Archaeoseismology and Palaeoseismology in the Alpine ... - Tierra

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The attenuation of the recorded seismic data is shown in Fig. 3. It is clear that the recorded ground motions gives much higher peak ground acceleration values, than what is predicted by the empirical attenuation relationships. The largest ground motions were recorded by the three near fault stations Wolong, Qingping and Baijiao, which recorded maximum values of 957.7, 824.1 and 633.1 cm/s 2 , respectively (Li et al., 2008b). The attenuation of the simulated ground motions found in the present study is shown as the lower graph in Fig. 3. From this it can be seen, that the simulated peak acceleration values are comparable to those recorded during the earthquake. Fig.4: Top: Simulated Pseudoacceleration response spectra for the three stations Qingping, Baijiao and Wolong. The two horizontal components are shown (see legend for specifications). Bottom: Acceleration response spectra obtained from Wolong station in Wenchuan during the mainshock of 12 May 2008, form Li et al., (2008a). Fig. 4 shows the pseudoacceleration response spectra, from the ground motion simulation, for the stations in Wolong, Qingping and Baijiao (see Fig. 2 for locations). Tthe predominant periods of the simulated ground motions are between 0.1s and 1s. The simulation results are well in agreement with Li et al. (2008a), which estimate the predominant spectral acceleration to be distributed between periods of 0.1s to 0.6s (see the lower graph in Fig. 4) and the ground motion simulation therefore reproduces the frequency content of the seismic waves to a very large extent. STRONG GROUND SHAKING AND DAMAGE ON BUILDINGS The affected area suffered severe destruction during the earthquake. The economic losses due to the event are estimated to be 86 billion USD (USGS). The city of Hanwang is located along the fault, approximately 90km NE of the epicentre and had 70,000 inhabitants before 1 st INQUA‐IGCP‐567 International Workshop on Earthquake Archaeology and Palaeoseismology 14 the earthquake. During the earthquake 4,500 have lost their lives. In an area of approximately 3km 2 in the central part of Hanwang, 90‐95% of the buildings were totally or partially collapsed, resulting in a large uninhabitable area. The picture in Fig. 5 is taken in the area of almost total collapse. The typical buildings in this area are residential buildings of 4‐5 stories. In the foreground, rubble from totally collapsed buildings is visible, whereas the buildings in the background are still standing. In this area the adobe structures have almost completely collapsed, whereas the more recent reinforced concrete structures seem to have been able to withstand the strong ground shaking. Fig.5: Picture taken in Hanwang, inside the 3km 2 area of almost total collapse. Using a simple empirical relation for fundamental periods of structures (Kramer, 1996), for the typical structures dominating the area in Hanwang, the predominant periods are estimated to be 0.16‐0.21s for two story buildings. The first floor is usually used as a shop and the second floor as living area. For five‐story apartment buildings on the other hand, the fundamental frequency is estimated to be 0.47‐0.56s. Comparing the fundamental periods of the structures in the area to the predominant periods of the seismic signals coincide to a large extent, which is the reason why these buildings have not been able to withstand the ground motion experienced in the area. Furthermore, the older buildings suffered from an insufficient design code, since there have been many revisions of the seismic design code for buildings in China during time, latest in 2001 (Zhao et al., in press). The buildings which are still standing in the area (e.g. like the buildings to the left in the picture) were under construction at the time of the earthquake, and they are assumed to be designed after the latest adequate seismic design code. CONCLUSIONS In the present study we have used a hybrid broadband technique for modeling ground motions caused by the May 12, 2008 Wenchuan earthquake. The following conclusions can be drawn from the simulation results: - The ground motions experienced during the May 12 Wenchuan earthquake were reproduced, and values similar to those recorded on the near field stations in the area, with maximum bedrock ground motions in the order of 850 cm/s2 (PGA) and 200 cm/s (PGV), were obtained. - The values of the simulated PGA are higher than predicted commonly by empirical attenuation
elations. However, the attenuation of our simulated ground motions agrees very well with the recorded seismic data from the area. - The predominant periods of the pseudoacceleration response spectra corresponds to predominant periods estimated from the seismic data. - The predominant periods of the seismic signal corresponded to the fundamental periods of the structures in the area, causing total or partial collapse. In general the hybrid broadband simulation technique has proven to be a powerful tool for simulating realistic and reasonable ground motions in this retrospect study. The method is therefore useful for predictive studies as long as realistic input models constructed with geological and paleoseismic data are applied. Acknowledgements: We would like to thank the Earthquake Administration of Sichuan Province, Sichuan Provincial Department of Construction and Sichuan Association for Science & Technology who co‐sponsored the post‐conference field trip of the 14th World Conference on Earthquake Engineering to the Wenchuan Earthquake Area. We are grateful to the staff from China Earthquake Administration, Earthquake Administration of Sichuan Province, China Southwest Architectural Design and Institute Corp. Ltd., Sichuan Provincial Institute of Architectural Design, Sichuan Association for Science and Technology, Sichuan Provincial People’s Hospital and the translators which made this trip possible. References Boore, D.M., 1983, Stocastic simulation of high‐frequency ground motions based on seismological models of the radiated spectra: Bulletin of the Seismological Society of America, v. 73, p. 1865‐1894. Bouchon, M., 1981, A simple method to calculate Green's functions for elastic layered media: Bulletin of the Seismological Society of America, v. 71, p. 959‐971. Fukushima, Y., and Tanaka, T., 1990, A new attenuation relation for peak horizontal acceleration of strong earthquake ground motions in Japan: Bulletin of Seismological Society of America, v. 80, p. 27. Irikura, K., 1986, Prediction of strong acceleration motion using empirical Green's functions, Proc. 7th Japan Earthquake Symp.: Japan, p. 151‐156. 