Distribution characteristics of geohazards induced by the Lushan Earthquake and their comparisons with the Wenchuan Earthquake

Abstract

The Lushan Earthquake induced a large number of geohazards. They are widely distributed and caused serious damages. The basic characteristics, formation mechanisms and typical cases of geohazards induced by Lushan Earthquake are described, and compares to the relationships of Lushan and Wenchuan earthquakes between geohazards and earthquake magnitude, geomorphology, slope angle, elevation and seismic intensity in the most affected areas in the article. (1) The numbers and volumes of landslides and rockslides differ significantly between the two earthquakes due to their differing magnitudes. The Lushan Earthquake is associated with fewer and smaller-magnitude geohazards, within the immediate area, which mainly consist of small-and medium-sized shallow landslides and rockslides, and occur on steep slopes and mountain valleys. The largest landslide induced by Lushan Earthquake is the Gangoutou Landslide debris flow with a residual volume of about 2.48×10⁶ m³. The most dangerous debris flow is at Lengmugou gulley in Baoxing County, which has similar geomorphological features and disaster modes as a previous disaster in Zhouqu County, Gansu Province. (2) Geohazards induced by the Lushan Earthquake show four mechanisms: cracking-rockslides-collision-scraping and then debris flows, cracking-rockslides, vibration-rainfall-rockslides-landslide and then debris flow, vibration-throwing or scrolling. (3) There are significant similarities and differences between the geohazards induced by these two earthquakes. The types of geohazards are the same but the volume, quantity and other factors differ: geohazards are concentrated on slope angles of 10°–40° in the Lushan Earthquake area, especially within 10°–20°, and at absolute elevation of 500–2 000 m above sea level (a.s.l.). Geohazards within the Wenchuan Earthquake area are concentrated on steeper slope angles of 30°–40° at higher absolute elevations of 1 500–2 000 m.s.l..

Keywords

Lushan Earthquake / Wenchuan Earthquake / geohazards / basic characteristics / comparison

References

[1] Burchfiel B C, Royden L H, van der Hilst R D, . A Geological and Geophysical Context for the Wenchuan Earthquake of 12 May 2008, Sichuan, People’s Republic of China. GSA Today, 2008, 18(7): 4-11.

[2] China Cartographic Publishing House The Atlas of Earthquake and Geological Disasters in Wenchuan, 2008 Beijing: Science Press, 1-20.

[3] China Earthquake Administration CEA Magnitude of the 12 May 2008 Wenchuan Earthquake and Aftershocks, 2008

[4] China Earthquake Administration CEA Special Report on “4·20” M _s 7.0 Magnitude Earthquake in Lushan, Sichuan Province, 2013

[5] China Seismic Information Center CSI The Earthquake Aftershocks Activity Analysis Report of Lushan on the 20 April 2013, 2013

[6] Cui P, Zhu Y Y, Han Y S, . The 12 May Wenchuan Earthquake-Induced Landslide Lakes: Distribution and Preliminary Risk Evaluation. Landslides, 2009, 6: 209-223.

[7] Deng Q D. Study on Active Tectonic in China. Geological Review, 1996, 42(4): 295-299.

[8] Fu X F, Hou L W, Li H B, . Coseismic Deformation of the M _s 8.0 Wenchuan Earthquake and Its Relationship with Geological Hazards. Acta Geologica Sinica, 2008, 82(12): 1733-1745.

[9] Gorum T, Fan X M, Westen C J, . Distribution Pattern of Earthquake-Induced Landslides Triggered by the 12 May 2008 Wenchuan Earthquake. Geomorphology, 2011, 133: 152-167.

[10] Hao K X, Si H, Fujiwara H, . Coseismic Surface-Ruptures and Crustal Deformations of the 2008 Wenchuan Earthquake M _w 7.9, China. Geophysical Research Letters, 2009, 36 L11303

[11] Huang R Q, Li W L. Analysis of the Geo-Hazards Triggered by the 12 May 2008 Wenchuan Earthquake, China. Bulletin of Engineering Geology and the Environment, 2009, 68: 363-371.

[12] Jin W, Tang L, Yang K, . Tectonic Evolution of the Middle Frontal Area of the Longmen Mountain Thrust Belt, Western Sichuan Basin, China. Acta Geologica Sinica, 2009, 83: 92-102.

[13] Kusky T M, Ghulam A, Wang L, . Focusing Seismic Energy along Faults through Time-Variable Rupture Modes: Wenchuan Earthquake, China. Journal of Earth Science, 2010, 21(6): 910-922.

[14] Land Resources Bureau of Ya’an The Geological Disasters Induced by “4·20” M _s 7.0 Magnitude Earthquake in Lushan, Sichuan Province, 2013

[15] Lin A, Ren Z, Jia D, . Co-Seismic Thrusting Rupture and Slip Distribution Produced by the 2008 M _w 7.9 Wenchuan Earthquake, China. Tectonophysics, 2009, 47: 203-215.

[16] Li H B, Wang Z X, Fu X F, . The Surface Rupture Zone Distribution of the Wenchuan Earthquake (M _s 8.0 ) Happened on May 12th, 2008. Geology in China, 2008, 35(5): 803-813.

