Wenchuan Earthquake-stricken Area Research Articles

How do rural households adapt to multiple natural hazards in disaster-prone areas? A case study of the Wenchuan earthquake-stricken area, China

How do rural households adapt to multiple natural hazards in disaster-prone areas? A case study of the Wenchuan earthquake-stricken area, China

Does Disaster Severity Have a Long-Term Effect on Survivors' Disaster Preparedness? A Survey a Decade after the 2008 Wenchuan Earthquake in China.

Disaster experiences have long-term effects on disaster preparedness. This study examined the long-term (10-y) effect of disaster severity of the 2008 Wenchuan earthquake on survivors' disaster preparedness and the moderating effects of household vulnerability. The data were collected in January 2018 covering 30 counties in Wenchuan earthquake-stricken areas. The dependent variable was survivors' disaster preparedness (including overall, material, knowledge and awareness, and action preparedness) in 2018. Disaster severity included survivors' housing damage and county death rate caused by the earthquake in 2008. Household vulnerability is a set of conditions that negatively affects the ability of people to prepare for and withstand disaster, proxied by households' per-capita income and the highest years of schooling of household members. We performed multivariable linear regression models to answer the research questions. A higher county death rate was associated with better overall preparedness (β = 0.043; P < 0.05) and knowledge and awareness preparedness (β = 0.018; P < 0.05), but housing damage was not significantly associated with disaster preparedness. The positive association of county death rate with overall preparedness (β = -0.065; P < 0.05) becomes weaker when a household has a higher per-capita income. Also, with the household per-capita income increasing, the associations of county death rate with material preparedness (β = -0.037; P < 0.05) and action preparedness (β = -0.034; P < 0.01) become weaker. Disaster severity has positive and long-term effects on survivors' disaster preparedness. Also, the positive and long-term effects are affected by household vulnerability. Specifically, the positive and long-term effects of disaster severity on disaster preparedness are more substantial when a household is more vulnerable.

The Spatiotemporal Variations in Soil Erosion and Its Dominant Influencing Factors in the Wenchuan Earthquake-Stricken Area

Earthquakes have obvious influences on the spatiotemporal changes in soil erosion intensity in earthquake-stricken areas. However, fewer studies have been conducted to evaluate the spatiotemporal changes in soil erosion before and after the Wenchuan earthquake and its dominant factors in different periods. In order to explore the above issue, this study quantitatively analyzed the spatiotemporal variation characteristics of soil erosion in the Wenchuan earthquake-stricken area from 2000 to 2019 based on the RUSLE model, gravity center model, and its dominant factors in different periods were determined using Geodetector. The research results indicated that: (1) The amount of mean total erosion in the Wenchuan earthquake-stricken area during 2000–2019 was 10.05 × 108 t, with an average soil erosion modulus of 2038.2 t/(km2·a), indicating mild erosion. (2) The spatiotemporal patterns of soil erosion changed greatly in the Wenchuan earthquake-stricken areas during 2000–2019. Areas with intensified soil erosion were mainly distributed in Lixian, Wenchuan, Xiaojin, and other areas near the Longmenshan fault zones. (3) Landslides, debris flows, and floods caused by the Wenchuan earthquake contributed to aggravating the soil erosion intensity in the stricken area. (4) During 2000–2019, the soil erosion intensity showed an overall decreasing trend, while the soil erosion intensity showed an increasing trend around 2008 due to the Wenchuan earthquake. (5) During 2000–2019, soil erosion in the Wenchuan earthquake-stricken area has been greatly affected by vegetation, terrain, and land use types. The research results could provide important decision-making support for soil erosion prevention and ecosystem restoration in the Wenchuan earthquake-stricken area. In addition, these results would be conducive to revealing and understanding the interactive process of “Water–Soil–Vegetation” in mountainous regions all over the world.

