Using differential SAR interferometry to map land subsidence: a case study in the Pingtung Plain of SW Taiwan

O R I G I N A L P A P E R

Using differential SAR interferometry to map land

subsidence: a case study in the Pingtung Plain

of SW Taiwan

Chia-Sheng Hsieh

_{Tian-Yuan Shih}

_{Jyr-Ching Hu}

_{Hsin Tung}

Mong-Han Huang

_{Jacques Angelier}

Received: 10 July 2009 / Accepted: 27 January 2011 / Published online: 18 February 2011 Ó Springer Science+Business Media B.V. 2011

Abstract

Synthetic aperture radar (SAR) interferometry (InSAR) is a geodetic tool

widely applied in the studies of earth-surface deformation. This technique has the benefits

of high spatial resolution and centimetre-scale accuracy. Differential SAR interferometry

(DInSAR) is used to measure ground deformation with repeat-pass SAR images. This

study applied DInSAR and persistent scatterers InSAR (PSInSAR) for detecting land

subsidence in the Pingtung Plain, southern Taiwan, between 1995 and 2000. In recent

years, serious land subsidence occurred along coastal regions of Taiwan as a consequence

of over-pumping of underground water. Results of this study revealed that the critical

subsidence region is located on the coast near the estuary of Linpien River. It is also found

that subsidence was significantly higher during the dry season than the wet season. The

maximum annual subsidence rate of the dry season is up to -11.51 cm/year in critical

subsidence region and the vertical land movement rate is much slower during the wet

season. The average subsidence rates in wet and dry seasons are -0.31 and -3.37 cm/year,

respectively. As a result, the subsidence rate in dry seasons is about 3 cm larger than in wet

seasons.

Keywords

SAR inteferometry

 DInSAR  PSInSAR  Land subsidence  Pingtung Plain

C.-S. Hsieh

Department of Civil Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung, Taiwan

T.-Y. Shih (&)

Department of Civil Engineering, National Chiao-Tung University, Hsinchu, Taiwan e-mail: tyshih@mail.nctu.edu.tw

J.-C. Hu H. Tung

Department of Geosciences, National Taiwan University, Taipei, Taiwan M.-H. Huang

Berkeley Seismological Laboratory, University of California, Berkeley, CA, USA J. Angelier

Observatoire Oce´anologique de Villefranche, Ge´osciences Azur, Villefranche-sur-Mer, France DOI 10.1007/s11069-011-9734-7

1 Introduction

The interferometric synthetic aperture radar (InSAR) technique allows generation of

high-precision digital terrain data over a broad area, resulting in the production of digital

elevation model (DEM). The differential SAR interferometry (DInSAR) technique can be

used to determine earth-surface displacement and detect deformation arising from land

subsidence, earthquakes, volcanoes, or others (Massonnet and Feigl

1998

; Bu¨rgmann et al.

2000

; Zebker

2000

). In addition to mandatory corrections of various effects related to

orbital and climatic characteristics, the resulting DInSAR interferograms may be affected

by poor image coherence caused by abrupt terrain and dense vegetation, a dire concern in

Taiwan. However, several successful studies have already validated this method and

mapped the Earth’s surface deformation in Taiwan, including the studies regarding the

uplift of the Tainan tableland (Fruneau et al.

2001

; Huang et al.

2006

) and the co-seismic

deformation of the footwall block of the Chelungpu Fault during the 1999 Chi–Chi

earthquake (Pathier et al.

2003

; Chang et al.

2004b

; Hsieh and Shih

2006

).

Geodetic measurements using the global positioning system (GPS) and differential

levelling offer high-precision control points for measuring earth-surface deformation.

However, they are in the form of either points or lines. And there is practical limitation on

the density of geodetic points. To this respect, for analysing the active deformation of a

given area, it is appropriate to integrate geodetic measurements with DInSAR, which

provides areal measurements.

The Pingtung Plain of south-western Taiwan is a fast subsidence domain with high

sedimentation rate (Hsieh et al.

