scholarly journals ANALISA KURVA HAZARD PADA KABUPATEN TAMBRAUW DENGAN MENGGUNAKAN BEBERAPA FUNGSI ATENUASI

2018 ◽  
Author(s):  
Lilis Fitri Handayani ◽  
Serly Marlina

Kabupaten Tambrauw adalah salah satu kabupaten di Provinsi Papua Barat, Indonesia. Pusat pemerintahan berada di Fef. Kabupaten Tambrauw mempunyai luas wilayah 11 529,19 Km², yang terdiri dari daratan dan lautan. Secara geografis Kabupaten Tambrauw pada sebelah Utara berbatasan dengan Samudera Pasifik, sebelah Selatan berbatasan dengan Kabupaten Sorong Selatan dan sebelah Timur berbatasan dengan Distrik Sidey dan Kabupaten Manokwari. Ada beberapa metode yang dapat digunakan dalam Seismic Hazard Assessment untuk membuat prediksi kejadian gempa di masa yang akan datang (gempa rencana). Pada analisa ini, Seismic Hazard Assessment menggunakan The Line Source Method untuk membuat Hazard curve yang dapat memperkirakan kejadian gempa di Kabupaten Tambrauw. Kurva hazard dibuat menggunakan fungsi atenuasi Esteva (1970), fungsi Atenuasi Hou & Hu (1991), fungsi Atenuasi Ambraseys (1995) dan fungsi Atenuasi Crouse-Mc Guirre (1996). Hasil analisa menunjukkan besarnya nilai percepatan tanah (ground acceleration) akan semakin mengecil pada jarak atau radius yang semakin jauh. Analisis kurva hazard pada daerah Kabupaten Tambrauw akibat pergeseran lempeng akan menunjukkan nilai terbesar pada saat menggunakan fungsi atenuasi Hou & Hu (1991) dan analisis kurva hazard pada daerah Kabupaten Tambrauw akibat pergeseran lempeng akan menunjukkan nilai terkecil pada saat menggunakan fungsi atenuasi Crouse-McGuirre (1996), F = 0.

1999 ◽  
Vol 42 (6) ◽  
Author(s):  
D. Giardini ◽  
G. Grünthal ◽  
K. M. Shedlock ◽  
P. Zhang

The Global Seismic Hazard Assessment Program (GSHAP), a demonstration project of the UN/International Decade of Natural Disaster Reduction, was conducted in the 1992-1998 period with the goal of improving global standards in seismic hazard assessment. The GSHAP Global Seismic Hazard Map has been compiled by joining the regional maps produced for different GSHAP regions and test areas; it depicts the global seismic hazard as Peak Ground Acceleration (PGA) with a 10% chance of exceedance in 50 years, corresponding to a return period of 475 years.


2010 ◽  
Vol 10 (1) ◽  
pp. 25-39 ◽  
Author(s):  
G-A. Tselentis ◽  
L. Danciu

Abstract. Seismic hazard assessment represents a basic tool for rational planning and designing in seismic prone areas. In the present study, a probabilistic seismic hazard assessment in terms of peak ground acceleration, peak ground velocity, Arias intensity and cumulative absolute velocity computed with a 0.05 g acceleration threshold, has been carried out for Greece. The output of the hazard computation produced probabilistic hazard maps for all the above parameters estimated for a fixed return period of 475 years. From these maps the estimated values are reported for 52 Greek municipalities. Additionally, we have obtained a set of probabilistic maps of engineering significance: a probabilistic macroseismic intensity map, depicting the Modified Mercalli Intensity scale obtained from the estimated peak ground velocity and a probabilistic seismic-landslide map based on a simplified conversion of the estimated Arias intensity and peak ground acceleration into Newmark's displacement.


