- Email: [email protected]
Special issue from the symposium on Remote Sensing and Monitoring of Landslides
Engineering Geology 68 (2003) 1 – 2 www.elsevier.com/locate/enggeo
Preface
Special issue from the symposium on Remote Sensing and Monitoring of Landslides Potentially unstable slopes and landslides are often local scale features, even though they can occur in great numbers over a wide area. This and the limited size of many damaging or socio-economically significant mass movements require the use of observational data with much greater spatial resolution with respect to those used for other natural disasters such as floods, earthquakes, volcanic eruptions. Large scale, stereo aerial photographs have been extensively applied in landslide investigations for several decades. They are very useful for the recognition, characterisation and geomorphic analysis of landslides. Recently, there has been a considerable increase in satellite remote sensing studies for slope stability investigations. This appears to have resulted from (i) the greater data availability of several new Earth Observation (EO) satellite systems in the last decade (e.g. European ERS-1 and ERS-2 satellites, SIR-C/X-Synthetic Aperture Radar flown onboard of NASA’s Space Shuttle, Japanese JERS-1, Canadian RADARSAT, United States LANDSAT TM 5 and 7, and the French SPOT and Indian IRS satellites); (ii) the improved capabilities (high resolution, stereo and frequent revisits) of the optical and SAR satellites and (iii) the development of more advanced EO data processing techniques. Significant challenges persist regarding the practical applicability of EO data to landslide investigations. The single and most important factor, which limits the utility of many currently available EO satellite datasets, is the coarse resolution of space imagery. The most recent deployments of new, more sophisticated satellite systems (e.g. commercial satellite IKONOS in 1999, QUICKBIRD in 2002, European ENVISAT in 2002), as well as the future satellite
launches (e.g. Canadian RADARSAT 2), hold the premise for ever increasing use of EO data in landslide investigations. This special issue of Engineering Geology contains a selection of papers presented at the symposium on ‘‘Remote Sensing and Monitoring of Landslides’’ held at the European Geophysical Society XXVI General Assembly in Nice, France, in March 2001. Geologists, engineers and physicists from several countries contributed current research on the remote sensing of landslides in different environmental settings throughout the world. This symposium was intended to: firstly, provide an overview of the advantages and limitations of ‘‘traditional’’ air- and space-borne data for landslide recognition/mapping, characterisation and monitoring; secondly, focus on innovative applications of state of the art technology in earth observation and image analysis for improved monitoring of landsliderelated ground deformations. It was also hoped that the session would help to (a) make users more familiar with some inherent limitations of space observation systems and relevant data processing techniques, and (b) make remote sensing specialists more aware of a great diversity of slope failures (in terms of form, size, causative and triggering factors, pre-monitory signs, mechanisms, post-failure evolution), and therefore, of a considerable complexity of user requirements. The presentations covered a wide spectrum of the remote sensing techniques used in slope instability investigations. In particular, the applications of the following methods were presented: – Permanent Scatteres (PS) technique, a high precision innovative approach to surface deforma-
0013-7952/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 1 3 - 7 9 5 2 ( 0 2 ) 0 0 1 9 4 - 1
2
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Preface
tion monitoring using Synthetic Aperture Radar (SAR) data (from ERS-1 and ERS-2 imagery); Space-borne SAR conventional differential interferometry (DInSAR) using ERS-1 and ERS-2 data); Ground-based ‘‘portable’’ SAR system characterised by high spatial resolution and high precision monitoring; Integrated use of the LANDSAT 7 imagery and RADARSAT-1 data; Integrated use of digital photogrammetry, static and kinematic GPS observations.
All these topics are covered by the papers included in this special volume. The first set of papers is concerned primarily with the exploitation of SAR data acquired from space-borne and ground-based systems in landslide investigations. The second set of papers explores more conventional applications, in which information derived from air-flown sensors (digital phtogrammetry) and from space (GPS— Global Positioning Systems) is in some case studies integrated. The papers provide a wealth of information on what is currently feasible, what are the most significant limitations and what are the important future challenges. It is hoped that by bringing together a diverse spectrum of current research and applications, we have been able to demonstrate that slope stability investigations may benefit most from an interdisciplinary approach which integrates different, ade-
quately ground truthed remotely sensed data and techniques. As guest editors of this volume, we thank all the participants in the symposium and the European Geophysical Society and the Natural Hazards Working Group for providing the opportunity to organise the symposium. We are grateful to Marcel Arnould, Editor-in Chief of Engineering Geology, for accepting the proposal to publish this special issue. Reviews by colleagues from Austria, Canada, France, Italy and the United States helped to improve the contributions to this volume and are much appreciated. The editorial efforts were in part supported by the Italian National Research Council (JW), and the Canada Centre for Remote Sensing (VS). Janusz Wasowski * CNR-IRPI Sezione di Bari, c/o Politecnico di Bari, via Orabona, 4, Bari 70125, Italy E-mail address: [email protected] Vernon Singhroy Canada Centre for Remote Sensing, 588 Booth St., Ottawa, Canada K1A0Y7 E-mail address: [email protected] 26 July 2002
* Corresponding author. Fax: +39-080-556-7944.