2006

). These characteristics arise from the particular

tectonic setting of the area (Hu et al.

2006

,

2007

). Although human activities such as

over-pumping of ground water significantly increase the present subsidence rate (Hou et al.

2005

), the main origin of Quaternary subsidence is the extension related to lateral escape

near the southern tip of the Taiwan collision belt (Angelier et al.

2009

). Both horizontal

and vertical land movement rates are high in this area. In this study, DInSAR and PSInSAR

are applied together with GPS and levelling for further exploring land subsidence. The

result of this study reveals that it is uplifting in the northern Pingtung Plain and subsiding

in the southern Pingtung Plain. It is also found that the subsidence rate is significantly

higher in dry seasons than in wet seasons.

2 Tectonic background

As shown in Fig.

1

, Taiwan is located at the boundary between the south-east portion of

the Eurasian Plate and the Philippine Sea Plate, where the convergent rate between the

volcanic arc and continental margin is about 8.2 cm/year (Yu et al.

1997

; Lin et al.

2010

).

Because of arc–continent collision (Suppe

1984

), the island of Taiwan is the result of

active orogenic mountain building with major crustal shortening (Ho

1986

). The Pingtung

Plain is located in south-western Taiwan (Fig.

1

) and covers a nearly rectangular area of

1,210 km

. It corresponds to a major graben bounded by two large faults (Fig.

2

): the

Chaochou fault to the east (as the western boundary of the metamorphic formations of the

Central Range) and the Kaoping fault to the west (in the Late Cenozoic formations of

the Foothills). Whereas the Chaouchou fault is well exposed at the foot of high mountains,

the Kaoping fault is often buried beneath the Holocene alluvium of the Kaoping River. All

outcrops in the Pingtung Plain, as well as shallow wells (Hsieh et al.

2006

), show

sediments consist of coastal and estuarine sand and mud, with abundant shallow-marine

and lagoon shells and foraminifera (Shyu et al.

2005

). East of the Chaochou fault, the high

mountains are mainly composed of Eocene–Miocene argillite, slate and meta-sandstone.

The most significant geomorphological feature of the Pingtung Plain, easily observed from

the satellite images of Taiwan, is the straight, N–S trending Chaochou fault escarpment

that separates the alluvial plain from the high mountains (Fig.

2

). Geological,

seismo-logical and geodetic observations suggest that this Chaochou Fault is a reverse fault with a

left-lateral component (Hu et al.

1997

,

2001

,

2007

). To the north and west, the Pingtung

Plain is bounded by low hills of deformed Quaternary sediments. The Kaoping River flows

along this western edge, which corresponds to the trace of the Kaoping Fault. Geodetic

observations (Hu et al.

2006

) indicate a right-lateral component of present-day slip along

Fig. 1 Geotectonic framework and major structural units of Taiwan between the Eurasian and Philippine Sea plate. The large red arrow shows the direction and velocity of convergence between the volcanic arc and the continental margin (Yu et al.1997). Blue arrows indicate the directions of tectonic escape. The green area denotes the location of basement high, and its surrounding brown dash line indicates the 3-km-deep top of the pre-Tertiary basement (Lin et al.2003). Red domains are the Luzon volcanic arcs. Yellow triangles present the locations of local permanent GPS stations used in this study. The rectangle denotes the study area

variations in topographic surface, but because of the discontinuous spatial character of

observations, it commonly occurs that stations do not coincide with the most critical points

of maximum uplift or subsidence or fail to account for discontinuities when compared with

more gradual changes. The changes with time that we were able to identify in the southern

Pingtung Plain include the contrast between dry and wet seasons for the shortest term, as

well as an abrupt increase in subsidence between 1996 and 1999 followed by a decrease in

1998–1999. Not only did our DInSAR analysis allowed reconstruction of the temporal

evolution of vertical land movement, it also provided a detailed account of the shape of

uplift and subsidence areas, as a function of mapping of interferometric fringes.