2018 ◽  
Author(s):  
Daniel Weijie Loi ◽  
Mavinakere Eshwaraiah Raghunandan ◽  
Varghese Swamy

Abstract. Seismic hazard assessments – both deterministic and probabilistic, for Peninsular Malaysia have been carried out using peak ground acceleration (PGA) data recorded between 2004 and 2016 by the Malaysian Meteorological Department – using triaxial accelerometers placed at 19 seismic stations within the peninsula and monitored. Seismicity source modelling for the deterministic seismic hazard assessment (DSHA) used historical point sources whereas in the probabilistic (PSHA) approach, line and areal sources were used. The earthquake sources comprised the Sumatran Subduction Zone (SSZ), Sumatran Fault Zone (SFZ), and local intraplate (LI) faults. Gutenberg–Richter law b-value for the various zones identified within the SSZ ranged between 0.56 and 1.06 (mean = 0.83) and that for the zones within SFZ, between 0.53 and 1.13 (mean = 0.84). Suitable ground motion prediction equations (GMPEs) for Peninsular Malaysia along with other pertinent information were used for constructing a logic tree for PSHA of the region. The DSHA critical-worst scenario suggests PGAs of 0.07–0.80 ms−2, whilst the PSHA suggests mean PGAs of 0.06–0.42 ms−2 and 0.12–0.70 ms−2 at 10 % and 2 % probability of exceedance in 50 years, respectively. Both DSHA and PSHA, despite using different source models and methodologies, conclude that the central-western cities of Peninsular Malaysia located between 2° N and 4° N are most susceptible to high PGAs due to neighbouring active Sumatran sources SFZ and SSZ. Surprisingly, the relatively less active SFZ source with low magnitude seismicity appeared as the major contributor, due to its close proximity. Potential hazard due to SSZ mega-earthquakes should not be dismissed, however. Finally, DSHA performed using the limited intraplate seismic data from the Bukit Tinggi (LI) fault at a reasonable Mw 5.0 predicted a PGA of ~ 0.40 ms−2 at Kuala Lumpur.


2015 ◽  
Vol 58 (1) ◽  
Author(s):  
Shahid Ullah ◽  
Dino Bindi ◽  
Marco Pilz ◽  
Stefano Parolai

<p>It is well known that variability in the surface geology potentially leads to the modification of earthquake-induced ground motion over short distances. Although this effect is of major importance when seismic hazard is assessed at the urban level, it is very often not appropriately accounted for. In this paper, we present a first attempt at taking into account the influence of the shallow geological structure on the seismic hazard assessment for Bishkek, Kyrgyzstan, using a proxy (Vs30) that has been estimated from in situ seismic noise array analyses, and considering response spectral ratios calculated by analyzing a series of earthquake recordings of a temporary seismic network. To highlight the spatial variability of the observed ground motion, the obtained results are compared with those estimated assuming a homogeneous Vs30 value over the whole urban area. The seismic hazard is evaluated in terms of peak ground acceleration (PGA) and spectral acceleration (SA) at different periods (frequencies). The presented results consider the values obtained for a 10% probability of exceedance in 50 years. The largest SA estimated considering a rock site classification of the area (0.43 g) is observed for a period of 0.1 s (10 Hz), while the maximum PGA reaches 0.21 g. When site effects are included through the Vs30 proxy in the seismic hazard calculation, the largest SA, 0.67 g, is obtained for a period of 0.3 s (about 3.3 Hz). In terms of PGA, in this case the largest estimated value reaches 0.31 g in the northern part of the town. When the variability of ground motion is accounted for through response spectrum ratios, the largest SA reaches a value as high as 1.39 g at a period of 0.5 s. In general, considering site effects in the seismic hazard assessment of Bishkek leads to an increase of seismic hazard in the north of the city, which is thus identified as the most hazardous part within the study area and which is more far away from the faults.</p>


2019 ◽  
Vol 55 (1) ◽  
pp. 109 ◽  
Author(s):  
Nikolaos Vavlas ◽  
Anastasia Kiratzi ◽  
Basil Margaris ◽  
George Karakaisis