Integrating the SLIDE model within CAESAR-Lisflood: Modeling the ‘rainfall-landslide-flash flood’ disaster chain mechanism under landscape evolution in a mountainous area

The interaction mechanism between the dynamically changing environment and the subsequent natural hazards in the years following an earthquake has been studied based on a multi-temporal remote sensing dataset and continually measured data. However, how to quantitatively model this interaction mechanism has not been fully addressed. In this study, we first modeled the interaction mechanism between the ‘rainfall-landslide-flash flood’ disaster chain and the dynamically changing environment in mountainous areas by incorporating the SLope-Infiltration-Distributed Equilibrium (SLIDE) model within the landscape evolution model (CAESAR-Lisflood) and then applied the integrated CAESAR-Lisflood model in a Wenchuan earthquake-stricken area. The results demonstrated that the landslide susceptibility under extreme rainfall can be predicted effectively based on the integrated CAESAR-Lisflood model and that new/enlarged landslides occur more easily in mountain valleys, near the valley outlet, and in the main steep gullies. Most of the high landslide susceptibility areas are not located in coseismic landslide areas with high vegetation recovery. The landslide legacy effects had a significant influence on the landscape erosion and deposition processes and a great effect on the spatial distribution pattern of the material redistribution in the basin, which in turn affected the subsequent disaster occurrence. The integrated CAESAR-Lisflood model compensates for the effect of the “rainfall-landslide-flash flood” disaster chain on the process of erosion and deposition, improves the model’s applicability in earthquake-stricken areas, and provides scientific information for regional disaster management and reduction.

Determinants of villagers’ satisfaction with post-disaster reconstruction: Evidence from surveys ten years after the Wenchuan earthquake

Residents’ satisfaction with post-disaster reconstruction in earthquake-stricken areas directly affects their quality of life, which cannot be ignored in post-disaster reconstruction. More than 10 years after the Wenchuan earthquake, we took ten randomly selected villages in the five areas hardest-hit by the Wenchuan earthquake as research objects and obtained 483 valid completed questionnaires. The villagers were randomly sampled and descriptive statistical analysis, factor analysis, and ordered logistic regression were used to explore the factors and relationships influencing villagers’ satisfaction with post-disaster reconstruction in Wenchuan earthquake-stricken areas. The results show that: 1) the more rural residents know about the post-disaster reconstruction, the greater their level of satisfaction; 2) the more the annual income of families increases after resettlement, the greater the satisfaction of rural residents with the post-disaster reconstruction; 3) six public factors, namely the village committee acts as, housing construction quality, public service, policy of benefiting farmers, cultural environment, and hardware environment, all significantly positively affect residents’ overall satisfaction with post-earthquake reconstruction. This study thus enriches the theory of residents’ satisfaction studies and the practice of post-earthquake reconstruction.

The Large-Scale Investigation and Analysis of Lophodermium piceae in Subalpine Areas Based on Satellite Multi-Spectral Remote Sensing

Picea asperata, a common tree species in the subalpine areas of Li County, Sichuan Province, China, is susceptible to Lophodermium piceae. Remote sensing has the advantages of large-scale, fast information acquisition, and low cost, which can overcome the shortcomings of ground survey. Hence, we used Landsat 8 satellite multi-spectral images and forest resource distribution data to investigate and analyze this forest disease at a large scale. Firstly, we extracted the spatial distribution information of Picea asperata and chose a temporal sequence indicator to establish a regression model and obtained a significantly negative correlation between the damage degree of plants and the change rate of normalized difference vegetation index (NDVI). Accordingly, the investigation results of the disease have good consistency with the ground survey data in spatial distribution and damage degree. On this basis, a temporal regression analysis was performed by combining the remote sensing investigation results with climate variables, and canonical correspondence analysis (CCA) was utilized in the spatial comprehensive analysis of Lophodermium piceae with terrain, soil and forest stand factors. Conclusively, this study effectively coped with the difficulties in full investigation and analysis of Lophodermium piceae in ecologically fragile subalpine areas of Western Sichuan. It is of important reference value in the early warning and monitoring of this disease, and also provides objective and reliable information support for ecological restoration and management planning in the Wenchuan earthquake-stricken areas.

To stay or to move? Investigation on residents' migration intention under frequent secondary disasters in Wenchuan earthquake-stricken area.

