Satellite observations have revealed that weak seismic
ground shaking can trigger powerful landslide acceleration—even
several years after a significant earthquake.
These observations help paint a comprehensive picture of landslide
behaviour triggered by seismic activity and provide the tools for
real-time monitoring to support rapid rescue operations.
Landslides, a natural geological hazard worldwide, cause serious human
and economic losses every year. Between 1998-2017, landslides affected
an estimated 4.8 million people worldwide and cause more than 18,000
deaths (estimates from WHO). Landslides can be triggered by earthquakes,
volcanoes, rainfall or human activity and the recent landslide that
tore across the Italian island of Ischia is an example of a landslide
triggered by rainfall.
Published in the journal Nature Communications, the study focussed on
earthquake-accelerated landslides (EALs). These types of landslides are
affected by the long-term seismic effects and may maintain accelerated
motion for a long time after the earthquake. EALs cause particularly
serious human casualties, especially in seismically active areas.
The research was led by Professor Zhenhong Li, presently at Chang’an
University (China), and Professor Utili at Newcastle University. They
also worked with Professors Giovanni Crosta and Paolo Frattini at the
University of Milan-Bicocca, Italy.
The scientists used satellite radar observations to detect and investigate
the activation and recovery of EALs in Central Italy. Their work has
led to the first ever complete EAL inventory, which has the potential
to inform long-term landslide risk assessment in seismically active areas.
Professor Stefano Utili, Professor of Geotechnical Engineering at Newcastle
University’s School of Engineering, said: “This work is of great
significance for long-term landslide risk assessment in areas where we
see seismic activity. People tend to think landslides triggered by
earthquakes only occur during or immediately after an earthquake, but
unfortunately an awful lot of them happen several years after the seismic
event in areas previously thought safe so it is not easy to make predictions.
This study showcases a cost-effective and efficient methodology based on
satellite imagery to identify and assess the risk posed by ground movements
becoming catastrophic landslides following an earthquake in the long term.
The next steps will be for civil authorities to adopt the methods.”
Co-author Professor Jianbing Peng, Member of Chinese Academy of
Sciences (CAS), said: “This study contributes to a comprehensive
understanding of the risk of earthquake-induced landslides, including
coseismic landslide failures and post-earthquake landslide dynamics,
and it is of great significance for the long-term assessment and
management of landslide hazards in seismically active areas.”
Provided by the IKCEST Disaster Risk Reduction Knowledge Service System