We carry out a probabilistic seismic hazard assessment (PSHA) for Lesvos Island, in the northeastern Aegean Sea. Being the most populated island in the northern Aegean Sea and hosting the capital of the prefecture, its seismic potential has significant social-economic meaning. For the seismic hazard estimation, the newest version of the R-CRISIS module, which has high efficiency and flexibility in model selection, is used. We incorporate into the calculations eight (8) ground motion prediction equations (GMPEs). The measures used are peak ground acceleration, (PGA), peak ground velocity, (PGV), and spectral acceleration, (SA), at T=0.2 sec representative of the building stock. We calculate hazard curves for selected sites on the island, sampling the southern and northern parts: Mytilene, the capital, the village of Vrisa, Mithymna and Sigri. Hazard maps are also presented in terms of all three intensity measures, for a mean return period of 475 years (or 10% probability of exceedance in 50 years), assuming a Poisson process. Our results are comparable to the predictions of on-going EU hazard models, but higher than the provisions of the Greek Seismic Code. Finally, we perform disaggregation of hazard to depict the relative contribution of different earthquake sources and magnitudes to the results.


2018 ◽  
Vol 18 (9) ◽  
pp. 2387-2408 ◽  
Author(s):  
Daniel Weijie Loi ◽  
Mavinakere Eshwaraiah Raghunandan ◽  
Varghese Swamy

Abstract. Seismic hazard assessments, both deterministic and probabilistic, for Peninsular Malaysia have been carried out using peak ground acceleration (PGA) data recorded between 2004 and 2016 by the Malaysian Meteorological Department using triaxial accelerometers placed at 19 seismic stations on the peninsula. Seismicity source modelling for the deterministic seismic hazard assessment (DSHA) used historical point sources whereas in the probabilistic (PSHA) approach, line and areal sources were used. The earthquake sources comprised the Sumatran subduction zone (SSZ), Sumatran fault zone (SFZ) and local intraplate (LI) faults. Gutenberg–Richter law b value for the various zones identified within the SSZ ranged between 0.56 and 1.06 (mean=0.82) and for the zones within the SFZ, between 0.57 and 1.03 (mean=0.89). Suitable ground motion prediction equations (GMPEs) for Peninsular Malaysia along with other pertinent information were used for constructing a logic tree for PSHA of the region. The DSHA “critical-worst” scenario suggests PGAs of 0.07–0.80 ms−2 (0.7–8.2 percent g), whilst the PSHA suggests mean PGAs of 0.11–0.55 ms−2 (0.5–5.4 percent g) and 0.20–1.02 ms−2 (1.9–10.1 percent g) at 10 % and 2 % probability of exceedance in 50 years, respectively. DSHA and PSHA, despite using different source models and methodologies, both conclude that the central-western cities of Peninsular Malaysia, located between 2 and 4∘ N, are most susceptible to high PGAs, due to neighbouring active Sumatran sources, SFZ and SSZ. Of the two Sumatran sources, surprisingly, the relatively less active SFZ source with low magnitude seismicity appeared as the major contributor due to its proximity. However, potential hazards due to SSZ mega-earthquakes should not be dismissed. Finally, DSHA performed using the limited LI seismic data from the Bukit Tinggi fault at a reasonable moment magnitude (Mw) value of 5.0 predicted a PGA of ∼0.40 ms−2 at Kuala Lumpur.


2020 ◽  
Vol 110 (3) ◽  
pp. 1162-1171
Author(s):  
Hongliu Ran

ABSTRACT Aleatory variability is the natural randomness in a process and can affect probabilistic seismic hazard assessment (PSHA). In this study, considering a simple case of a square areal source zone, I employ Monte Carlo methods to estimate aleatory uncertainties due to random variations in temporal, spatial, and magnitude distribution of seismicity within the zone for PSHA. The results show that (1) uncertainty from aleatory variability in PSHA is significant for areas with low-seismic activity, (2) the ratio of the 85th to 15th percentiles of peak ground acceleration (PGA) decreases as the occurrence rate increases, and (3) accounting for random variations in seismic parameters changes the estimated PGA by more than 10%. My analysis applies to the case in which there are fewer than 10 earthquakes over 50 yr, the site is located outside of the areal source, and b≥1.0. This situation should be considered in PSHA due to the cutoff effect of the magnitude lower limit. In addition, the sensitivity analysis shows that random variations in earthquake magnitude distribution are the largest contributor to aleatory uncertainty in most cases.