The deterioration of the living environment caused by the earthquake is the main migration motivation of residents in the area of the secondary earthquake disaster, and their migration intention is one of the most important factors affecting residents' happiness. This paper uses 957 effective survey samples from 12 secondary geological disaster areas after the Wenchuan earthquake to research the migration intention of residents and its influencing factors. It can be found that 45.2% of residents are willing to migrate, which means they have an instinctive reaction to profit-seeking and harm-avoiding, but it has not become a realistic choice. Investigation facts and research results show that the instinctive response of profit-seeking and harm-avoiding drives residents to make different choices. The migration of residents in areas where secondary geological disasters occur is affected not only by disasters such as debris flow, landslides, and collapse, but also by many factors such as life convenience, family income, expectations for future life, gender, education level, psychological feeling. The improved life and the optimization of the economic conditions brought about by the success of post-disaster reconstruction have made the vast majority of people more confident in the future of the disaster-stricken areas, which made most people choose to stay in those areas. This paper will provide policy suggestions for residents' migration and the reconstruction of the local social governance system in secondary geological disaster areas, which is helpful to improve ecological livability and residents' happiness in the Wenchuan earthquake-stricken area.

Landscape evolution of the Wenchuan earthquake-stricken area in response to future climate change

The Wenchuan earthquake caused rapid and gradual changes to the local geomorphology in the earthquake-stricken area. Extreme rainfall events can have strong impacts on local geomorphic evolution and alter the risks of subsequent geohazards and flooding. However, there is still lack of understanding of long-term geomorphic and fluvial evolution in face of changing future climate. In this paper, we first perform the future extreme rainfall projection and then analyze the landscape evolution variation under future climate change with the CAESAR-Lisflood model. A new approach to applying the ‘NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP)’ dataset at the local scale is presented, and a future landscape evolution analysis is conducted. We used spatial (tailoring process) and statistical temporal downscaling methods with NEX-GDDP data to project future extreme rainfall in combination with the CAESAR-Lisflood model to simulate the landscape evolution in response to climate change. The results showed that the future rainfall projection model can provide the most robust and effective representative of future climate change scenarios at the local scale, the geological and geomorphological environment of the basin continues to change dynamically after the earthquake, and nearly 27 years (~2035) are needed before the geomorphology of the basin stabilizes, and then, the yearly yield remains at an average rate of 1 × 104 m3. Post-earthquake mountainous area response and recovery characteristics to a changing future climate can provide important information on future geohazard projections and measures to be taken.

Exploration on the risk factors of pulmonary tuberculosis incidence in Wenchuan earthquake-stricken area

To explore the risk factors of pulmonary tuberculosis incidence in Wenchuan earthquake-stricken area during a nine-year period of time. The incidence and socioeconomic indicators in the 181 counties of Sichuan province from 2004 to 2012 were collected, multilevel extra-Poisson model was performed for variable screening, and Bayesian spatiotemporal models were fitted. The morbidity showed a downward time trend from 2004 to 2012. The spatiotemporal interaction model was applied with the smallest deviance information criterion. The risk factors included: county latitude (0.949, 95%CI 0.765 to 1.098), float proportion (0.368, 95%CI 0.354 to 0.380), per capita GDP (-0.225, 95%CI -0.235 to -0.216), population density (0.072, 95%CI 0.041 to 0.105), and minority inhabited area (0.302, 95%CI 0.241 to 0.372). The variation of posterior median and Bayesian credibility interval was small, and the spatiotemporal patterns were similar among different periods. The incidence presented a smooth curve without bursting after the earthquake during 2004 to 2012, and with a tendency of decreasing from north to south in Sichuan province; PTB countermeasures should be focused on the migrating population and in the minority inhabited and economic underdeveloped regions. Geographical adjacent structure was an important factor and regional collaborative prevention and control should be strengthened.

