scholarly journals ESTIMATION OF SUBSURFACE STRUCTURE BASED ON MICROTREMOR, BORE HOLE OBSERVATIONS AND STOCHASTIC STRONG GROUND MOTION SIMULATIONS IN PALU CITY, CENTRAL SULAWESI, INDONESIA: A VALIDATION AND SENSITIVITY STUDY ON THE 23 JANUARY 2005 (PALU) EARTHQUAKE

2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Pyi Soe Thein ◽  
Subagyo Pramumijoyo ◽  
Wahyu Wilopo ◽  
Agung Setianto ◽  
Kirbani Sri Brotopuspito ◽  
...  
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Strong Ground Motion ◽  
Soil Condition ◽  
Fault System ◽  
Earthquake Ground Motion ◽  
Subsurface Structure ◽  
Ground Acceleration ◽  
Central Sulawesi ◽  
Strong Ground

In this study, we investigated the subsurface structure and strong ground motion parameters for Palu City. One of the major structures in Central Sulawesi is the Palu-Koro Fault system. Several powerful earthquakes have struck along the Palu-Koro Fault during recent years, one of the largest of which was an M 6.3 event that occurred on January 23, 2005 and caused several casualties. Following the event, we conducted a microtremor survey to estimate the shaking intensity distribution during the earthquake. From this survey we produced a map of the peak ground acceleration, velocity and ground shear strain in Palu City. We performed single observations of microtremors at 151 sites in Palu City. The results enabled us to estimate the site-dependent shaking characteristics of earthquake ground motion. We also conducted 8-site microtremor array investigation to gain a representative determination of the soil condition of subsurface structures in Palu. From the dispersion curve of array observations, the central business district of Palu corresponds to relatively soil condition with Vs ≤ 300 m/s, the predominant periods due to horizontal vertical ratios (HVSRs) are in the range of 0.4 to 1.8 s and the resonant frequency are in the range of 0.7 to 3.3 Hz. Three boreholes were throughout the basin especially in Palu area to evaluate the geotechnical properties of subsurface soil layers. The depths are varying from 1 m to 30 m. Strong ground motions of the Palu area were predicted based on the empirical stochastic green’s function method. Peak ground acceleration and peak ground velocity becomes more than 0.04 g and 30 kine in some areas, which causes severe damage for buildings in high probability. Keywords: Palu-Koro fault, microtremor, bore holes, peak ground acceleration and velocity.

scholarly journals Relationships between macroseismic intensity and peak ground acceleration and velocity for the Vrancea (Romania) subcrustal earthquakes

2021 ◽  
Vol 64 (4) ◽  
pp. SE432
Author(s):  
Iren-Adelina Moldovan ◽  
Angela Petruta Constantin ◽  
Raluca Partheniu ◽  
Bogdan Grecu ◽  
Constantin Ionescu
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Strong Ground Motion ◽  
Empirical Relationship ◽  
Macroseismic Intensity ◽  
Ground Acceleration ◽  
Ground Motion Parameters ◽  
Motion Parameters ◽  
Subcrustal Earthquakes ◽  
Strong Ground

The goal of this paper is to develop a new empirical relationship between observed macroseismic intensity and strong ground motion parameters such as peak ground acceleration (PGA) and velocity (PGV) for the Vrancea subcrustal earthquakes. The recent subcrustal earthquakes provide valuable data to examine these relationships for Vrancea seismogenic region. This region is one of the most active seismic zones in Europe and it is well-known for the strong subcrustal earthquakes. We examine the correlation between the strong ground-motion records and the observed intensities for major and moderate earthquakes with Mw ≥ 5.4 and epicentral intensity in the range VI to IX MSK degrees that occurred in Vrancea zone in the period 1977-2009. The empirical relationships between maximum intensity and ground parameters obtained and published by various authors have shown that these parameters do not always show a one-to-one correspondence, and the errors associated with the intensity estimation from PGA/PGV are sometimes +/-2 MSK degree. In the present study, the relation between macroseismic intensity and PGA/PGV will be given both as a mathematical equation, but also as corresponding ground motion intervals. Because of the intensity data spreading and errors related to mathematical approximations, it is necessary to systematically monitor not only the acceleration and velocity but also all the other ground motion parameters. The mathematical relation between these parameters might be used for the rapid assessment of ground shaking severity and potential damages in the areas affected by the Vrancea earthquakes.

