Unraveling the links between rainfall, seismicity, landsliding, slope denudation and sediment discharge in mountain belts with the aid remotely sensed data

Project leaders

Alessandro Cesare Mondini, Hongey Chen

Agreement

TAIWAN - NSTC - National Science and Technology Council

Call

CNR/NSC 2012-2013

Department

Earth and Environment

Thematic area

Earth system science and environmental technologies

Status of the project

New

Research proposal

Taiwan, an active orogenic belt with subtropical climate is characterized by a high uplift rate and several major typhoons each year. Italy is on one of the most seismically active region in Europe because of the thrust of African plate on Eurasian continental one. Both of these tectonically active areas experienced numerous earthquakes, landslides along with intense rainfall, causing heavy damages and casualties also due to the intense urbanization and high population density.
Endogenous and exogenous processes are therefore quite active in both Countries for this reason it is of paramount importance to cooperate in the studies on such phenomena in order to better face with them and find out good strategies for disaster risk reduction.
Landslides and debris flows as well as slope denudation are important geomorphic processes in humid mountain environments worldwide and they are often considered a primary factor in the delivery of sediment budgets along the river channels. Recent studies on mechanisms of sediment supply and delivery pointed out that sediment discharge is strongly influenced by climate, topography, lithology, tectonics and human activities. Nevertheless several gaps have to be bridged in order to improve the capacity to cope with these phenomena e effectiveness of risk management activities.
Earthquakes usually represent an important triggering factor for landslides, mainly rockfall and slides. Even deep-seated gravitational slope deformations (DSGSD) and huge landslides can be triggered or reactivated by strong ground motion. In this framework Taiwan and Italy are the most suitable natural experimental fields to investigate the relationship between external triggering forces and erosion processes. Therefore, focusing the research efforts on landslide hazard assessment in seismically active regions like Taiwan and Italy seems to be a high priority issue since hazard areas are becoming more densely populated and therefore it is vital to improve our ability to live with risk.
Strong scientific relationships between Italy and Taiwan in the field of hydro-geological risk assessment already exist since more than 15 years. Several joint workshops have been organized in the past to exchange experiences and knowledge. Both the research teams are skillful in conducting studies in landslide, flood and seismic hazard utilizing the most advanced and updated techniques.

Research goals

This research project will develop an integrated methodology for assessing local and regional landslide hazard and mapping the spatial (susceptibility) and temporal probability of occurrence, based on historic landslide inventories for the investigation time period.
The working scale, the frequency of the landslide occurrence, and the inaccessibility of some area suggest the exploitation of remote sensing data and techniques both for the recognition and the monitoring of the phenomena, in addition to traditional methodologies.
Landslide recognition and mapping are proxy steps for the whole following analysis, mainly for calibration and validation of landslide susceptibility and hazard models. Recently, High Resolution and Very High Resolution satellite images have started to join aerial photographs in this task. The Multiple Change Detection (MCD) technique has shown its ability to map new landslides, old landslides and runout features of sediment deposits from debris flows. The MCD technique, in a bayesian and eventually object oriented framework, will be customized for better distinguishing geometrical features associated to different processes.
The study of earthquake triggering of landslides is an important component in hazard reduction in seismically active areas and the high level of casualties and destruction during recent events (e.g. the May 12, 2008 Wenchuan, China earthquake) remind us that further efforts are needed to reduce losses from seismically induced slope failures. There are indications from recent studies and field measurements conducted in Italy and Taiwan that seismic triggering of landslides can be facilitated by seismic site effects (local amplification and directivity phenomena). In this context the additional research proposed here on the influence of sites effects on co-seismic landsliding will lead to the improvement of regional-scale (and local-scale) assessments of seismic landslide susceptibility and hazard.
Thanks to the all-weather, day-night capability to detect and quantify accurately small ground surface deformations, Synthetic Aperture Radar (SAR) Interferometry (InSAR) techniques are attractive for landslide hazard investigations and possibly for preliminary warning. One of the objectives of this project will be to promote innovative applications of InSAR in landslide investigations by assessing the quality and practical utility of new high resolution interferometric SAR data, which are being acquired in X-band (Italian COSMO-SkyMed and German TerraSAR-X satellites) in comparison to medium resolution SAR data acquired in C-band.
Satellite radar image offers also an opportunity of routine screening and monitoring the defense structure and its surroundings affected by ongoing movement processes. High resolution, around 1m, images from COSMOS-Skymed will be available for these purposes. Further by integrating the constellation of multi-SAR systems, frequent observatio

Last update: 26/04/2024