RICERCA ITALIANA     

Integrated Airborne and Wireless Sensor Network systems for landslide monitoring

Università degli Studi di Bologna

Abstract

The main objective of the proposed mutidisciplinary project is to study and control slow-moving landslides by means of integrated monitoring tools with strong innovative character (wireless sensor network, airborne laser-scanning and hyperspectral survey).

Economical losses due to landslides are quite impressive in Italy. During the last 50 years, direct costs add up to 1-2 billion Euro per year (1.5 per thousand of GDP) and rise to 3-4 per thousand of GDP if indirect costs are accounted for (productivity losses, estate depreciation). Based upon these figures of economical consequences, Italy ranks first in Europe and second in the world behind Japan.

Many of the areas classified at high landslide risk, according to the regulation 267/98, are represented by large earth slides or earth flows whose last reactivation dates back to historical to recent times. The occurrence of such phenomena is ruled by complex natural processes which makes troublesome any quantitative hazard assessment based upon temporal probability and expected magnitude. In such context, slope monitoring constitute a precious tool which can be helpful for controlling the evolution of the instability phenomena through its various stages and preventing major risks. Conventional monitoring techniques are usually represented by expensive instruments whose pointwise nature can hardly cope with large landslides and for which data sharing is not straightforward.

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Principal Investigator

Matteo Berti Università degli Studi di BOLOGNA

Research Objectives

11.1 Statement of the problem.

The project aims to improve our capacity to prevent and control the evolution of slow moving large landslides by means of the development and testing of innovative low-cost monitoring solutions.

The efforts will focus on earthslides and earthflows typically involving shale and flysch formations outcropping along the apenninic mountain chain. Very often such phenomena cover large areas (few km2) and involve huge masses (over 100 m of thickness) of soil and rock which reactivate periodically with a complex style of activity. They rarely constitute a threat to human life due to slow to moderate velocities but economical and social consequences are quite high. Active mitigation measures seldom represent a viable option due to prohibitive costs deriving from the large volumes at play (millions of m3).

The evolution dynamics of large apenninic landslides is ruled by multiple factors whose interaction determines the hystory of deformations and the periodic approach to failure conditions. The fundamental role of the slope hydrologic response to climatic forcing combines with processes acting at different time-scale such as weathering of geo-materials and progressive failure. The uncertainties deriving from the representation of such processes and prediction of their combined effects reflect upon the substantial impossibility of producing a reliable quantitative hazard assessment. Any risk mitigation strategy >>>

First Results

15.1 Predicted results

The overall expected result is a much improved capacity of measuring and understanding the processes governing the time-dependent behaviour of large slow-moving landslides. Innovative monitoring techniques will be pivotal in the proposed research and their potential in the ambit of risk prevention and mitigation strategies will be explored. The experimentation will be carried out in two experimental sites where conventional monitoring systems are already operating. Preliminary tests already took place at the time of writing. They demonstrate, we believe, the soundness of the experimental program proposed.
More particularly, specific expected results can be listed as follows:

1. Completion of the experimental set up in the two representative landslides where traditional monitoring devices will be integrated within wireless sensor networks;
2. Development of advanced algorithms for optimization of WSN infrastructures, reduction of power consumption, prolongation of operating capabilities and adaptive data sampling.
3. Development of processing techniques for airborne data (Lidar, hyperspectral, ALTM) for topographic roughness analysis and strain-rate maps.
4. Web 2.0 platform for integration and publication of experimental data.
5. Advancement of our knowledge and capacity of predicting the hydrological response of large unstable slopes with particular reference to the propagation of >>>

Timescale

24 months

National and international background

In the last decades, quantitative methods for landslide hazard assessment received an ever growing attention (Fell, 1994; Hutchinson, 1995; Einstein, 1997; Guzzetti et al., 2005). This is mainly due to the raising awareness of the problem in the community and the decreased willing to dwell with natural risks. The problem is of major relevance in our country, where the ratio damage/PIL with respect to mass wasting phenomena is ranking first in Europe and second in the World (Canuti et al., 2001).
Generally, landslide hazard assessment is aimed at identifying potentially unstable areas at a large spatial scale and at supporting decision makers in territorial planning and risk management (Varnes, 1984; UNESCO, 1993; Schuster & Kockelman, 1996; Wong et al., 1997; Lee & Jones, 2004). This important issues have led to the development of physically-based prediction methods (Montgomery & Dietrich, 1994; Wu & Sidle,1995; Borga et al., 2002; Casadei et al., 2003; Dhakal & Sidle, 2004; D'Odorico et al., 2005). These methods have been largely applied, sometimes also outside their specific geological contexts (Iverson, 2000), but the ultimate goal to attain a quantitative assessment of landslide hazard still appears to be far away.
A large number of experimental studies demonstrated the wide range of hydrogeological flow conditions as well as the inherent complexity of physical processes involved (Iverson & Major, 1987 >>>