scholarly journals Monitoring of the reconstruction process in a high mountainous area affected by a major earthquake and subsequent hazards

2020 ◽  
Vol 20 (4) ◽  
pp. 1163-1186 ◽  
Author(s):  
Chenxiao Tang ◽  
Xinlei Liu ◽  
Yinghua Cai ◽  
Cees Van Westen ◽  
Yu Yang ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Economic Value ◽  
Image Interpretation ◽  
Economic Loss ◽  
Field Investigation ◽  
Mitigation Measures ◽  
Mountainous Area ◽  
Reconstruction Process ◽  
2008 Wenchuan Earthquake ◽  
Recovery Planning

Abstract. Recovering from major earthquakes is a challenge, especially in mountainous environments where postearthquake hazards may cause substantial impacts for prolonged periods of time. Although such impacts were reported in the 1923 Great Kantō earthquake and the 1999 Chi-Chi earthquake, careless reconstruction in hazard-prone areas and consequently huge losses were witnessed following the 2008 Wenchuan earthquake in the Sichuan province of China, as several reconstructed settlements were severely damaged by mass movements and floods. In order to summarize experiences and identify problems in the reconstruction planning, a monitoring of one of the settlements, the town of Longchi, was carried out by image interpretation and field investigation. Seven inventories containing buildings, farmlands, roads and mitigation measures were made to study the dynamics of elements at risk and exposure over a period of 11 years. It was found that the total economic value of the newly reconstructed buildings was several times more than in the preearthquake situation in 2007, because of enormous governmental investment. Postseismic hazards were not sufficiently taken into consideration in the recovery planning before the catastrophic debris flow disaster in 2010. As a result, the direct economic loss from postseismic disasters was slightly more than the loss caused by the Wenchuan earthquake itself. The society showed an impact-adapt pattern, experiencing losses from disasters and then gaining resistance by abandoning buildings in hazard-prone areas and installing mitigation measures. The locations potentially exposed to postearthquake hazards were summarized, and a possible timetable for reconstruction was proposed. Problems might be encountered in hazard assessment, and possible solutions were discussed.

scholarly journals Monitoring of the reconstruction process in a high mountainous area affected by a large earthquake and subsequent debris flows

2019 ◽  
Author(s):  
Chenxiao Tang ◽  
Xinlei Liu ◽  
Yinghua Cai ◽  
Cees Van Westen ◽  
Yu Yang ◽  
...  
Keyword(s):  
Economic Value ◽  
Image Interpretation ◽  
Large Earthquake ◽  
Economic Loss ◽  
Mitigation Measures ◽  
Mountainous Area ◽  
Reconstruction Process ◽  
2008 Wenchuan Earthquake ◽  
Recovery Planning ◽  
Total Economic Value

Abstract. Recovering from major earthquakes is a challenge, especially in mountainous environments where post-earthquake mass movements and floods may cause substantial impacts. We monitored the reconstruction of Longchi town in Sichuan, China, over a period of 11 years, following the 2008 Wenchuan earthquake. Seven inventories of buildings, land use, roads and mitigation measures were made by using remote sensing image interpretation and field surveys. Most of the buildings were rebuild by 2010 and reconstruction was completed by 2012. The total economic value of the new buildings in 2010 was much more than the pre-earthquake situation in 2007. Unfortunately, post-seismic hazards were not sufficiently taken into consideration in the recovery planning before the catastrophic debris flow disaster in 2010. As a result, the direct economic loss from post-seismic disasters was more than the loss caused by the earthquake itself. The society showed an impact – adapt pattern, taking losses from disasters and then gaining resistance.

scholarly journals Particle flow and segregation in a giant landslide event triggered by the 2008 Wenchuan earthquake, Sichuan, China

2011 ◽  
Vol 11 (4) ◽  
pp. 1153-1162 ◽  
Author(s):  
L. M. Zhang ◽  
Y. Xu ◽  
R. Q. Huang ◽  
D. S. Chang
Keyword(s):  
Wenchuan Earthquake ◽  
Particle Diameter ◽  
Field Investigation ◽  
Particle Flow ◽  
Long Distance ◽  
2008 Wenchuan Earthquake ◽  
Landslide Event ◽  
Large Particles ◽  
Landslide Process ◽  
Initial Deposition

Abstract. During the 12 May 2008 Wenchuan earthquake, a large landslide of approximately 30 million m3 occurred at Donghekou with a particle run-out distance of over 2000 m. This paper presents fascinating particle flow and segregation characteristics in the landslide process found through field investigation of changes in the soil particle size, density, and fabric along the particle movement paths. The soil particles experienced projection, long-distance flying, sliding, and rolling. Trajectory segregation, inverse grading, and particle crushing were found in the landslide event, which contributed to the heterogeneity of the soil deposits. In the initial deposition area, particles with larger diameters appeared to have flown longer. Materials from different sources mixed, forming more uniform debris. In the run-out area, the particle flow tended to cause large particles to travel further. However, particle disintegration and crushing led to more small particles along the movement paths and the observed characteristic flow distances of very large particles did not increase with the particle diameter, which is different from observations of an idealized granular mass flow.