Hazard assessment of debris flows in the Wenchuan earthquake-stricken area, South West China

The Longxi river basin with the city of Dujiangyan, in the Sichuan province of South West China, belongs to the seismic area of the May 12, 2008 Wenchuan earthquake. Lots of loose co-seismic materials were present on the slopes, which in later years served as source material for rainfall-induced debris flows. A total of 12 debris flows, were triggered by heavy rainfall on August 13, 2010 in the study area. The FLO-2D numerical analysis software was adopted to simulate debris flows intensity, including movement velocities and maximum flow depths. A comparison of the measured fan spreading with the simulation results, the evaluation parameter Ω was used to verify accuracy of simulation, the results show Ω values ranging between 1.37 and 1.65 indicating relative good simulation results. This study also estimated the flood hydrograph for various recurrence intervals (20, 100, and 200 years, respectively) to perform scenario simulations of debris flows, and followed Swiss and Austrian standards to establish a debris flow hazard classification model on the basis of a combination of the debris flow intensity and the recurrence period. This study distinguishes three hazard classes: low, medium, and high. This proposed approach generated a debris flow hazard distribution map that could be used for disaster prevention in the Wenchuan earthquake-stricken area, South West China.

Spatial epidemiology and risk factors of pulmonary tuberculosis morbidity in Wenchuan earthquake-stricken area.

China is a country that experiences frequent earthquakes and has a high pulmonary tuberculosis burden. In this study, we aimed to explore the spatial clustering and risk factors of the reported incidence of pulmonary tuberculosis burden before and after the Wenchuan earthquake. Data on the location and the demographic, socioeconomic, and health service characteristics of the 181 counties of Sichuan province from 2004 to 2012 were collected. Global and local spatial autocorrelation analyses were performed to explore spatial clustering. The associated factors were screened using stepwise multiple linear regression, and a spatial lag model was fitted to explore the influence factors. The incidence of pulmonary tuberculosis burden showed a global and local spatial autocorrelation relationship. The high-incidence counties shifted gradually over time from east to west and finally clustered in the "Aba-Ganzi" region. Factors influencing the incidence of pulmonary tuberculosis burden included minority areas, the proportion of the working population, county latitude, and the severity of the earthquake. The influence factors varied over time; the impact of minority regions, occupation, and health resources allocation weakened, whereas the economic development and mobility of the population became more significant. The spatial structural relationship is an important factor related to pulmonary tuberculosis burden incidence. More attention should be paid to high-incidence areas and populations susceptible to pulmonary tuberculosis burden.

Reliability and validity of Professional Quality of Life Scale among government staff in earthquake - stricken areas in China

To evaluate the reliability and validity of Professional Quality of Life Scale (ProQOL-30, 4th version, 30 items) among government staff in the Wenchuan earthquake-stricken areas A total of 1,175 members of government staff in the Wenchuan earthquake-stricken areas were selected by convenience sampling and required to complete the ProQOL and Self-Reporting Questionnair (SRQ). The reliability and validity of the scale was evaluated by correlation analysis, t-test, and confirmatory factor analysis. Item-total correlation coefficients of the three subscales were 0.590 - 0.752, 0.389 - 0.603, and 0.340 - 0.647, respectively (P<0.05), and the average coefficients were 0.672, 0.482, and 0.555 respectively (P<0.05). The Cronbach's α coefficients of the three subscales were 0.864, 0.569, and 0.742 respectively, and the split-half reliabilities were 0.829, 0.490, and 0.677, respectively. P value was 0.88 in thE chi-square test of confirmatory factor analysis model. Goodness-of-fit indices of ProQOL-30 included GFI=0.895 NFI=0.856, CFI=0.895, RMSEA=0.063, and AGFI=0.912. For the ProQOL-28 as an optimized version o ProQOL-30, the Cronbach's a coefficients for burnout and trauma/compassion fatigue increased to 0.616 and 0.757, respectively. P value was 0.91 in the chi-square test of confirmatory factor analysis model test. Goodness-of-fit indices of ProQOL-28 were GFI =0.913, AGFI =0.924, NFI =0.900, CFI =0.913, and RMSEA =0.031 CONCLUSION: ProQOL-28 has good reliability and validity among government staff in the earthquake-stricker areas in China.

