摘要 :
Landslides cause huge human and economic losses globally.Detecting landslide precursors is crucial for disaster prevention.The small baseline subset interferometric synthetic-aperture radar(SBAS-InSAR)has been a popular method for...
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Landslides cause huge human and economic losses globally.Detecting landslide precursors is crucial for disaster prevention.The small baseline subset interferometric synthetic-aperture radar(SBAS-InSAR)has been a popular method for detecting landslide precursors.However,non-monotonic displacements in SBAS-InSAR results are pervasive,making it challenging to single out true landslide signals.By exploiting time series displacements derived by SBAS-InSAR,we proposed a method to identify moving landslides.The method calculates two indices(global/local change index)to rank monotonicity of the time series from the derived displacements.Using two thresholds of the proposed indices,more than 96%of background noises in displacement results can be removed.We also found that landslides on the east and west slopes are easier to detect than other slope aspects for the Sentinel-1 images.By repressing background noises,this method can serve as a convenient tool to detect landslide precursors in mountainous areas.
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摘要 :
Urbanization can be a challenge and an opportunity for earthquake risk mitigation.However,little is known about the changes in exposure(for example,population and urban land)to earthquakes in the context of global urbanization,and...
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Urbanization can be a challenge and an opportunity for earthquake risk mitigation.However,little is known about the changes in exposure(for example,population and urban land)to earthquakes in the context of global urbanization,and their impacts on fatalities in earthquake-prone areas.We present a global analysis of the changes in population size and urban land area in earthquake-prone areas from 1990 to 2015,and their impacts on earthquake-related fatalities.We found that more than two thirds of population growth(or 70%of total population in 2015)and nearly three quarters of earthquake-related deaths(or 307,918 deaths)in global earthquake-prone areas occurred in developing countries with an urbanization ratio(percentage of urban population to total population)between 20 and 60%.Holding other factors constant,population size was significantly and positively associated with earthquake fatalities,while the area of urban land was negatively related.The results suggest that fatalities increase for areas where the urbanization ratio is low,but after a ratio between 40 and 50%occurs,earthquake fatalities decline.This finding suggests that the resistance of building and infrastructure is greater in countries with higher urbanization ratios and highlights the need for further investigation.Our quantitative analysis is extended into the future using Shared Socioeconomic Pathways to reveal that by 2050,more than 50%of the population increase in global earthquake-prone areas will take place in a few developing countries(Pakistan,India,Afghanistan,and Bangladesh)that are particularly vulnerable to earthquakes.To reduce earthquake-induced fatalities,enhanced resilience of buildings and urban infrastructure generally in these few countries should be a priority.
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