Shallow fault-zone dilatancy recovery after the 2003 Bam earthquake in Iran

被引:92
作者
Fielding, Eric J. [1 ]
Lundgren, Paul R. [1 ]
Buergmann, Roland [2 ]
Funning, Gareth J. [3 ]
机构
[1] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA
[2] Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA
[3] Univ Calif Riverside, Dept Earth Sci, Riverside, CA 92521 USA
关键词
DEFORMATION; PARKFIELD; VELOCITY; DAMAGE; SLIP;
D O I
10.1038/nature07817
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Earthquakes radiate from slip on discrete faults, but also commonly involve distributed deformation within a broader fault zone, especially near the surface. Variations in rock strain during an earthquake are caused by heterogeneity in the elastic stress before the earthquake, by variable material properties and geometry of the fault zones, and by dynamic processes during the rupture(1,2). Stress changes due to the earthquake slip, both dynamic and static, have long been thought to cause dilatancy in the fault zone that recovers after the earthquake(3-5). Decreases in the velocity of seismic waves passing through the fault zone due to coseismic dilatancy have been observed(6) followed by postseismic seismic velocity increases during healing(5,7,8). Dilatancy and its recovery have not previously been observed geodetically. Here we use interferometric analysis of synthetic aperture radar images to measure postseismic surface deformation after the 2003 Bam, Iran, earthquake and show reversal of coseismic dilatancy in the shallow fault zone that causes subsidence of the surface. This compaction of the fault zone is directly above the patch of greatest coseismic slip at depth. The dilatancy and compaction probably reflects distributed shear and damage to the material during the earthquake that heals afterwards. Coseismic and postseismic deformation spread through a fault zone volume may resolve the paradox of shallow slip deficits for some strike-slip fault ruptures(9).
引用
收藏
页码:64 / 68
页数:5
相关论文
共 30 条
[1]   Characterization of fault zones [J].
Ben-Zion, Y ;
Sammis, CG .
PURE AND APPLIED GEOPHYSICS, 2003, 160 (3-4) :677-715
[2]   A new algorithm for surface deformation monitoring based on small baseline differential SAR interferograms [J].
Berardino, P ;
Fornaro, G ;
Lanari, R ;
Sansosti, E .
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, 2002, 40 (11) :2375-2383
[3]   Synthetic aperture radar interferometry to measure Earth's surface topography and its deformation [J].
Bürgmann, R ;
Rosen, PA ;
Fielding, EJ .
ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, 2000, 28 :169-209
[4]   Rheology of the lower crust and upper mantle:: Evidence from rock mechanics, geodesy, and field observations [J].
Burgmann, Roland ;
Dresen, Georg .
ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, 2008, 36 (36) :531-567
[5]   Network approaches to two-dimensional phase unwrapping: intractability and two new algorithms [J].
Chen, CW ;
Zebker, HA .
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, 2000, 17 (03) :401-414
[6]   Three-dimensional deformation caused by the Bam, Iran, earthquake and the origin of shallow slip deficit [J].
Fialko, Y ;
Sandwell, D ;
Simons, M ;
Rosen, P .
NATURE, 2005, 435 (7040) :295-299
[7]   Surface displacements and source parameters of the 2003 Bam (Iran) earthquake from Envisat advanced synthetic aperture radar imagery [J].
Funning, GJ ;
Parsons, B ;
Wright, TJ ;
Jackson, JA ;
Fielding, EJ .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 2005, 110 (B9) :1-23
[8]   Coupled evolution of damage and porosity in poroelastic media: theory and applications to deformation of porous rocks [J].
Hamiel, Y ;
Lyakhovsky, V ;
Agnon, A .
GEOPHYSICAL JOURNAL INTERNATIONAL, 2004, 156 (03) :701-713
[9]   Frictional afterslip following the 2005 Nias-Simeulue earthquake, Sumatra [J].
Hsu, Ya-Ju ;
Simons, Mark ;
Avouac, Jean-Philippe ;
Galetzka, John ;
Sieh, Kerry ;
Chlieh, Mohamed ;
Natawidjaja, Danny ;
Prawirodirdjo, Linette ;
Bock, Yehuda .
SCIENCE, 2006, 312 (5782) :1921-1926
[10]   Seismotectonic, rupture process, and earthquake-hazard aspects of the 2003 December 26 Bam, Iran, earthquake [J].
Jackson, J. ;
Bouchon, M. ;
Fielding, E. ;
Funning, G. ;
Ghorashi, M. ;
Hatzfeld, D. ;
Nazari, H. ;
Parsons, B. ;
Priestley, K. ;
Talebian, M. ;
Tatar, M. ;
Walker, R. ;
Wright, T. .
GEOPHYSICAL JOURNAL INTERNATIONAL, 2006, 166 (03) :1270-1292