On strong ground motion estimates based on models of the radiated spectrum

1985 ◽  
Vol 75 (3) ◽  
pp. 641-649
Author(s):  
J. Enrique Luco
Keyword(s):  
Ground Motion ◽  
Stress Drop ◽  
Peak Ground Acceleration ◽  
Strong Ground Motion ◽  
Source Model ◽  
Spectral Model ◽  
Ground Acceleration ◽  
A Value ◽  
Strong Ground ◽  
Good Agreement

Abstract Estimates for peak ground acceleration and velocity were obtained by use of the approach of Hanks and McGuire (1981) and Boore (1983) for a model of the radiated spectrum corresponding to Brune's ω−2 source model modified by an exponentially decreasing function of frequency. This modification was suggested by the work of Anderson and Hough (1984) on spectral amplitudes. For this spectral model, it was found that it is not possible to determine a value for the stress drop parameter such that agreement with data is obtained for both peak accelerations and velocities. This finding contrasts with that of Boore (1983) who found good agreement with data by introducing an artificial cut-off frequency of 15 Hz.

scholarly journals Evaluation of strong ground motion for Yogyakarta depression area, Indonesia

2015 ◽  
Vol 2 (2) ◽  
Author(s):  
Myo Thant ◽  
Subagyo Pramumijoyo ◽  
Heru Hendrayana ◽  
Hiroshi Kawase ◽  
Agus Darmawan Adi
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Strong Ground Motion ◽  
Seismic Source ◽  
Probabilistic Seismic Hazard ◽  
Hazard Maps ◽  
Ground Acceleration ◽  
Seismic Hazard Maps ◽  
Strong Ground

The probabilistic seismic hazard maps are developed for Yogyakarta depression area. The earthquake catalog of ANSS (1970-2007) is taken into account with the complement of NEIC (USGS, 1973-2007) and the records of BMG (2000-2004). On the basis of seismicity of the area, tectonics and geological information, the seismic source zones are characterized for this area. The seismicity parameters of each seismic source are determined by applying the classical Gutenberg-Richter recurrence model, regarding the historical records. The attenuation relation for Yogyakarta depression area cannot be evaluated since the sufficient strong ground motion records are not available for this region. Therefore the attenuation relations which were developed for other territories as Europe and Japan are used for the present hazard calculation by validating, using the aftershocks records, modeling the peak ground acceleration maps for the recent event, 27 May, 2006, Yogyakarta earthquake inserting the damage area distribution pattern. The probabilistic seismic hazard maps are finally developed by using the McGuire (1976) EQRISK computer program by modifying for the present purpose. The seismic hazard maps expressed in term of peak ground acceleration are developed for the recurrence intervals of 10, 50, 100, 200 and 500 years

scholarly journals Earthquakes on the surface: earthquake location and area based on more than 14 500 ShakeMaps

2018 ◽  
Vol 18 (6) ◽  
pp. 1665-1679
Author(s):  
Stephanie Lackner
Keyword(s):  
Ground Motion ◽  
Strong Ground Motion ◽  
Earthquake Location ◽  
Primary Concern ◽  
Ground Acceleration ◽  
Ground Shaking ◽  
Geographic Context ◽  
The Social ◽  
Strong Ground

Abstract. Earthquake impact is an inherently interdisciplinary topic that receives attention from many disciplines. The natural hazard of strong ground motion is the reason why earthquakes are of interest to more than just seismologists. However, earthquake shaking data often receive too little attention by the general public and impact research in the social sciences. The vocabulary used to discuss earthquakes has mostly evolved within and for the discipline of seismology. Discussions on earthquakes outside of seismology thus often use suboptimal concepts that are not of primary concern. This study provides new theoretic concepts as well as novel quantitative data analysis based on shaking data. A dataset of relevant global earthquake ground shaking from 1960 to 2016 based on USGS ShakeMap data has been constructed and applied to the determination of past ground shaking worldwide. Two new definitions of earthquake location (the shaking center and the shaking centroid) based on ground motion parameters are introduced and compared to the epicenter. These definitions are intended to facilitate a translation of the concept of earthquake location from a seismology context to a geographic context. Furthermore, the first global quantitative analysis on the size of the area that is on average exposed to strong ground motion – measured by peak ground acceleration (PGA) – is provided.

