Large earthquakes initiate chains of surface processes that last much longer than the brief moments of strong shaking. Most moderate‐ and large‐magnitude earthquakes trigger landslides, ranging from ...small failures in the soil cover to massive, devastating rock avalanches. Some landslides dam rivers and impound lakes, which can collapse days to centuries later, and flood mountain valleys for hundreds of kilometers downstream. Landslide deposits on slopes can remobilize during heavy rainfall and evolve into debris flows. Cracks and fractures can form and widen on mountain crests and flanks, promoting increased frequency of landslides that lasts for decades. More gradual impacts involve the flushing of excess debris downstream by rivers, which can generate bank erosion and floodplain accretion as well as channel avulsions that affect flooding frequency, settlements, ecosystems, and infrastructure. Ultimately, earthquake sequences and their geomorphic consequences alter mountain landscapes over both human and geologic time scales. Two recent events have attracted intense research into earthquake‐induced landslides and their consequences: the magnitude M 7.6 Chi‐Chi, Taiwan earthquake of 1999, and the M 7.9 Wenchuan, China earthquake of 2008. Using data and insights from these and several other earthquakes, we analyze how such events initiate processes that change mountain landscapes, highlight research gaps, and suggest pathways toward a more complete understanding of the seismic effects on the Earth's surface.
Plain Language Summary
Strong earthquakes in mountainous regions trigger chains of events that modify mountain landscapes over days, years, and millennia. Earthquake shaking can cause many tens of thousands of landslides on steep mountain slopes. Some of these sudden slope failures can block rivers and form temporary lakes that can later collapse and cause huge floods. Other landslides move more slowly, in some cases in a stop‐start fashion during heavy rains or earthquake aftershocks. Debris from these landslides can clog channels, and during heavy rainfall, the debris can be transported downstream for many kilometers with catastrophic consequences. New landslides tend to happen more frequently than usual for months to years following an earthquake because the strong ground shaking has fractured and weakened the slopes. Other effects of large earthquakes can last, in various forms, over geologic time scales. Over the past two decades, our understanding of these issues has advanced because of the detailed study of the 1999 Chi‐Chi earthquake in Taiwan and the 2008 Wenchuan earthquake in China. We compile and discuss the results of research on these and other earthquakes and explain what we have learned, what we still need to know, and where we should direct future studies.
Key Points
Coupled surface processes initiated by strong seismic shaking are important hazards in mountain landscapes
Earthquake‐induced landslides pose challenges to hazard and risk assessment, management, and mitigation
Multidisciplinary approaches further the understanding of the earthquake hazard cascade, yet challenges remain
The catastrophic Tangjiawan landslide, triggered by the 2008 Wenchuan earthquake, blocked the Duba River, impounding one of the most dangerous coseismic barrier lakes in Beichuan, China. The lake was ...drained by an artificial spillway within one month after the earthquake to minimize the potential dam-breach flooding risk. However, on September 5, 2016, this landslide was reactivated and dammed the river again, creating a 20-m high dam at the same location and resulting in the formation of a barrier lake with a volume of 0.6 million m3. The day after the event we carried out a field investigation of the landslide and obtained a high-resolution image and DEM using UAV. The satellite images from 2005, 2008, 2010 and 2015 were also collected to analyze the evolution of the landslide. Together with multi-temporal DEMs, the geometry and volumes of the displaced mass and the landslide dams and barrier lakes were calculated using image interpretation and 3D spatial analysis with GIS. This landslide is of great scientific interest, as it presents a good example of multiple reactivation of a pre-historical giant landslide under different triggering conditions: a reactivation of an older landslide during the Wenchuan earthquake, and a second reactivation during a rainfall event several years later. Meanwhile from the hazard assessment and prevention perspective, it is also representative as it dammed the river twice in 2008 and 2016, posing threats to both upstream and downstream areas. We infer that the successive landslides in this region could be caused by the strong tectonic activities: including earthquakes and high average uplifting rate. The results of landslide volume analysis using multi-temporal DEMs, contribute to the landslide mechanism analysis, and suggest that the landslide volume estimation is effected by the landslide type, landslide rupture surface location, and resolution of DEM. We also compare the performance of different empirical models of landslide stability and dam-breach flood parameters and discuss their application during the quick assessment of the potential hazard of the landslide dams. Generally, the successive landslide dams at the Tangjiawan site are caused by the successive landslide reactivations on an anti-dip slope controlled by strong tectonic activity and river erosion, involve with a mass of loose materials of previous landslide deposition, and possess high flood risk to the downstream area. The experience gained in this work can be used to assist the hazard assessment and the planning of the emergency measures for similar landslide dams in the future.
•An UAV was applied to obtain high-resolution imagery and digital surface model of 2016 reactivation landslide.•Frequent earthquakes and high average uplifting rate were inferred to contributed to the successive damming events.•Multi-temporal remote sensing images were used to analyze the landslide evolution history.•The advantages and limitations of calculating landslide volume using multi-temporal DEMs were discussed.•The emergency mitigation experience was summarized to assist the future hazard assessment.