The DInSAR analysis certainly provides an efficient tool to monitor the short-term

variations, which are partly related to the status of the water tables influenced by both the

seasonal effect and the human over-pumping. To this respect, despite large uncertainties,

we could evaluate the ratio between the pumping effect near the Earth’s surface and the

deep-seated subsidence, for the coastal area of the south-eastern Pingtung Plain where

subsidence is largest (as indicated by average subsidence rates of about ?17 mm/year for

the 1995–2005 period, when compared with an average subsidence rate of -6 mm/year

for the Holocene). The most important uncertainty in such evaluations certainly depends

on the assumption of a constant rate of deep-seated subsidence, which is subject to debate.

However, in the case of the Pingtung Plain, the geodetic (GPS) data about horizontal

displacements did not reveal large variations during the observation period (1995–2005). It

is consequently reasonable to consider that the deep-seated source of deformation did not

undergo large variations during this period, which suggests that most of the changes in

vertical motion result from underground water status, regardless of its natural or human

origin. Like the horizontal displacements, the remaining vertical land movement depends

on the tectonic factor and reflects the deformation of the upper lithosphere, which is

characterised by significant extension related to extrusion towards the south-west (Angelier

et al.

2009

; Hu et al.

2006

,

2007

). This extrusion results from lateral escape in the transition

zone between collision and subduction near the southern tip of the Taiwan mountain belt.

Acknowledgments The GPS and levelling data were provided by the Central Geological Survey and the Water Resources Agency of the Ministry of Economic Affairs.

References

Angelier J, Chang TY, Hu JC, Chang CP, Siame L, Lee JC, Deffontaines B, Chu HT, Lu CY (2009) Does extrusion occur at both tips of the Taiwan collision belt? Insights from active deformation studies in the Ilan Plain and Pingtung Plain regions. Tectonophysics 466(3–4):356–376

Berardino P, Fornaro G, Lanari R, Sansosti E (2002) A new algorithm for surface deformation monitoring based on small baseline differential SAR interferograms. IEEE Trans Geosci Remote Sens 40(11):2375–2383

Bu¨rgmann RP, Rosen A, Fielding EJ (2000) Synthetic aperture radar interferometry to measure Earth surface topography and its deformation. Ann Rev Earth Planet Sci 28:169–209

Chang CP, Chang TY, Wang CT, Kuo CH, Chen KS (2004a) Land-surface deformation corresponding to seasonal ground-water fluctuation, determining by SAR interferometry in SW Taiwan. Math Comput Simul 67(4–5):351–359

Chang CP, Wang CT, Chang TY, Chen KS, Liang LS, Pathier E, Angelier J (2004b) Application of SAR interferometry to a large thrust deformation: the 1999 Mw = 7.6 Chichi earthquake in central Taiwan. Geophys J Int 159(1):9–16

Chang CP, Yen JY, Hooper A, Chou FM, Chen YA, Hou CS, Hung WC, Lin MS (2010) Monitoring of surface deformation in northern Taiwan using DInSAR and PSInSAR techniques. Terr Atom Ocean Sci 21(3):447–461

Chen CW, Zebker HA (2000) Network approaches to two-dimensional phase unwrapping: intractability and two new algorithm. J Opt Soc Am A 17:401–414

Chiang CS, Yu HS, Chou YW (2004) Characteristics of the wedge-top depozone of the southern Taiwan foreland basin system. Basin Res 16(1):65–78

Colesanti C, Ferretti A, Prati C, Rocca F (2003) Monitoring landslides and tectonic motions with the permanent scatterers technique. Eng Geol 68(1–2):3–14

Crosetto M, Castillo M, Arbiol M (2003) Urban subsidence monitoring using radar interferometry: algo-rithms and validation. Photogram Eng Remote Sens 69(7):775–783

Ding XL, Liu GX, Li ZW, Li ZL, Chen YQ (2004) Ground subsidence monitoring in Hong Kong with satellite SAR interferometry. Photogramm Eng Remote Sens 70(10):1151–1156