Preface
Special issue from the symposium on Remote Sensing and Monitoring of Landslides Potentially unstable slopes and landslides are often local scale features, even though they can occur in great numbers over a wide area. This and the limited size of many damaging or socio-economically significant mass movements require the use of observational data with much greater spatial resolution with respect to those used for other natural disasters such as floods, earthquakes, volcanic eruptions. Large scale, stereo aerial photographs have been extensively applied in landslide investigations for several decades. They are very useful for the recognition, characterisation and geomorphic analysis of landslides. Recently, there has been a considerable increase in satellite remote sensing studies for slope stability investigations. This appears to have resulted from (i) the greater data availability of several new Earth Observation (EO) satellite systems in the last decade (e.g. European ERS-1 and ERS-2 satellites, SIR-C/X-Synthetic Aperture Radar flown onboard of NASA’s Space Shuttle, Japanese JERS-1, Canadian RADARSAT, United States LANDSAT TM 5 and 7, and the French SPOT and Indian IRS satellites); (ii) the improved capabilities (high resolution, stereo and frequent revisits) of the optical and SAR satellites and (iii) the development of more advanced EO data processing techniques. Significant challenges persist regarding the practical applicability of EO data to landslide investigations. The single and most important factor, which limits the utility of many currently available EO satellite datasets, is the coarse resolution of space imagery. The most recent deployments of new, more sophisticated satellite systems (e.g. commercial satellite IKONOS in 1999, QUICKBIRD in 2002, European ENVISAT in 2002), as well as the future satellite
launches (e.g. Canadian RADARSAT 2), hold the premise for ever increasing use of EO data in landslide investigations. This special issue of Engineering Geology contains a selection of papers presented at the symposium on ‘‘Remote Sensing and Monitoring of Landslides’’ held at the European Geophysical Society XXVI General Assembly in Nice, France, in March 2001. Geologists, engineers and physicists from several countries contributed current research on the remote sensing of landslides in different environmental settings throughout the world. This symposium was intended to: firstly, provide an overview of the advantages and limitations of ‘‘traditional’’ air- and space-borne data for landslide recognition/mapping, characterisation and monitoring; secondly, focus on innovative applications of state of the art technology in earth observation and image analysis for improved monitoring of landsliderelated ground deformations. It was also hoped that the session would help to (a) make users more familiar with some inherent limitations of space observation systems and relevant data processing techniques, and (b) make remote sensing specialists more aware of a great diversity of slope failures (in terms of form, size, causative and triggering factors, pre-monitory signs, mechanisms, post-failure evolution), and therefore, of a considerable complexity of user requirements. The presentations covered a wide spectrum of the remote sensing techniques used in slope instability investigations. In particular, the applications of the following methods were presented: – Permanent Scatteres (PS) technique, a high precision innovative approach to surface deforma-
0013-7952/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 1 3 - 7 9 5 2 ( 0 2 ) 0 0 1 9 4 - 1
2
–
–
– –
Preface
tion monitoring using Synthetic Aperture Radar (SAR) data (from ERS-1 and ERS-2 imagery); Space-borne SAR conventional differential interferometry (DInSAR) using ERS-1 and ERS-2 data); Ground-based ‘‘portable’’ SAR system characterised by high spatial resolution and high precision monitoring; Integrated use of the LANDSAT 7 imagery and RADARSAT-1 data; Integrated use of digital photogrammetry, static and kinematic GPS observations.
All these topics are covered by the papers included in this special volume. The first set of papers is concerned primarily with the exploitation of SAR data acquired from space-borne and ground-based systems in landslide investigations. The second set of papers explores more conventional applications, in which information derived from air-flown sensors (digital phtogrammetry) and from space (GPS— Global Positioning Systems) is in some case studies integrated. The papers provide a wealth of information on what is currently feasible, what are the most significant limitations and what are the important future challenges. It is hoped that by bringing together a diverse spectrum of current research and applications, we have been able to demonstrate that slope stability investigations may benefit most from an interdisciplinary approach which integrates different, ade-
quately ground truthed remotely sensed data and techniques. As guest editors of this volume, we thank all the participants in the symposium and the European Geophysical Society and the Natural Hazards Working Group for providing the opportunity to organise the symposium. We are grateful to Marcel Arnould, Editor-in Chief of Engineering Geology, for accepting the proposal to publish this special issue. Reviews by colleagues from Austria, Canada, France, Italy and the United States helped to improve the contributions to this volume and are much appreciated. The editorial efforts were in part supported by the Italian National Research Council (JW), and the Canada Centre for Remote Sensing (VS). Janusz Wasowski * CNR-IRPI Sezione di Bari, c/o Politecnico di Bari, via Orabona, 4, Bari 70125, Italy E-mail address: [email protected] Vernon Singhroy Canada Centre for Remote Sensing, 588 Booth St., Ottawa, Canada K1A0Y7 E-mail address: [email protected] 26 July 2002
* Corresponding author. Fax: +39-080-556-7944.