The Loma Prieta earthquake, ground motion, and damage in Oakland, Treasure Island, and San Francisco

1991 ◽  
Vol 81 (5) ◽  
pp. 2019-2047
Author(s):  
Thomas C. Hanks ◽  
A. Gerald Brady
Keyword(s):  
Ground Motion ◽  
San Francisco ◽  
Strong Ground Motion ◽  
Strong Motion ◽  
Earthquake Ground Motion ◽  
Transverse Motion ◽  
Loma Prieta Earthquake ◽  
Loma Prieta ◽  
Treasure Island ◽  
Strong Ground

Abstract The basis of this study is the acceleration, velocity, and displacement wave-forms of the Loma Prieta earthquake (18 October 1989; M = 7.0) at two rock sites in San Francisco, a rock site on Yerba Buena Island, an artificial-fill site on Treasure Island, and three sites in Oakland underlain by thick sections of poorly consolidated Pleistocene sediments. The waveforms at the three rock sites display a strong coherence, as do the three sedimentary sites in Oakland. The duration of strong motion at the rock sites is very brief, suggestive of an unusually short source duration for an earthquake of this size, while the records in Oakland show strong amplification effects due to site geology. The S-wave group at Treasure Island is phase coherent with the Oakland records, but at somewhat diminished amplitudes, until the steps in acceleration at approximately 15 sec, apparently signaling the onset of liquefaction. All seven records clearly show shear-wave first motion opposite to that expected for the mainshock radiation pattern and peak amplitudes greater than expected for sites at these distances (95 ± 3 km) from an earthquake of this magnitude. While the association between these ground motion records and related damage patterns in nearby areas has been easily and eagerly accepted by seismological and engineering observers of them, we have had some difficulty in making such relationships quantitative or even just clear. The three Oakland records, from sites that form a nearly equilateral triangle about the Cypress Street viaduct collapse, are dominated by a long-period resonance (≃ 1 1/2-sec period) far removed from the natural frequency of the structure to transverse motion (2.5 Hz) or from high-frequency amplification bands observed in aftershock studies. A spectral ratio arbiter of this discrepancy confuses it further. The failure of the East Bay crossing of the San Francisco-Oakland Bay Bridge cannot be attributed to relative displacements of the abutments in Oakland and Yerba Buena Island, but the motions of the Bay Bridge causing failure remain unknown. The steps in acceleration at Treasure Island present unusual strong-motion accelerogram processing problems, and modeling suggests that the velocity and displacement waveforms are contaminated by a spurious response of the filtering operations to the acceleration steps. A variety of coincidences suggests that the Treasure island accelerogram is the most likely strong-motion surrogate for the filled areas of the Marina District, for which no mainshock records are available, but the relative contributions of bad ground, poor construction and truly strong ground motion to damage in the Marina District will never by known in any quantitative way. The principal lesson of all of this is that until a concerted effort is mounted to instrument ground and structures that are likely to fail during earthquakes, our understanding of the very complex relationships between strong ground motion and earthquake damage will, in general, remain rudimentary, imprecise, and vague.

Performance of a Rigid Frame Arch Bridge under Near-Fault Earthquake Ground Motion

2011 ◽  
Vol 250-253 ◽  
pp. 1869-1872 ◽  
Author(s):  
Yong Huang ◽  
Jun Jie Wang ◽  
De Yin Jin
Keyword(s):  
Wenchuan Earthquake ◽  
Ground Motion ◽  
Strong Ground Motion ◽  
Earthquake Ground Motion ◽  
Weak Links ◽  
Response Analysis ◽  
Arch Bridge ◽  
2008 Wenchuan Earthquake ◽  
Rigid Frame ◽  
Strong Ground

During May 12th 2008 Wenchuan earthquake with the magnitude of 8.0, a 4-span rigid frame arch bridge named as Xiaoyudong Bridge which situated close to the epicenter was hit by strong ground motion and was severely damaged. The earthquake response analysis of the bridge was made using FE software MIDAS based on recorded ground motion during the Wenchuan earthquake in this paper. The study showed that the main and minor arch legs on the both ends piers were weak links which may be damaged firstly under strong ground motion. The next damage at the pier with weakest horizontal stiffness is one of the important reasons causing the bridge collapsed. This paper will introduce our work on those respects and some drawn conclusions.

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