scholarly journals ZONASI SITE EFFECT DAN ANALISIS BAHAYA PENGUATAN GEMPA MENGGUNAKAN METODE DSHA UNTUK MENENTUKAN PGA DI KABUPATEN SUMBA BARAT DAYA

2020 ◽  
Vol 3 (2) ◽  
pp. 38
Author(s):  
Soulthan Salahudin Al Ayubi ◽  
Karyanto Karyanto ◽  
Nandi Haerudin ◽  
Syamsurijal Rasimeng ◽  
Rahmat C Wibowo
Keyword(s):  
Hazard Analysis ◽  
Ground Surface ◽  
Earthquake Hazard ◽  
Site Effect ◽  
Research Area ◽  
Tectonic Activity ◽  
The South ◽  
Sediment Deposits ◽  
Banda Arc ◽  
Earthquake Record

Southwest Sumba Regency is located in the Banda Arc area. Its position which is very close to the subduction area in the south of Indonesia caused a lot of tectonic activity and earthquake hazard. The arrangement of alluvium, coral, and thick deposits on the island of Sumba makes it prone to earthquake strengthening. Zoning of soil characters using site effects and DSHA method was carried out to determine the danger level of strengthening the Southwest Sumba Regency. Zoning of the site effect soil character uses microtremor data which is correlated with seismic hazard analysis to obtain the PGA values on bedrock and ground surface using the closest earthquake source. The area is dominated by Class 2 and 3 lands (f0 worth 1.333 - 5 Hz) according to the Kanai Classification (1983), with an amplification predominance of 3.8-8.3 times. This indicates that the research area is dominated by thick sediment deposits. The PGA value obtained from the DSHA method is known that Southwest Sumba Regency has a PGA soil of 0.075-0.19 g and a bedrock PGA of 0.067-0.085 g using earthquake record data in Sumba Subduction and Timor Subduction. With PGA estimation, it is known that the level of earthquake disaster vulnerability is high, located in the south of Southwest Sumba Regency which is suspected to be composed of thick sediments and close to the Sumba Subduction and Timor Subduction.Keywords: Site effect, predominant frequency, amplification, earthquake, DSHA, PGA

Modeling of Empirical Transfer Functions with 3D Velocity Structure

2021 ◽  
Author(s):  
Zhifeng Hu ◽  
Daniel Roten ◽  
Kim B. Olsen ◽  
Steven M. Day
Keyword(s):  
Material Properties ◽  
Site Effects ◽  
Velocity Structure ◽  
Transfer Functions ◽  
Site Response ◽  
Hazard Analysis ◽  
Earthquake Hazard ◽  
Site Effect ◽  
3D Models ◽  
Site Amplification

ABSTRACT Empirical transfer functions (ETFs) between seismic records observed at the surface and depth represent a powerful tool to estimate site effects for earthquake hazard analysis. However, conventional modeling of site amplification, with assumptions of horizontally polarized shear waves propagating vertically through 1D layered homogeneous media, often poorly predicts the ETFs, particularly, in which large lateral variations of velocity are present. Here, we test whether more accurate site effects can be obtained from theoretical transfer functions (TTFs) extracted from physics-based simulations that naturally incorporate the complex material properties. We select two well-documented downhole sites (the KiK-net site TKCH05 in Japan and the Garner Valley site, Garner Valley Downhole Array, in southern California) for our study. The 3D subsurface geometry at the two sites is estimated by means of the surface topography near the sites and information from the shear-wave profiles obtained from borehole logs. By comparing the TTFs to ETFs at the selected sites, we show how simulations using the calibrated 3D models can significantly improve site amplification estimates as compared to 1D model predictions. The primary reason for this improvement in 3D models is redirection of scattering from vertically propagating to more realistic obliquely propagating waves, which alleviates artificial amplification at nodes in the vertical-incidence response of corresponding 1D approximations, resulting in improvement of site effect estimation. The results demonstrate the importance of reliable calibration of subsurface structure and material properties in site response studies.

