◽  
Strong Motion ◽  
Seismic Hazard Analysis ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Ground Shaking ◽  
Acceleration Data

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.

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