scholarly journals Evaluation of MODIS-based Vegetation Restoration After the 2008 Wenchuan Earthquake

2021 ◽  
Vol 308 ◽  
pp. 02005
Author(s):  
Cheng Jin ◽  
Kai Yu ◽  
Ke Zhang

Mountainous vegetation recovery after major earthquakes has been significant for preventing post-seismic soil erosion and geo-hazards. Magnitude 7.9 Wenchuan earthquake struck western Sichuan, China in 2008, caused salient number of geological hazards and caused major vegetation damage. This recovery process could be a very long and fluctuating. And Remote sensing has been an important method of vegetation restoration monitoring. This study aims to use remote sensing technology data to analyze the post-seismic vegetation damage and recovery situation of the 2008 Wenchuan earthquake over years to 2020, and find the relevant factors affecting the restoration of ecological vegetation. This paper examined the vegetation recovery processes following the 2008 Wenchuan earthquake using 16-day interval MODIS normalized difference vegetation index time series from 2000 to 2020. It has been found that the vegetation recovery rate generally increased by years, the entire study area has recovered 49.89% by 2020. In addition, by combining remote sensing imagery and geographic information data, we also found that the heavily affected vegetation areas are mainly located along the southern part of the earthquake surface rupture, where have a very high slope which mainly over 60 degrees. It makes this part having higher probabilities to experiences secondary natural hazards and a fluctuating vegetation recovery rate. Through this research, it can be concluded that remote sensing is an effective method for monitoring vegetation dynamics in a long series. For soil and soil retention and ecological vegetation protection of landslides after the earthquake, it should be more concerned about the areas where have steep slope that over 60 degrees.

Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1305
Author(s):  
Feliu Serra-Burriel ◽  
Pedro Delicado ◽  
Fernando M. Cucchietti

In recent years, wildfires have caused havoc across the world, which are especially aggravated in certain regions due to climate change. Remote sensing has become a powerful tool for monitoring fires, as well as for measuring their effects on vegetation over the following years. We aim to explain the dynamics of wildfires’ effects on a vegetation index (previously estimated by causal inference through synthetic controls) from pre-wildfire available information (mainly proceeding from satellites). For this purpose, we use regression models from Functional Data Analysis, where wildfire effects are considered functional responses, depending on elapsed time after each wildfire, while pre-wildfire information acts as scalar covariates. Our main findings show that vegetation recovery after wildfires is a slow process, affected by many pre-wildfire conditions, among which the richness and diversity of vegetation is one of the best predictors for the recovery.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yunge Fan ◽  
Lili Guan ◽  
Hu Xiang ◽  
Xianmei Yang ◽  
Guoping Huang ◽  
...  

Abstract Background The current study examined the change in local government staff’s emotional distress over 7 years after the 2008 Wenchuan earthquake, and the influence of earthquake exposure and professional quality of life (ProQOL) on emotional distress. Methods This longitudinal study assessed 250 participants at 1 year after the earthquake; 162 (64.8%) were followed up at 7 years. Emotional distress was assessed with the Self-Reporting Questionnaire (SRQ) at both time points. We assessed ProQOL, including compassion satisfaction, burnout, and secondary traumatic stress, and earthquake exposure at 1 year. Wilcoxon signed-rank tests were performed to test longitudinal changes in emotional distress. Hierarchical multiple regression was conducted to examine the effect of earthquake exposure and ProQOL. Results The positive screening rate of emotional distress (SRQ ≥ 8) was 37.6 and 15.4% at one and 7 years, respectively. Emotional distress scores declined over time (p < 0.001). Earthquake exposure and ProQOL predicted one-year (ps < 0.05) but not seven-year emotional distress, whereas burnout predicted both one-year (p = 0.018) and seven-year (p = 0.047) emotional distress. Conclusions Although emotional distress can recover over time, it persists even 7 years later. Actions to reduce burnout during the early stage of post-disaster rescue have long-term benefits to staff’s psychological outcomes.


2014 ◽  
Vol 57 (8) ◽  
pp. 1961-1971 ◽  
Author(s):  
RenMao Yuan ◽  
BingLiang Zhang ◽  
XiWei Xu ◽  
ChuanYong Lin ◽  
LanBing Si ◽  
...  

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