Erwan Pathier

• Joseph Fourier University

We report a rarely observed case of steady aseismic deformation in the context of a fold-and-thrust belt, with a well-documented structural and lithological background. We focus on a 12-km-long section across the foothills of southwestern Taiwan, where about 23 mm/yr of westward compression is observed. From west to east, the surface geological str...

The Meinong earthquake generated up to ~10 cm surface displacement located 10-35 km W of the epicenter and monitored by InSAR and GPS. In addition to co-seismic deformation related to the deep earthquake source, InSAR revealed three sharp surface displacement gradients. One of them is extensional and is inconsistent with the westward interseismic s...

The Boconó fault is a strike-slip fault lying between the North Andean Block and the South American plate which has triggered at least five Mw > 7 historical earthquakes in Venezuela. The North Andean Block is currently moving toward NNE with respect to a stable South American plate. This relative displacement at ~12 mm yr−1 in Venezuela (within th...

We focus herein on the location, characterization and the quantification of the most active structural feature of Taiwan: the Longitudinal Valley Fault that corresponds to the suture in between the Philippine and Eurasian Plates. In order to determine and monitor its present inter-seismic deformation, we focus on the Pingting Terraces area, situate...

Lithology variation is known to have a major control on landslide kinematics, but this effect may remain unnoticed due to low spatial coverage during investigation. The large clayey Avignonet landslide (French Alps) has been widely studied for more than 35 years. Displacement measurements at 38 geodetic stations over the landslide showed that the s...

The coseismic surface displacement field and slip distribution at depth due to the Kashmir earthquake (Mw = 7.6, 2005) have been analysed by different authors using subpixel correlation of synthetic aperture radar (SAR) images and optical images, teleseismic analysis, GPS measurements, as well as in situ field measurements. In this paper, first, we...

Taiwan is located at the boundary between the Eurasian Plate and the Philippine Sea Plate. The Longitudinal Valley at the eastern Taiwan is considered to be the collision boundary. There are several faults in the valley and the most famous one is the Longitudinal Valley Fault (LVF) which accommodates about one third of convergence rate between thes...

This paper presents new observation of the interseismic deformation along the Longitudinal Valley (Eastern Taiwan) that represents a major tectonic boundary of the Taiwan collision zone. We investigate the southern part of the Valley from Rueisuei to Taitung (latitude 23.5°N–22.7°N), which is the part of the Valley where interseismic surface creep...

In geophysics, the uncertainty associated with model parameters or displacement measurements plays a crucial role in the understanding of geophysical phenomenon. An emerging way to reduce the geodetic parameter uncertainty is to combine a large number of data provided by SAR images. However, the measurements by radar imagery are subject to both ran...

The Longitudinal Valley fault (LVF) is an active suture between the Luzon arc of the Philippine Sea plate (PSP) and the Chinese continental margin of the Eurasian plate in eastern Taiwan. With respect to Paisha station located at stable continental margin, the stations of Coastal Range in PSP show the velocities of 40.5-72.3 mm/yr towards azimuth 3...

DInSAR has proven its potential in detecting not only large coseismic or postseismic deformation, but also small deformation signals, such as interseismic deformation. However, atmospheric phase screens are the main limitation in detecting such small deformations, and can even mask them, especially in areas of large relief. Various methods have bee...

We assemble a processing chain that handles InSAR computation from raw data to time series analysis. A large part of the chain (from raw data to geocoded un-wrapped interferograms) is based on ROI PAC modules (Rosen et al., 2004), with original routines rearranged and combined with new routines to process in series and in a common radar geometry al...

The Longitudinal Valley, located in the eastern part of Taiwan, corresponds to the suture zone between the Eurasian and Philippine Sea plates, where an active collision occurs associated to an important seismicity. A series of historical large earthquakes occurred on the Longitudinal Valley, especially in autumn 1951 with four earthquakes Ms > 7 an...

The Longitudinal Valley, located in the eastern part of Taiwan, corresponds to the suture zone between the Eurasian and Philippine Sea plates, where an active collision occurs associated to an important seismicity. A series of historical large earthquakes occurred on the Longitudinal Valley, especially in autumn 1951 with four earthquakes Ms > 7 an...

The Longitudinal Valley fault (LVF) is a plate suture fault between the Luzon arc of the Philippine Sea plate and the Chinese continental margin of the Eurasian plate in eastern Taiwan. With respect to Paisha station, S01R, the stations of Coastal Range shows the velocities of 40.5-72.3 mm/yr towards azimuth 307˚09˚he stations in the Longitudinal V...

Paleotopography in Quaternary sedimentary environments can be an important factor that controls landslide movement. This study investigates the relation between paleotopography and landslide activity in two adjacent landslides in glaciolacustrine sediments located in the Trièves area (French western Alps). Although both are in slopes underlain by t...

In this paper, 2 data fusion strategies from SAR images are investigated through application to measurement of displacement field due to the Kashmir earthquake (Mw=7.6, 2005). Firstly, the 3D displacement field at the Earth's surface is retrieved by a linear inversion, using the measurements from sub-pixel image correlation and differential interfe...

We apply both sub-pixel image correlation and differential interferometry (D-InSAR) on a series of ENVISAT images from October 2004 to June 2006 in order to map the deformation due to the Kashmir earthquake (Mw=7.6) of October 8th, 2005. The 3D surface displacement field at the Earth's surface as well as the displacement field at depth on the ruptu...