Ferretti A, Prati C, Rocca F (2000) Nonlinear subsidence rate estimation using permanent scatterers in differential SAR interferometry. IEEE Trans Geosci Remote Sens 38(5):2202–2212

Ferretti A, Prati C, Rocca F (2001) Permanent scatterers in SAR interferometry. IEEE Trans Geosci Remote Sens 39(1):8–20

Fruneau B, Pathier E, Raymond D, Deffontaines B, Lee CT, Wang HT, Angelier J, Rudant JP, Chang CP (2001) Uplift of Tainan Tableland (SW Taiwan) revealed by SAR interferometry. Geophys Res Lett 28(16):3071–3074

Gabriel AK, Goldstein RM, Zebker HA (1989) Mapping small elevation changes over large areas: differ-ential radar interferometry. J Geophys Res 94(B7):9183–9191

Gens R, Genderen JLV (1996) SAR Interferometry: issues, techniques, applications. Intl J Remote Sens 17(10):1803–1836

Ho CS (1986) A synthesis of the geological evolution of Taiwan. Tectonophysics 125(1–3):1–16 Hooper A, Zebker H, Segall P, Kampes B (2004) A new method for measuring deformation on volcanoes

and other natural terrains using InSAR persistent scatterers. Geophys Res Lett 31(23):L23611, 1–5 Hou CS, Hu JC, Shen LC, Wang JS, Chen CL, Lai TC, Huang C, Yang YR, Chen RF, Chen YG, Angelier J

(2005) Estimation of subsidence using GPS measurements, and related hazard: the Pingtung Plain, southwestern Taiwan. Comptes Rendus Geosci 337(13):1184–1193

Hsieh CS, Shih TY (2006) Coseismic deformation of Chi–Chi earthquake as detected by differential synthetic aperture radar interferometry and GPS data. Terr Atmos Ocean Sci 17(3):517–532 Hsieh ML, Lai TH, Wu LC, Lu WC, Liu HT, Liew PM (2006) Eustatic sea-level change of 11–5 ka in

western Taiwan, constrained by radiocarbon dates of core sediments. Terr Atmos Ocean Sci 17(2):353–370

Hu JC, Angelier J, Yu SB (1997) An interpretation of the active deformation of southern Taiwan based on numerical simulation and GPS studies. Tectonophysics 274(1–3):145–169

Hu JC, Yu SB, Angelier J, Chu HT (2001) Active deformation of Taiwan from GPS measurements and numerical simulations. J Geophys Res 106:2265–2280

Hu JC, Chu HT, Hou CS, Lai TH, Chen RF, Nien PF (2006) The contribution to tectonic subsidence by groundwater abstraction in the Pingtung area, southwestern Taiwan as determined by GPS measure-ments. Quarter Int 147(1):62–69

Hu JC, Hou CS, Shen LC, Chan YC, Chen RF, Huang C, Rau RJ, Chen HH, Lin CW, Huang MH, Nien PF (2007) Fault activity and lateral extrusion inferred from velocity Weld revealed by GPS measurements in the Pingtung area of southwestern Taiwan. J Asian Earth Sci 31(3):287–302

Huang MH, Hu JC, Hsieh CS, Ching KE, Rau RJ, Pathier E, Fruneau B, Deffontaines B (2006) A growing structure near the deformation front in SW Taiwan as deduced from SAR interferometry and geodetic observation. Geophys Res Lett 33:L12305. doi:10.1029/2005GL025613

Huang MH, Hu JC, Ching KE, Rau RJ, Hsieh CS, Pathier E, Fruneau B, Deffontaines B (2009) Active deformation of Tainan Tableland of southwestern Taiwan based on geodetic measurements and SAR interferometry. Tectonophysics 466(3–4):322–344. doi:10.1016/j.tecto.2007.11.020

Industrial Technology Research Institute (1998) Land subsidence motoring with differential levelling—the coastal area of Pingtong county. Tech. Rep., Water Resources Agency, Ministry of Economic Affairs, Taipei, Taiwan, p 46