Thematic mapping of the abandoned mining hazard: a pilot study for the South Wales Coalfield

1987 ◽  
Vol 4 (1) ◽  
pp. 255-268 ◽  
Author(s):  
I. Statham ◽  
C. Golightly ◽  
G. Treharne
Keyword(s):  
Back Analysis ◽  
Ground Surface ◽  
Historical Record ◽  
Mining Subsidence ◽  
Present Condition ◽  
Opencast Mining ◽  
The South ◽  
Mining Sites ◽  
South Wales ◽  
Method Of Production

AbstractThe Department of the Environment and the Welsh Office jointly sponsored a South Wales Desk Study into the feasibility of producing thematic maps of the Mining subsidence risk for planners. A method was to be developed and tested for a 25 km2 Pilot Area centred on Ebbw Vale.The study was started by collecting geological and mining data for the Pilot Area and compiling this information on a map. It was then intended to prepare the mining subsidence map from this map by back analysing subsidence incidents to determine the hazardous areas. This simple approach could not be followed for two reasons. First, the record of mining was incomplete and it was therefore necessary to define ‘worked’ seams and areas from the total historical record and not only from the surviving mine plans. Secondly, insufficient subsidence incidents were discovered in the Pilot Area to carry out meaningful back analysis.The study was extended to collect all readily available records of subsidence incidents throughout the Coalfield. A total of 388 were traced, mainly dating from 1960. About threequarters were collapses through superficial materials and were either close to the outcrop or above mine entries, the remaining 25% propagated to the ground surface through rock. The upper limit of migration was typically 8 times the extracted height where the dip was shallow, incrasing to as much as 18 times for steep dips. Selected grout contracts and opencast mining sites were also examined to gain information on the present condition of old workings and to study the ‘reputations’ of the various seams for voids.The results of the coalfield study were applied to the Pilot Area to produce a 1:10 000 scale Development Advice Map, ‘Mining Subsidence for use by developers and planners’. The map is zoned to show areas where specialist advice is necessary to support a planning application and it also shows all mine entries traced by the desk study. The method of production is general for the South Wales Coalfield and further maps could be prepared, using the Coalfield Study, quickly and cheaply.

Behavior of Building Occupants in Earthquakes

1985 ◽  
Vol 1 (2) ◽  
pp. 271-283 ◽  
Author(s):  
Michael E. Durkin
Keyword(s):  
Seismic Performance ◽  
Earthquake Hazard ◽  
Research Area ◽  
Hazard Reduction ◽  
Realistic Appraisal

To be truly effective, earthquake hazard reduction measures must be based on a realistic appraisal of occupants' capabilities and actions during earthquakes. Studies suggest that many overly general beliefs about appropriate response can endanger rather than protect building occupants. We need to analyze occupant actions with respect to hazards posed by the seismic performance of specific building types. This paper will review the findings of recent U.S. studies, discuss the applicability of research from abroad, and summarize requirements for continued progress in this vital research area.

Geomorphic Indexes of Tectonic Activity Relative through The Analysis Quantitative in Cisanggarung Watershed, Kuningan District, West Java, Indonesia

2021 ◽  
pp. 367-375
Author(s):  
Ajeng Sekarkirana Pramesti Kameswara ◽  
Nana Sulaksana ◽  
Murni Sulastri ◽  
P. P. Raditya R.
Keyword(s):  
Activity Index ◽  
Shape Index ◽  
Research Area ◽  
Tectonic Activity ◽  
West Java ◽  
High Class ◽  
Watershed Area ◽  
Average Value ◽  
Active Tectonic ◽  
Class 1

The research area is very interesting to study to determine the characterization of the active tectonic influence of the Cisanggarung watershed, West Java. The research area is in Kuningan Regency, West Java. The purpose of this study was to determine the Relative Tectonic Activity Index (Iatr) in the Cisanggarung Watershed. Through the method approach used to identify the Relative Tectonic Activity Index (Iatr) using geomorphic indexes, watershed asymmetry factors (Af), watershed shape index (Bs), valley width, and height valley ratio (Vf), and mountainous face sinusitis (Smf). The Iatr research area is divided into 4 classes: Class 1 (very high), class 2 (high), class 3 (medium), and class 4 (low). Iatr distribution in 14 sub-watersheds covering an area of 286.24 km2 is Class 1 around 14.44% of the watershed area (41.35 km2) which is located in sub-watershed 1, with Smf values 1.157, Vf 0.3, Af 72.15, and Bs 4.3. Class 2 around 28.67% of the watershed area (82.09 km2) is located in sub-watershed 14, with Smf values 1.26, Vf 0.77, Af 15.69, Bs 1.01. Class 3 around 54.16% of the watershed area (155.03 km2) is located in sub-watersheds 2, 3, 6, 7, 8, 10, 11, 12, with an average value of Smf 2, Vf 1.54, Af 51.77, Bs 1.75, and Class 4 about 2.71% of the watershed area (7.76 km2) is located in sub- watersheds 4, 5, 9, 13, with an average value of Smf 2.25, Vf 8.18, Af 55.2, Bs 1.65. The results of the morphometric analysis indicated that the study area was mostly affected by tectonics and erosion.