The Sichuan earthquake, Mw 7.9, struck the Longmen Shan range front, in the western Sichuan province, China, on 12 May 2008. It severely affected an area where little historical seismicity and little or no significant active shortening were reported before the earthquake (e.g. Gu et al., 1989; Chen et al., 1994; Gan et al., 2007). The Longmen Shan...

PALSAR L-band spaceborne Synthetic Aperture Radar (SAR) amplitude images are used to map the Sichuan earthquake rupture (China, M w 7.9, 12 May 2008) and to identify the faults activated by the earthquake. A sub-pixel correlation method is used to retrieve the coseismic displacement field projected into the line of sight of the satellite and the ho...

In this paper, we apply both sub-pixel image corre-lation and differential interferometry techniques on a series of ENVISAT images (ascending + descending) in order to map the surface 3D displacement field due to the Kashmir earthquake of October 8, 2005. A particular chain for phase unwrapping based on multi-scales local frequencies is developed w...

The Trièves area is located within the French alpine foreland 40 km south of the town Grenoble. This 300 km2 area is covered by a thick Quaternary clay layer (up to 200 m) deposited in a glacially dammed lake during the Würm period. After the glacier melting, rivers have cut deeply into the geological formations, triggering numerous landslides. Our...

The two large adjacent landslides of Avignonet and Harmalière, affecting thick clayey quater- nary deposits, are located in the Trièves area (French Alps). Remote techniques (Lidar) and GPS measure- ments were used to characterize the two landslides. Results show major differences between the dynamics of the two landslides, both in morphology, disp...

The large Avignonet landslide (40 × 10 6 m 3) is located in the Trieves area (French Alps) which is covered by a thick layer of glacio-lacustrine clay. The slide is moving slowly at a rate varying from 1 cm/year near the upper scarp to over 13 cm/year at the toe. A preliminary geophysical campaign was performed in order to test the sensitivity of g...

The D-InSAR technique is applied to detect the active fault-related folding structure of the Tainan tableland near the deformation front in SW Taiwan by using ERS SAR images during 1996–2000. The Tainan tableland is located in-between a blind fault in the west and the Houchiali fault in the east, thus the Tainan tableland is interpreted as a pop-up...

The 8th October 2005 Kashmir Earthquake Mw 7.6 involved primarily thrust motion on a NE-dipping fault. Sub-pixel correlation of ENVISAT SAR images gives the location of the 80 km-long fault trace (within 300–800 m) and a 3D surface displacement field with a sub-metric accuracy covering the whole epicentral area. The slip distribution inverted using...

We apply the D-InSAR technique to monitor the active growing structure on the Tainan Tableland near the deformation front in SW Taiwan using ERS SAR images in the period of 1996–2000. Interferometric processing of six SAR images reveals the average slant range displacement (SRD) to be ∼12.5 mm/yr, and it increases from the west edge of the Tainan T...

The challenge of measuring interseismic deformation across major active faults is to be able to measure small displacement rates at large spatial scale; typically, 1 cm/year or less distributed over 100 km or greater. Using InSAR techniques, difficulties come mainly from water vapor signal, orbital error and limited temporal coherence as strain acc...

Application of the interferometric method to four ERS2-SAR images acquired before and after the 1999 Chichi earthquake has allowed determination of the coseismic surface displacement in the footwall area of the Chelungpu fault. The interferometric results revealed a relative shortening in the round trip distance between the radar antenna and the gr...

Presents four case examples of contribution on InSAR to active tectonics issues in Taiwan Island that is one of the most seismically active regions in the world. For these studies, differential InSAR technique is used in a 2-pass approach, the resulting interferograms combine images of the ERS-1/2 satellites from 1993 to 2001. The results illustrat...

The differential SAR interferometry technique (interferometric synthetic aperture radar, InSAR) is applied on the Chelungpu fault surface rupture zone of the September 20, 1999, Taiwan, Chi-Chi earthquake using six ERS-2 images covering the period from February 1999 to January 2000. As compared with available geodetic data, InSAR measurements resul...

Four ERS2-SAR images acquired before and after the 1999 Chichi earthquake allow determination of the co-seismic surface displacement in the footwall area of the Chelungpu fault by SAR interferometric method. The interferometric results reveal a relative shortening in the round trip distance between the radar antenna and the ground of the footwall s...

On september 1999, the Mw = 7.6 Chi-Chi earthquake reactivated the Chelungpu fault, a major N-S trending thrust of the Taiwan Western Foothills. The rupture which developed along this east-dipping fault reached the ground surface, causing a spectac- ular 80-km-long fault scarp with plurimetric offsets. Our work based on Interferomet- ric Synthetic...

Interferometric processing of five SAR-ERS images reveals uplift of the Tainan Tableland (SW of Taiwan) during the period 1996-1998. The maximum measured ground motion for these two years is 2.8 cm along the radar line of sight towards the satellite, indicating for the displacement vector a vertical component of 3.2 cm, and a horizontal component o...

The diversity of the research in earth sciences leads to a multisource approach to investigate the surroundings of Taiwan. Various data sets combined by a Geographical Information System (GIS) enable us to propose an integrated neotectonic map of onshore-offshore Taiwan. Several technical problems arise during the compilation of this map, such as t...

The diversity of the research in earth sciences leads to a multisource approach to investigate the surroundings of Taiwan. Various data sets combined by a Geographical Information System (GIS) enable us to propose an integrated neotectonic map of onshore-offshore Taiwan.

This paper presents a study combining remote sensing and seismic prospecting for investigating two clayey landslides located in the Trièves area (Western French Alps). Although affecting similar slopes made of similar clay layer under the same meteorological conditions, the two adjacent Avignonet and Harmalière landslides exhibit, since the 1980s,...