Activity and distribution of geohazards induced by the Lushan earthquake, April 20, 2013
Tóm tắt
An Ms7.0 earthquake, focal depth 13 km, struck Lushan on April 20, 2013, caused 196 deaths and 21 missing, 13,484 injuries, and affected more than two million people. A field investigation was taken immediately after the quake, and the induced hazards were analyzed in comparison with the Wenchuan earthquake. We have identified 1,460 landslides and avalanches and four dammed lakes, which were generally small and concentrated on high elevation. Avalanches and rockfalls developed in cliffs and steep slopes of hard rocks, including Jinjixia of Baosheng Town and Dayanxia of Shuangshi Town, Lushan, and the K317 section the Xiaoguanzi section north to Lingguan Town along the provincial highway S210. Landslides were relatively less, mainly in moderate and small scales, developing in sandstone, shale, and loose colluviums. Only one single large landslide was observed to turn into debris slide-flow. Dammed lakes were formed by avalanches and landslides, all in small size and of low danger degree. The earthquake-induced hazards distributed in belt on the hanging wall along the faults, and their major controlling factors include tectonics, lithology, structure surface, and landform. More than 99 % landslides were within 30 km to the epicenter, and 678 within 10 km, accounting for 46 % of the total; about 50 % landslides were distributed on slopes between 35° and 55°, and 11 % on slope exceeding 75°; 60 % on slopes at the altitudes between 1,000 and 1,500 m, 77 % on slopes between 900 and 1,500 m; and 24 and 62 % in hard rocks and section between hard and soft rocks, respectively. Compared with the case of Wenchuan earthquake, both the number and extension of landslides and avalanches in Lushan earthquake-affected area are much smaller, only 5.53 % in number and 0.57 % in area. The earthquake has increased the instability of slope and potentiality of landslide and debris flow. Accordingly, the active period is expected to be relatively short comparing with that in Wenchuan earthquake-hit area. However, the insidious and concealed hazards bring difficulty for risk investigation.
Tài liệu tham khảo
Aleotti P, Chowdhury R (1999) Landslide hazard assessment: summary review and new perspectives. Bull Eng Geol Environ 58(1):21–44
Chen XQ, Cui P, Cheng ZL, You Y, Zhang X, He S, Dang C (2008) Emergency risk assessment of dammed lakes caused by the Wenchuan earthquake on May 12, 2008. Earth Sci Front 15(4):244–249
Chen XQ, Cui P, Li Y, Gao Q, Zhao WY (2010) Mountain hazard induced by Wenchuan earthquake and its long-term development trends of Ganxi Gully, Beichuan. J Sichuan Univ (Eng Sci Edn), S1
Chigira M, Wu X, Inokuchi T, Wang G (2010) Landslides induced by the 2008 Wenchuan earthquake, Sichuan, China. Geomorphology 118(3):225–238
China Earthquake Administration (2013a) The 20 April Lushan earthquake. http://www.cea.gov.cn/publish/dizhenj/468/553/100342/index.html. Apr 20, 2013 (in Chinese)
China Earthquake Administration (2013b) Lushan earthquake field emergency team of China Earthquake Administration complete the seismic tectonic environment and seismogenic structure analysis. http://www.cea.gov.cn/publish/dizhenj/468/553. Apr 27, 2013 (in Chinese)
Cui P, Zhu YY, Han YS, Chen XQ, Zhuang JQ (2009) The 12 May Wenchuan earthquake-induced landslide lakes: distribution and preliminary risk evaluation. Landslides 6(3):209–223
Cui P, Chen XQ, Zhu YY, Su FH, Wei FQ, Han YS, Zhuang JQ (2011a) The Wenchuan earthquake (May 12, 2008), Sichuan province, China, and resulting geohazards. Nat Hazards 56(1):19–36
Cui P, He S, Yao L et al (2011b) Formation mechanism and risk control of mountain hazards induced by Wenchuan earthquake. Science Press, Beijing (in Chinese)
Gorum T, Fan X, van Westen CJ, Huang RQ, Xu Q, Tang C, Wang G (2011) Distribution pattern of earthquake-induced landslides triggered by the 12 May 2008 Wenchuan earthquake. Geomorphology 133(3):152–167
Higaki D, Abe S (2013) Classification of the geomorphology, geology and movement types of earthquake landslides. In: Earthquake-induced landslides (pp 37–44). Springer, Berlin, Heidelberg
Keefer DK (2000) Statistical analysis of an earthquake-induced landslide distribution—the 1989 Loma Prieta, California event. Eng Geol 58(3):231–249
Li HB, Fu XF, Van Der Woerd J, Si JL, Wang ZX, Hou LW, Tapponnier P (2008) Co-seismic surface rupture and dextral-slip oblique thrusting of the Ms 8.0 Wenchuan earthquake. Acta Geol Sinica 82(12):1623–1643
Liu F, Li D, Liu D, Li J, Tang H (2012) Tectonic analysis of Wenchuan earthquake collapse and landslide development characteristics and spatial distribution law. In: Advances in electric and electronics (pp 757–765). Springer, Berlin, Heidelberg
Meunier P, Hovius N, Haines JA (2008) Topographic site effects and the location of earthquake induced landslides. Earth Planet Sci Lett 275(3):221–232
Ministry of Construction of the People’s Republic of China, General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China (2009) Code for investigation of geotechnical engineering (GB 50021-2001). China Planning Press
Owen LA, Kamp U, Khattak GA, Harp EL, Keefer DK, Bauer MA (2008) Landslides triggered by the 8 October 2005 Kashmir earthquake. Geomorphology 94(1):1–9
Xu J, Zhang S, Guo H et al (1984) Prevention and control of debris flows of Luwang gully and Ganxi gully in Ya’an city, Sichuan province. Mount Res 2(2):117–124 (in Chinese)
Yin Y, Cheng Y, Wang J et al (2011) Remote sensing research on Daguangbao gigantic rock-slide triggered by Wenchuan earthquake. J Eng Geol 19(5):674–684 (in Chinese)
Zhang Y, Xu LS, Chen YT (2013) Rupture process of the Lushan 4.20 earthquake and preliminary analysis on the disaster-causing mechanism. Chin J Geophys Chin Edn 56(4):1408–1411
Zhang JQ, Cui P, Ge YG, Xiang LZ (2012) Susceptibility and risk assessment of earthquake-induced landslides based on landslide response units. Environ Earth Sci 65(4):1037–1047
Zhao CP, Zhou LQ, Chen ZL (2013) Source rupture process of Lushan MS7.0 earthquake, Sichuan, China and its tectonic implications. Chin Sci Bull 58:3444–3450. doi:10.1007/s11434-013-6017-6