Microearthquakes in the Tihamat-Asir region of Saudi Arabia

1980 ◽  
Vol 70 (6) ◽  
pp. 2291-2293
Author(s):  
H. M. Merghelani ◽  
S. K. Gallanthine
Keyword(s):  
Saudi Arabia ◽  
Continental Crust ◽  
Red Sea ◽  
Fault Plane ◽  
Seismic Refraction ◽  
Earthquake Hazard ◽  
Tectonic Activity ◽  
Fault Plane Solutions ◽  
High Level ◽  
Asir Region

abstract During the course of a seismic refraction investigation in Saudi Arabia, an unexpected high level of microearthquake activity was detected near the border of the Red Sea and near the transition from oceanic to continental crust. The data is not adequate to determine fault plane solutions nor to relate the earthquakes to specific structures, but the existence of microearthquakes at this location suggest that there is a significant level of tectonic activity at a point 200 km from an axial trough of the Red Sea. These data, combined with other recent geological observations, may be an important clue to the understanding of continental rifting. The data suggest the need for a more thorough investigation of the earthquake hazard along the shores of the Red Sea.

scholarly journals U–Pb dating of middle Eocene–Pliocene multiple tectonic pulses in the Alpine foreland

Solid Earth ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 2539-2551
Author(s):  
Luca Smeraglia ◽  
Nathan Looser ◽  
Olivier Fabbri ◽  
Flavien Choulet ◽  
Marcel Guillong ◽  
...  
Keyword(s):  
Middle Eocene ◽  
Regional Scale ◽  
Earthquake Hazard ◽  
Late Eocene ◽  
Passive Margin ◽  
Tectonic Activity ◽  
Thrust Belt ◽  
Fold And Thrust Belt ◽  
Earthquake Hazard Assessment ◽  
Alpine Foreland

Abstract. Foreland fold-and-thrust belts (FTBs) record long-lived tectono-sedimentary activity, from passive margin sedimentation, flexuring, and further evolution into wedge accretion ahead of an advancing orogen. Therefore, dating fault activity is fundamental for plate movement reconstruction, resource exploration, and earthquake hazard assessment. Here, we report U–Pb ages of syn-tectonic calcite mineralizations from four thrusts and three tear faults sampled at the regional scale across the Jura fold-and-thrust belt in the northwestern Alpine foreland (eastern France). Three regional tectonic phases are recognized in the middle Eocene–Pliocene interval: (1) pre-orogenic faulting at 48.4±1.5 and 44.7±2.6 Ma associated with the far-field effect of the Alpine or Pyrenean compression, (2) syn-orogenic thrusting at 11.4±1.1, 10.6±0.5, 9.7±1.4, 9.6±0.3, and 7.5±1.1 Ma associated with the formation of the Jura fold-and-thrust belt with possible in-sequence thrust propagation, and (3) syn-orogenic tear faulting at 10.5±0.4, 9.1±6.5, 5.7±4.7, and at 4.8±1.7 Ma including the reactivation of a pre-orogenic fault at 3.9±2.9 Ma. Previously unknown faulting events at 48.4±1.5 and 44.7±2.6 Ma predate the reported late Eocene age for tectonic activity onset in the Alpine foreland by ∼10 Myr. In addition, we date the previously inferred reactivation of pre-orogenic strike-slip faults as tear faults during Jura imbrication. The U–Pb ages document a minimal time frame for the evolution of the Jura FTB wedge by possible in-sequence thrust imbrication above the low-friction basal decollement consisting of evaporites.

scholarly journals Earthquake Disaster Mitigation Mapping By Modeling of Land Layer and Site Effect Zone in The Kota Baru of South Lampung

2019 ◽  
Vol 8 (1) ◽  
pp. 53-67 ◽  
Author(s):  
Nandi Haerudin ◽  
Rustadi Rustadi ◽  
Helmy Fitriawan ◽  
Deassy Siska ◽  
Muchammad Farid
Keyword(s):  
Site Effect ◽  
Dominant Frequency ◽  
Soil Characteristics ◽  
Disaster Mitigation ◽  
Tectonic Activity ◽  
Earthquake Risk ◽  
Sediment Thickness ◽  
Layer Model ◽  
History Of ◽  
The City