1 st INQUA‐IGCP‐567 International Workshop on Earthquake Archaeology and Palaeoseismology 15 Ji, C., and Hayes, G., 2008, Source model of the May 12th 2008 Wenchuan earthquake. Available at: http://earthquake.usgs.gov/eqcenter/eqarchives/poster/2008 /20080512.php, Volume 2008, USGS. Koketsu, K., Yokota, Y., Ghasemi, H., Hikima, K., Miyake, H., and Wang, Z., 2009, Source Process and Ground Motions of the 2008 Wenchuan Earthquake: Investigation report of the 2008 Wenchuan Earthquake, China, Grant‐in‐Aid for Special Purposes of 2008, MEXT, . Kramer, S.L., 1996, Geotechnical Earthquake Engineering: Upper Sadle River, New Jersey, Prentice Hall. Li, X., Zhou, Z., Huang, M., Wen, R., Yu, H., Lu, D., Zhou, Y., and Cui, J., 2008a, Preliminary Analysis of Strong‐Motion Recordings from the Magnitude 8.0 Wenchuan, China, Earthquake of 12 May 2008: Seismological Research Letters, v. 79, p. 11. Li, X., Zhou, Z., Yu, H., Wen, R., Lu, D., Huang, M., Zhou, Y., and Cu, J., 2008b, Strong motion observations and recordings from the great Wenchuan Earthquake: Earthquake Engineering and Engineering Vibration, v. 7, p. 12. Nishimura, N., and Yagi, Y., 2008, Rupture Process for May 12, 2008 Sichuan Earthquake (Ver. 2), http://www.geol.tsukuba.ac.jp/~nisimura/20080512/, Volume 2008: Ibaraki, Japan University of Tsukuba. Pulido, N., and Kubo, T., 2004, Near‐fault strong motion complexity of the 2000 Tottori earthquake (Japan) from a broadband source asperity model: Tectonophysics, v. 390, p. 177‐192. Pulido, N., Ojeda, A., Atakan, A., and Kubo, T., 2004, Strong ground motion estimation in the Sea of Marmara region (Turkey) based on a scenario earthquake: Tectonophysics, v. 391, p. 357‐374. Sadigh, K., Chang, C.‐Y., Egan, J.A., Makdisi, F., and Youngs, R.R., 1997, Attenuation Relationships for Shallow Crustal Earthquakes Based on California Strong Motion Data: Seismological Research Letters, v. 68, p. 10. Sørensen, M.B., Atakan, K., and Pulido, N., 2007, Simulated Strong Ground Motions for the Great M 9.3 Sumatra‐ Andaman Earthquake of 26 December 2004: Bulletin of the Seismological Society of America, v. 97, p. S139‐151. USGS, Magnitude 7.9 – Eastern Sichuan, China. Webpage, last accessed July 1, 2009. http://earthquake.usgs.gov/eqcenter/eqinthenews/2008/us2 008ryan/#summary. Wang, S.Y., Yu, Y.X., Gao, A.J., and Yan, X.J., 2000, Development of attenuation relations for ground motion in China: Earthquake Research in China, v. 16, p. 8. Zhao, B., Taucer, F., and Rossetto, T., 2009, Field investigation on the performance of building structures during the 12 May 2008 Wenchuan earthquake in China: Engineering Structures, v. In press.
Page 1: Abstracts Volume Archaeoseismology
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Page 9 and 10: the importance of performing absolu
Page 11 and 12: indicative of strike‐slip faultin
Page 13 and 14: DISCUSSION Based on detailed field
Page 15: Table 1: Source parameters used in
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Page 23 and 24: The tumulus initial morphology show
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Page 31 and 32: Nevertheless the lack of research,
Page 33 and 34: earthquake. In uncertain cases, as
Page 35 and 36: The site reconnaissance successfull
Page 43 and 44: Table 1: Surface faulting extent re
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Page 57 and 58: RISK ANALYSIS The created hazard ma
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Page 61 and 62: CONCLUSIONS From the palaeostress a
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1 st INQUA‐IGCP‐567 Internation
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however, the massive 1995 earthquak
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mapped on the slopes above Qiryat
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interpreted as either an expression
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The Shepran Cave is located on the
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properties. The mean value of speci
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excavated a deep trench, thus provi
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Fig. 8: Seismic ground shaking may
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elevant qualitative criteria are po
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CONCLUDING REMARKS The exposed exam
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produced by significantly different
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It is possible that a portion of th
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In addition, the Database of histor
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were published by IGME (1983) and E
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The city collapsed and it was aband
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Fig. 4: Slipped lintel in a window
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to overcome shear resistance and in
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Newmark, N.M. (1965). Effects of ea
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associated with various tsunamis (<
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this method, the magnitude of the e
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etween pieces. Fragments have not f
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on the exact date of the earthquake
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THE ARCHAEOLOGICAL ZONE COLOGNE Aft
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affecting the Alcázar was about 50
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archaeoseismology could instead bec
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In the area later occupied by Vilni
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Fig. 2: Assemblage of landforms ass
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Fig. 8: Data and regression for mag
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Fig. 3: Relationships among magnitu
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CONCLUSIONS 1. Spatial distribution
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The stratigraphic sequence (Fig. 4)
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especially in the zones of hanging
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interpretations are based on relati
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Fig. 5: Gray‐scale value laser im
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(~40 cm), F‐ rotated building str
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Index 1 st INQUA‐IGCP‐567 Inter
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