Nepal's quake-driven landslide hazards
Large earthquakes can trigger dangerous landslides across a wide geographic region. The 2015
M
w
7.8 Gorhka earthquake near Kathmandu, Nepal, was no exception. Kargal
et al.
used remote observations to compile a massive catalog of triggered debris flows. The satellite-based observations came from a rapid response team assisting the disaster relief effort. Schwanghart
et al.
show that Kathmandu escaped the historically catastrophic landslides associated with earthquakes in 1100, 1255, and 1344 C.E. near Nepal's second largest city, Pokhara. These two studies underscore the importance of determining slope stability in mountainous, earthquake-prone regions.
Science
, this issue p.
10.1126/science.aac8353
; see also p.
147
The Himalaya, the world's highest mountain ranges, are home to a large group of glaciers and glacial lakes. Glacial lake outburst floods (GLOFs) in this region have resulted in catastrophic damages and fatalities in the past decades. The recent warming has caused dramatic glacial lake changes and increased potential GLOFs risk in the Himalaya. However, our knowledge on the current state and change of glacial lakes in the entire Himalaya is limited. This study maps the current (2015) distribution of glacial lakes across the entire Himalaya and monitors the spatially-explicit evolution of glacial lakes over five time periods from 1990 to 2015 using a total of 348 Landsat images at 30 m resolution. The results show that 4950 glacial lakes in 2015 cover a total area of 455.3 ± 72.7 km 2 , mainly located between 4000 m and 5700 m above sea level. Himalayan glacial lakes expanded by approximately 14.1% from 1990 to 2015. The changing patterns of supraglacial lakes and proglacial lakes are rather complex, involving both lake disappearance and emergence. Many emergent glacial lakes are found at higher elevations, especially the new proglacial lakes, which have formed as a result of glacier retreat. Spatially heterogeneous changes of Himalayan glacial lakes are observed, with the most significant expansion occurring in the southern slopes of the central Himalaya. Increasing glacier meltwater induced by the Himalayan atmospheric warming is a primary cause for the observed lake expansion. This study provides primary data for future GLOF risk assessments. A total of 118 rapidly expanded glacial lakes are identified as potential vulnerable lakes for the priority of risk assessment.
The meltwater released by the glaciers in the Aksu-Tarim Catchment, south of Tomur Peak (Central Tien Shan), feeds the Tarim River which is the main artery for the oases at the northern margin of the Taklamakan desert. The correct modeling of the contribution of the glaciers meltwater to the total runoff of the Tarim River is hampered by the lack of mass balance data. Multi-temporal digital terrain models (DTMs) allow the determination of volume changes for large samples of glacier. Here, we present the mass changes for 12 glaciers using 1976 KH- The meltwater released by the glaciers in the Aksu-Tarim Catchment, south of Tomur Peak (Central Tien Shan), feeds the Tarim River which is the main artery for the oases at the northern margin of the Taklamakan desert. The correct modeling of the contribution of the glaciers meltwater to the total runoff of the Tarim River is hampered by the lack of mass balance data. Multi-temporal digital terrain models (DTMs) allow the determination of volume changes for large samples of glacier. Here, we present the mass changes for 12 glaciers using 1976 KH-
Abstract. There is currently no glacial lake inventory data set for
the entire high-mountain Asia (HMA) area. The definition and classification
of glacial lakes remain controversial, presenting certain obstacles to
extensive utilization of glacial lake inventory data. This study integrated
glacier inventory data and 668 Landsat TM, ETM+, and OLI images and adopted
manual visual interpretation to extract glacial lake boundaries within a
10 km buffer from glacier extent using ArcGIS and ENVI software, normalized
difference water index maps, and Google Earth images. The theoretical and
methodological basis for all processing steps including glacial lake
definition and classification, lake boundary delineation, and uncertainty
assessment is discussed comprehensively in the paper. Moreover, detailed
information regarding the coding, location, perimeter and area, area error,
type, time phase, source image information, and subregions of the located
lakes is presented. It was established that 27 205 and 30 121 glacial lakes
(size 0.0054–6.46 km2) in HMA covered a combined area of 1806.47±2.11 and 2080.12±2.28 km2 in 1990 and 2018,
respectively. The data set is now available from the National Special
Environment and Function of Observation and Research Stations Shared Service
Platform (China): https://doi.org/10.12072/casnw.064.2019.db (Wang et al., 2019a).
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