Kota Baru is the satellite city of Bandar Lampung. The city is prepared for the expansion of the city of Bandar Lampung. Zonation map of earthquake risk is required for Kota Baru due to its location within the reach of earthquake energy of Semangko subduction fault. In this study, we model the earthquake-prone zone map based on the soil characteristics (site effect) combined with the underground layer model to get a detailed description of the horizontal and vertical soil character. The microtremor method is performed to obtain the zonation effect mapping. Whereas, the ground layer modeling is obtained using the geoelectrical method. The modeling results show that the study area is far from tectonic activity based on the history of past earthquake events. However, this area has a large sediment thickness and has a low dominant frequency value, so it is an area that is vulnerable to earthquakes

scholarly journals Geophysical and geotechnical factors in urban planing: Bursa (Nilüfer, Osmangazi, and Yildirim) cases

2020 ◽  
Author(s):  
Ferhat Özçep ◽  
Guldane Boyraz ◽  
Okan Tezel ◽  
Hakan Alp ◽  
Nuray Alpaslan ◽  
...  
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Earthquake Hazard ◽  
Cyclic Stress ◽  
Soil Liquefaction ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Earthquake Motion ◽  
Potential Index ◽  
Earthquake Hazard Analysis

Abstract. The study area covers the Central of Bursa, Osmangazi, Yildirim, Gürsü, Kestel and Nilüfer District boundaries in Bursa. The seismic process deals with the occurrence of an earthquake event and the process of wave propagation from the source to the site. Local amplification caused by surficial soft soils is a significant factor in destructive earthquake motion. In the first phase of this study, it is investigated the ground motion level and soil amplifications for Bursa city. For his aim, probabilistic and deterministic earthquake hazard analysis (including acceleration estimations) will be carried out for the region. Local amplification caused by surficial soft soils is a significant factor in destructive earthquake motion. In the first phase of this study, it is investigated the ground motion level and soil acharacterization for the region. For his aim, probabilistic earthquake hazard analysis (including acceleration estimations) was carried out for the region. Then, soil shear wave velocities were estimated from data obtained by MASW measurements. Soil liquefaction is a natural event in which the strength and stiffness of a soil are reduced by earthquake vibrations or other dynamic loadings. As it is known, liquefaction occurs in saturated soils, that is, soils in which the space between individual particles is completely filled with water. One of liquefaction evaluation methods is based on the cyclic stress approach. In this method, a safety factor is defined as CRR/CSR. CRR is a cyclic resistance ratio that represents soil liquefaction susceptibility, and CSR is the cyclic stress ratio that represents the earthquake effect. In the second phase of this study, possible soil potential index (PL) and ground induced settlements were estimated by using Isihara ve Yoshimine (1990) approach. All results on liquefaction potential index (Pl), liquefaction induced settlements and soil shear wave velocities in Bursa (Turkey) City were compared with each other. Finally, a seismic microzonation map was prepared by the integration of geophysical and geotechnical data for urban planning purposes.

scholarly journals Determination of Recent Movements of Lithosphere in Regions with Chemogenic Sediments on the Surface in the Dinarides Region

2014 ◽  
Vol 96 (1) ◽  
pp. 20-26
Author(s):  
Almin Đapo ◽  
Boško Pribičević ◽  
Lidija Špiranec
Keyword(s):  
Carbonate Rocks ◽  
Ground Surface ◽  
Tectonic Activity ◽  
Surrounding Area ◽  
Isostatic Equilibrium ◽  
Tectonic Movements ◽  
Chemical Sediments ◽  
Carbonate Deposits ◽  
Significant Mass

Abstract In the area of carbonate or karst Dinarides, besides the dominant carbonate rocks and subordinate clastics, in more places more significant mass of chemical sediments can be found, represented by gypsum and anhydrite. As chemical sediments are specifically lighter than overlying rocks, they have been, during the long geological history, trying to achieve isostatic equilibrium, or get out on the ground surface. In recent times, in areas with chemical sediments, a larger tectonic activity is noted than in the wider environment. This is certainly reflected in increased vertical and tangential displacements along major faults in relation to the surrounding area, which are built mainly of carbonate deposits. Determining the amount of movement of diapiric bodies, as absolute and relative, using the most modern surveying methods, precisely would assist the understanding of the tectonic movements and recent structural relations in a wider area

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