Rainfall thresholds for debris flow initiation in the Wenchuan earthquake-stricken area, southwestern China

The Wenchuan earthquake-stricken area is frequently hit by heavy rainfall, which often triggers sediment-related disasters, such as shallow landslides, debris flows, and related natural events, sometimes causing tremendous damage to lives, property, infrastructure, and environment. The assessment of the rainfall thresholds for debris flow occurrence is very important in order to improve forecasting and for risk management. In the context of the Wenchuan earthquake-stricken area, however, the rainfall thresholds for triggering debris flows are not well understood. With the aim of defining the critical rainfall thresholds for this area, a detailed analysis of the main rainstorm events was carried out. This paper presents 11 rainfall events that induced debris flows which occurred between 2008 and 2012 after the Wenchuan earthquake. The rainfall thresholds were defined in terms of mean rainfall intensity I, rainfall duration D, and normalized using the mean annual precipitation (MAP). An ID threshold and a normalized I MAP D threshold graph could be set up for the Wenchuan earthquake-stricken area which forms the lower boundary of the domain with debris flow-triggering rainfall events. The rainfall threshold curves obtained for the study area were compared with the local, regional, and global curves proposed by various authors. The results suggest that debris flow initiation in the study area almost requires a higher amount of rainfall and greater intensity than elsewhere. The comparison of rainfall intensity prior to and after the earthquake clearly indicates that the critical rainfall intensity necessary to trigger debris flows decreased after the earthquake. Rainfall thresholds presented in this paper are generalized, so that they can be used in debris flow warning systems in areas with the same geology as the Wenchuan earthquake-stricken area.

Earthquake Insurance and Earthquake Risk Management

ABSTRACT The Wenchuan earthquake is the largest devastating earthquake striking China since the 1976 Tangshan earthquake. In this catastrophe, loss payments were mainly from the government and public endowment. The insurance industry is expected to take more responsibility in the future, since earthquake insurance is one of the most effective and equitable instruments to disperse earthquake losses. In this article, earthquake risk management and the development of earthquake insurance in China are reviewed. Earthquake insurance is suggested as an instrument in earthquake risk management, where the premium rate of earthquake insurance is a key factor that needs to be determined reasonably. Seismic hazard is analyzed for the Wenchuan earthquake-stricken area, and is combined with primary loss estimation to construct the exceeding probability curve. Earthquake insurance premium rates are calculated for buildings in the area, including RC (Reinforced Concrete), frame, and brick, corresponding to two kinds of insurance deductible.

Erratum to: The Critical Rainfall Characteristics for Torrents and Debris Flows in the Wenchuan Earthquake Stricken Area

Erratum to: The Critical Rainfall Characteristics for Torrents and Debris Flows in the Wenchuan Earthquake Stricken Area

Relationship between post-traumatic stress disorder and perceived social support among middle school students in Wenchuan earthquake-stricken

To explore the relationship between post-traumatic stress disorder (PTSD) and perceived social support (PSS) ability among middle school students in earthquake-stricken areas after the Wenchuan earthquake accident. A total of 1966 students from three secondary schools of Wenchuan earthquake-stricken areas were evaluated by PTSD Checklist-Civilian Version (PCL-C) and Perceived Social Support Scale (PSSS). The overall incidence rate of PTSD was 78.3%, with severe PTSD as 24.38%. Significant differences on the incidence rates of PTSD were found among the students who were in different PSS levels (P < 0.05) and significant negative correlation existed between the levels of severity on PTSD and PSS (gamma = -0.226, P < 0.05). Significant differences on PTSD incidence rates were found among those students who were from different families or out-family PSS levels (P = 0.009, P < 0.05). Significant negative correlation existed between the severity of PTSD and family or out-family PSS level (gamma = -0.176, P < 0.05, gamma = -0.214, P < 0.05). Relationships between the incidence rate, severity of PTSD and PSS levels existed among the middle school students in Wenchuan earthquake-stricken areas, with higher PSS, lower incidence rate and lighter severity of PTSD. Psychological intervention for earthquake-stricken students should be carried out.