2001 ◽  
Vol 17 (3) ◽  
pp. 399-415 ◽  
Author(s):  
Jamal A. Abdalla ◽  
Yahia E-A. Mohamedzein ◽  
A. Abdel Wahab

This paper presents seismic hazard assessment and seismic zoning of Sudan and its vicinity based on probabilistic approach. The area studied lies between 22° E- 45° E and 0° - 24° N. Tectonics of Sudan and its vicinity is first reviewed. An updated NOAA catalogue, containing both historical and instrumental events and covering the period from 700 A.D. to 1993 is then used. Seismic source regions are modeled and relationships between earthquake magnitude and earthquake frequency are established. A modified attenuation relation is used. Seismic hazard assessment is then carried out for 60 km interval grid points. Seismic hazard maps of the studied area based on peak ground acceleration (PGA) for 10% probability of exceedance for time-spans of 50, 100, 200 and 250 years are presented. The results showed that the PGA ranges from 0.02g for low seismic activity regions to around 0.62g for high seismic activity regions. A seismic zone map is also shown for 475 years return period.


2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Cao Dinh Trong ◽  
Xuan-Nam BUI ◽  
Pham NAM HUNG ◽  
Thai ANH TUAN ◽  
Mai XUAN BACH ◽  
...  

This paper presents the seismic hazard assessment for Thuong Tan-Tan My quarries in Di An commune, Binh Duong province, Vietnam. Combination methods of gravity and magneto-telluric were used to estimate the dip angle and the width of the seismic source. The highest water column of 160 m will cause direct stress on the reservoir bottom with a maximum value of 1535.600 kPa and Coulomb stress of 68.693 kPa (at a depth of 2 km). The typical components of natural earthquake hazard (Mn.max = 5.0, depth of 10 km) in Thuong Tan - Tan My reservoir have the following values: peak ground acceleration PGA = 0.073 g ÷ 0.212 g; peak ground velocity PGV = 2.662 cm/s ÷ 7.984 cm/s; peak ground displacement PGD = 0.706 cm ÷ 1.918 cm at 10% probability of exceedance in 50 years. The typical components of triggered earthquake hazard (Mtr.max = 3.5, depth of 6 km) in Thuong Tan - Tan My reservoir have the following values: peak ground acceleration PGA = 0.024 g ÷ 0.172 g; peak ground velocity PGV = 0 ÷ 5.484 cm/s; peak ground displacement PGD = 0.061 cm ÷ 0.461 cm at 10% probability of exceedance in 50 years.


2002 ◽  
Vol 18 (4) ◽  
pp. 615-629 ◽  
Author(s):  
Gideon Leonard ◽  
David M. Steinberg

A modified version of seismic hazard assessment, directed toward planning of emergency relief efforts, is proposed. The method begins with a probabilistic hazard assessment to determine a reference peak ground acceleration (PGA) at a near site, rather than using a reference earthquake of a given magnitude. The reference PGA then serves as a basis for a probabilistic assessment of PGA at more distant sites. The ideas are illustrated by studying seismic hazard for Northern Israel from earthquakes on the northern section of the Dead Sea Rift (DSR). The reference PGA at a site 10 km from the DSR is taken to be 0.3 g, which has a return period estimated to be 320 years. Given an event with PGA of 0.3 g at 10 km, the subsequent analysis for distant sites shows that there is less than a 31% probability of PGA above 0.1 g at 30 km and an 8% probability that the PGA at 50 km will exceed 0.1 g.


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