Kampes BM (2005) Radar interferometry: persistent scatterer technique. Springer, Germany

Klees R, Massonnet D (1998) Deformation measurements using SAR interferometry: potential and limi-tations. Geologie En Mijnbouw Neth J Geosci 77(2):161–176

Kuo CH, Chan YC, Wang CH (2001) Subsidence: over withdrawal groundwater, tectonic or both? EOS, Trans AGU 82(47) Fall Meet. Suppl. Abstract H42D-0401

Lai CH, Hsieh ML, Liew PM, Chen YG (2002) Holocene rock uplift and subsidence in the coastal area of Taiwan. EOS, Trans AGU 83(47) Fall Meet. Suppl. Abstract T61B-1273

Lin AT, Watts AB, Hesselbo SP (2003) Cenozoic stratigraphy and subsidence history of the South China Sea margin in the Taiwan region. Basin Res 15(4):453–478

Lin KC, Hu JC, Ching KE, Angelier J, Rau RJ, Yu SB, Tsai CH, Shin TC, Huang MH (2010) GPS crustal deformation, strain rate and seismic activity after the 1999 Chi–Chi earthquake in Taiwan. J Geophys Res 115:B07404

Massonnet D, Feigl KL (1998) Radar interferometry and its application to changes in the earth surface. Rev Geophys 36(4):441–500

Massonnet D, Feigl K, Rossi M, Adragna F (1994) Radar interferometric mapping of deformation in the year after the Landers earthquake. Nature 369:227–230

Pathier E, Fruneau B, Deffontaines B, Angelier J, Chang CP, Yu SB, Lee CT (2003) Coseismic dis-placements of the footwall of the Chelungpu fault caused by the 1999, Taiwan Chi–Chi earthquake from InSAR and GPS data. Earth Planet Sci Lett 1–2(16):73–88

Peyret M, Rolandone F, Dominguez S, Djamour Y, Meyer B (2008) Source model for the Mw 6.1, 31 March 2006, Chalan–Chulan earthquake (Iran) from InSAR. Terra Nova 20(2):126–133

Rosen PA, Hensley S, Joughin IR, Li FK, Madsen SN, Rodriguez E, Goldstein RM (2000) Synthetic aperture radar interferometry. Proc IEEE 88(3):333–382

Shen LC, Hou CS, Hu JC, Chan YC, Huang C, Lai TC, Lin CW (2003) GPS measurements of active structure in Pingtung area, southwestern Taiwan. Spec Publ Cent Geol Surv 14:165–176

Shyu JBH, Sieh K, Chen YG, Liu CS (2005) Neotectonic architecture of Taiwan and its implications for future large earthquakes. J Geophys Res 110:B08402. doi:10.1029/2004JB003251

Stevens NF, Wadge G (2004) Towards operational repeat-pass SAR interferometry at active volcanoes. Nat. Hazards 33:47–76

Suppe J (1984) Kinematics of arc-continent collision, flipping of subduction and back-arc spreading near Taiwan. Memoir Geol Soc China 6:21–33

Tung H, Hu JC (2011) Assessments of series anthropogenic land subsidence in Yunlin County of central Taiwan from 1996 to 1999 by Persistent Scatterers InSAR. (Submitted to Tectonophysics) Yu SB, Chen HY, Kuo LC (1997) Velocity field of GPS stations in the Taiwan area. Tectonophysics

274(1–3):41–59

Zebker HA (2000) Studying the Earth with interferometric radar. Comput Sci Eng 2(3):52–60

Zebker HA, Villasenor J (1992) Decorrelation in interferometric radar echoes. IEEE Trans Geosci Remote Sens 30(5):950–959

Zebker HA, Rosen PA, Goldstien RM, Gabriel A, Werner CL (1994) On the derivation of co-seismic displacement fields using differential radar interferometry: the Landers earthquake. J Geophys Res 99(B10):19617–19634