[17] Li Q, Gao R, Wang H, . Deep Background of Wenchuan Earthquake and the Upper Crust Structure beneath the Longmen Shan and Adjacent Areas. Acta Geologica Sinica, 2009, 83: 733-739.

[18] Liu J G, Kusky T M. After the Quake: A First Hand Report on an International Field Excursion to Investigate the Aftermath of the China Earthquake. Earth Magazine (Formerly Geotimes), 2008, 10: 48-51.

[19] Sato H P, Harp E L. Interpretation of Earthquake-Induced Landslides Triggered by the 12 May 2008, M 7.9 Wenchuan Earthquake in the Beichuan Area, Sichuan Province, China Using Satellite Imagery and Google Earth. Landslides, 2009, 6: 153-159.

[20] Sun X Y, Zhou C H, Guo Z C, . Assessment and Analysis of Surface Secondary Disasters Induced by 5.12 Wenchuan Earthquake. Acta Geologica Sinica, 2010, 84(9): 1283-1291.

[21] Tang C, Zhu J, Qi X, . Landslides Induced by the Wenchuan Earthquake and the Subsequent Strong Rainfall Event: A Case Study in the Beichuan Area of China. Engineering Geology, 2011, 122: 22-33.

[22] Tang H M, Jia H B, Hu X L, . Characteristics of Landslides Induced by the Great Wenchuan Earthquake. Journal of Earth Science, 2010, 21(1): 104-113.

[23] Wang F W, Cheng Q G, Highland L, . Preliminary Investigation of Some Large Landslides Triggered by the 2008 Wenchuan Earthquake, Sichuan Province, China. Landslides, 2009, 6: 47-54.

[24] Wang Y F, Cheng Q G, Zhu Q. Inverse Grading Analysis of Deposit from Rock Avalanches Triggered by Wenchuan Earthquake. Chinese Journal of Rock Mechanics and Engineering, 2012, 31(6): 1089-1106.

[25] Wu Z H, Zhang Z C. Types of Seismic and Geological Hazards Caused by the M _s 8.0 Wenchuan Earthquake. Acta Geologica Sinica, 2008, 82(12): 1747-1756.

[26] Xu C. Distribution Law and Risk Assessment for Wenchuan Earthquake-Triggered Landslides. Chinese Journal of Rock Mechanics and Engineering, 2012, 31(2): 432-432.

[27] Xu C, Xu X W, Yao X, . Three (nearly) Complete Inventories of Landslides Triggered by the May 12, 2008 Wenchuan M _w 7.9 Earthquake of China and Their Spatial Distribution Statistical Analysis. Landslides, 2013

[28] Xu C, Xu X W, Yao Q, . GIS-Based Bivariate Statistical Modelling for Earthquake-Triggered Landslides Susceptibility Mapping Related to the 2008 Wenchuan Earthquake, China. Quarterly Journal of Engineering Geology and Hydrogeology, 2013, 46(2): 221-236.

[29] Xu C, Xu X W, Zhou B G, . Revisions of the M 8.0 Wenchuan Earthquake Seismic Intensity Map Based on Co-Seismic Landslide Abundance. Natural Hazards, 2013, 69(3): 1459-1476.

[30] Xu C, Xu X W, Zheng W J, . Landslides Triggered by the April 20, 2013 Lushan, Sichuan Province M _s 7.0 Strong Earthquake of China. Seismology and Geology, 2013, 35(3): 641-660.

[31] Xu X W, Wen X Z, Yu G H, . Co-Seismic Reverse- and Oblique-Slip Surface Faulting Generated by the 2008 M _w 7.9 Wenchuan Earthquake, China. Geology, 2009, 37(6): 515-518.

[32] Xu Z Q, Hou L W, Wang Z X. Orogenic Processes of Songpan-Ganzi Belt in China, 1992 Beijing: Geological Publishing House, 172-190.

[33] Xu X W, Chen G H, Yu G H, . Seismogenic Structure of Lushan Earthquake and Its Relationship with Wenchuan Earthquake. Earth Science Frontiers, 2013, 20(3): 11-20.

[34] Yin Y P, Wang F W, Sun P. Landslide Hazards Triggered by the 2008 Wenchuan Earthquake, Sichuan, China. Landslides, 2009, 6(2): 139-152.

[35] Yin Y P, Zheng W M, Li X C, . Catastrophic Landslides Associated with the M 8.0 Wenchuan Earthquake. Bulletin of Engineering Geology and the Environment, 2011, 70: 15-32.

[36] Yin Y P, Wang M, Li B, . Dynamic Response Characteristics of Daguangbao Landslide Triggered by Wenchuan Earthquake. Chinese Journal of Rock Mechanics and Engineering, 2012, 31(10): 1969-1982.

[37] Zhang Y S, Dong S W, Hou C T, . Geo-Hazards Induced by the Lushan M _s 7.0 Earthquake in Sichuan Province, Southwest China: Typical Examples, Types and Distributional Characteristics. Acta Geologica Sinica (English Edition), 2013, 87(3): 646-657.