For decades society venerated advanced information and communications technologies (ICTs) as a source of economic rejuvenation and uplift. The financial crisis of 2007-08 shook such ideas. ...Originating in the United States, the driver of digital systems and services, the prolonged economic slump precipitated a perplexing historical outcome: a technological revolution wrapped inside an economic collapse. Dan Schiller analyzes the crisis tendencies of capitalism to root out the sources of this digital depression. From there he traces the economic re-composition wrought by ICTs, seeing them as a leading economic growth pole akin to the 1930s consumer industries that came out of the Great Depression. Finally, he lays out the present-day battles to capture and control digital technology and its growth. Demonstrating digital technology's central role in the global political economy and connecting it to the rise of worldwide financial, production and military networks, Schiller sets the digital communication industry in the context of intensifying geopolitical conflicts over the Internet. As he shows, the forces at the core of capitalism--exploitation, commodification, and inequality--are ongoing and accelerating within the networked political economy. Timely and wide ranging, Digital Depression blazes new ground in illuminating the role of information and communications within the political economy's developmental processes.
We investigated the epidemiology of extrapulmonary tuberculosis (TB) among patients admitted to Beijing Chest Hospital, Beijing, China, during January 2008-December 2017. Of 19,279 hospitalized TB ...patients, 33.4% (6,433) had extrapulmonary TB and 66.6% (12,846) had pulmonary TB. The most frequent forms of extrapulmonary TB observed were skeletal TB (41.1%) and pleural TB (26.0%). Younger, female patients from rural areas were more likely to have extrapulmonary TB. However, patients with diabetes mellitus were less likely to have extrapulmonary TB compared with patients without diabetes. A higher proportion of multidrug-resistant (MDR) TB was observed among patients with extrapulmonary TB than among patients with pulmonary TB. We observed a large increase in MDR TB, from 17.3% to 35.7%, for pleural TB cases. The increasing rate of drug resistance among extrapulmonary TB cases highlights the need for drug susceptibility testing and the formulation of more effective regimens for extrapulmonary TB treatment.
Balancing the banks Dewatripont, Mathias; Rochet, Jean-Charles; Tirole, Jean ...
2010., 20100419, 2010, 2010-04-19, 20100101
eBook
The financial crisis that began in 2007 in the United States swept the world, producing substantial bank failures and forcing unprecedented state aid for the crippled global financial system. ...Bringing together three leading financial economists to provide an international perspective, Balancing the Banks draws critical lessons from the causes of the crisis and proposes important regulatory reforms, including sound guidelines for the ways in which distressed banks might be dealt with in the future.
Earthquakes increase landslide susceptibility in post-seismic periods. The time required for restoring pre-earthquake susceptibility levels is defined as landslide recovery time. Overall, stronger ...earthquakes are associated with relatively long recovery times in the literature. However, the seismic effect does not explain the whole process. This paper provides insight into factors governing this process. We hypothesize that the dominant post-seismic landsliding process (i.e., new or remobilized landslides), which is governed by the interactions between co-seismic landslide deposits and seismotectonic, morphologic and climatic conditions of a site, is the key to understand the physics behind the landslide recovery time. To test this argument, we analyze 11 earthquake-affected areas associated with seismic variables (i.e., earthquake magnitude and peak ground acceleration) and four environmental factors: (1) the fraction of area affected by co-seismic landslides (FAAL), (2) local relief, (3) average daily precipitation of extreme events (mm/day) and (4) rainfall seasonality. Our findings show that in areas with limited co-seismic landslide deposits (FAAL <~1%) or not enough local relief (<300 m) allowing co-seismic materials to be deposited on hillslopes, then the recovery processes are mostly controlled by new landslides caused by strength reduction of hillslope materials. This mostly results in a relatively quick recovery (<~1 year), which is also correlated with the seasonality of precipitation. The prolonged precipitation makes the recovery process quicken. If the predisposing factors create large co-seismic landslide deposits on hillslopes (FAAL > ~1%), then remobilization of material takes the role of the dominant mechanism and recovery may take longer than a year.
•Landslide recovery is controlled by the dominant post-seismic landsliding process.•The recovery occurs via new landslides if co-seismic landslide deposits are limited.•The recovery of new landslides could occur <1 year depending on climatic conditions.•Remobilization governs the recovery if co-seismic deposits are abundant.•The longest recovery times occur via remobilization in high relief areas.
This study examines the effect of corporate social responsibility (CSR) decoupling on firm value across firms that understate versus overstate CSR. We also analyze the moderating impact of a firm's ...regulatory environment on the relationship between CSR decoupling and firm value. Using longitudinal analysis across 20 developed countries for the period 2008–2016 and employing a Bayesian item response theory method to measure CSR performance, we find that overstating CSR increases firm value whereas understating CSR decreases firm value. Our results also show that firms that overstate their CSR saw a reduction in firm value when the regulatory environment is included as a moderator.
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