Seismic hazard evaluation in Anjar city area of western India: Microtremor array measurement |
| |
| Institution: | 1. Institute of Geotechnical Engineering, Dalian University of Technology, Dalian 116024, China;2. Institute of Geotechnical Engineering, The University of Tokushima, Tokushima 770-8506, Japan;1. Politecnico di Torino, Torino, Italy;2. French Alternative Energies and Atomic Energy Commission (CEA), Cadarache, Saint-Paul-lez-Durance, France;3. Univ. Grenoble Alpes/CNRS/IRD/IFSTTAR, ISTerre, F-38000 Grenoble, France;4. University of Texas, Austin, TX, USA;5. University of Potsdam, Potsdam, Germany;6. EdF, France;7. Monash University, Melbourne, Australia;8. INGV, L’Aquila, Italy;9. Black Forrest Observatory, Germany;10. Geometrics, USA;11. Geovision, USA;12. Kyoto University, Japan;13. CEREMA, Direction Territoriale Méditerranée, Nice, France;14. Swiss Seismological Service, ETHZ, Zurich, Switzerland;15. Tokyo Institute of Technology, Japan;1. Institute of Seismological Research, Gandhinagar, Gujarat, India;2. Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan |
| |
| Abstract: | In western India during the Bhuj earthquake (Mw 7.6) on January 26, 2001, the Anjar City at ~30 km southwest of Bhuj experienced three types of damage scenario: severely damaged, less damaged and non-damaged. Similar damage patterns were also observed for the 1819 (Mw 7.8) and the 1956 (Mw 6.0) earthquakes. Microtremor array measurements were conducted in and around the Anjar city to examine the strength of soil structures and damage pattern. Significant differences are observed in frequencies and amplitudes in horizontal-to-vertical spectral ratio (HVSR) using microtremor measurements. The severely- damaged site shows two peak amplitudes: 2.8 at 1.2 Hz; and 4.0 at 8.0 Hz. The less-damaged site also shows two amplitudes: 2.5 and 2.1 at 1.4 Hz; and 2.0 Hz, respectively. The non-damaged site, on the other hand, shows that the HVSR curves become almost flatter. Similar results for three types of damage scenario based on analyses of earthquake records are also observed for the study area. The microtremor array measurements has revealed shear wave velocity Vs≥400 m/s at 18 m depth in the non-damaged, at 40 m in the less-damaged and at 60 m depth in the severely-damaged sites. The site amplitudes and the Vs values show a good correlation with the soil characteristics and damage pattern, suggesting that strength of soil layers at varying depths is a dictating factor for the estimate of the earthquake risk evaluation of the area under study. |
| |
| Keywords: | Damage scenario Earthquake records Microtremor array measurement Shear wave velocity Site effects |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