THE MECHANISM OF INITIATION AND MOTION OF THE RAPID AND LONG RUNOUT LANDSLIDES TRIGGERED BY THE 2008 WENCHUAN EARTHQUAKE

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Wang F.W ◽  
Sun P. ◽  
Cheng Q.G. ◽  
Fukuoka H.
Keyword(s):  
Wenchuan Earthquake ◽  
Disaster Mitigation ◽  
Great Earthquake ◽  
Shear Tests ◽  
Long Runout ◽  
Reconstruction Process ◽  
2008 Wenchuan Earthquake ◽  
The 2008 Wenchuan Earthquake ◽  
Ring Shear ◽  
Ring Shear Tests

The 2008 Wenchuan earthquake triggered many rapid and long runout landslides, which made great loss of property and human lives directly. It is very important to understand the mechanism of initiation and motion of the rapid and long runout landslides. In this paper, field investigations on some typical landslides are introduced at first, and then the ring shear tests for simulating the initiation and motion of the Donghekou landslide are presented in details. The real seismic wave monitored in Shifang station was applied in the simulation test for the landslide initiation, while three different conditions of water content (dry, partially saturated, and fully saturated) were applied for the samples in the simulation tests to simulate landslide motion. It was found that the valley water and groundwater played a key role in the long runout and rapid landslide motion process during the great earthquake. This makes the difference for where landslide occurred but stopped soon and where landslides moved for long distance with high speed and killed many people. For the purpose of disaster mitigation, we strongly suggest that:(a) Avoid locating village in the landslide motion path, because the same event will occur in the future; (b) Avoid locating village and people on the landslide, because the landslide will deform easily with the seismic activity; (c) The attention should also be paid for landslide and debris flow during the reconstruction process for disaster mitigation in long period. Keywords: Wenchuan Earthquake, rapid and long runout landslides, ring shear tests, initiation, motion

scholarly journals Analysing post-earthquake landslide activity using multi-temporal landslide inventories near the epicentral area of the 2008 Wenchuan earthquake

2016 ◽  
Vol 16 (12) ◽  
pp. 2641-2655 ◽  
Author(s):  
Chenxiao Tang ◽  
Cees J. Van Westen ◽  
Hakan Tanyas ◽  
Victor G. Jetten
Keyword(s):  
Wenchuan Earthquake ◽  
Image Interpretation ◽  
Extreme Rainfall ◽  
Visual Image ◽  
Extreme Rainfall Events ◽  
Epicentral Area ◽  
2008 Wenchuan Earthquake ◽  
Landslide Activity ◽  
Mountainous Regions ◽  
The 2008 Wenchuan Earthquake

Abstract. Large earthquakes in mountainous regions may trigger thousands of landslides, some active for years. We analysed the changes in landslide activity near the epicentre of the 2008 Wenchuan earthquake by generating five landslide inventories for different years through stereoscopic digital visual image interpretation. From May 2008 to April 2015, 660 new landslides occurred outside the co-seismic landslide areas. In April 2015, the number of active landslides had gone down to 66, less than 1 % of the co-seismic landslides, but still much higher than the pre-earthquake levels. We expect that the landslide activity will continue to decay, but may be halted if extreme rainfall events occur.

Landslide hazard assessment of the 2008 Wenchuan earthquake: a case study in Beichuan area

2011 ◽  
Vol 48 (1) ◽  
pp. 128-145 ◽  
Author(s):  
Chuan Tang ◽  
Jing Zhu ◽  
Xin Qi
Keyword(s):  
Wenchuan Earthquake ◽  
Large Scale ◽  
Landslide Hazard ◽  
Landslide Risk ◽  
Reconstruction Process ◽  
2008 Wenchuan Earthquake ◽  
Landslide Occurrence ◽  
The Wenchuan Earthquake ◽  
Very High ◽  
Earthquake Area

The Wenchuan earthquake (magnitude Ms = 8.0) of 12 May 2008 triggered widespread and large-scale landslides over an area of about 50 000 km2. A study was undertaken to determine the primary factors associated with seismic landslide occurrence. An index-based approach used to assess earthquake-triggered landslide hazard in the central part of the Wenchuan earthquake area affected is described. Slope gradient, relief amplitude, lithology, bedding–slope relations, fault proximity, stream proximity, and antecedent rainfall are recognized as factors that may have had an important influence on landslide occurrence. The assessment of the influence of each of these factors is presented through use of a series of maps showing areas of low, moderate, high, and very high landslide hazard. Areas identified as having “very high and high landslide hazard” were located along the earthquake-source fault and along both banks of the Jian River. The role of rainfall is very significant for future landslide occurrence in the earthquake area. The results of this study will assist decision makers in the selection of safe sites during the reconstruction process. The maps can also be used for landslide risk management in the study area.

scholarly journals Analysing post-earthquake landslide activity using multi-temporal landslide inventories near the epicentral area of the 2008 Wenchuan earthquake

2016 ◽  
Author(s):  
Chenxiao Tang ◽  
Cees J. Van Westen ◽  
Hakan Tanyaş ◽  
Victor G. Jetten
Keyword(s):  
Wenchuan Earthquake ◽  
Image Interpretation ◽  
Extreme Rainfall ◽  
Visual Image ◽  
Extreme Rainfall Events ◽  
Epicentral Area ◽  
2008 Wenchuan Earthquake ◽  
Landslide Activity ◽  
Mountainous Regions ◽  
Seismic Landslide

Abstract. Large earthquakes in mountainous regions may trigger thousands of landslides, some active for years. We analysed the changes in landslide activity near 2008 Wenchuan earthquake epicentre, generating five landslide inventories for different years through stereoscopic digital visual image interpretation. From May 2008 to April 2015, 660 new landslides occurred outside the co-seismic landslide areas. In April 2015, the number of active landslides had gone down to 66, less than 1 % of the co-seismic landslides, still much higher than the pre-earthquake situation. We expect that the landslide activity will continue to decay, but may be halted if extreme rainfall events occur.

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