The 2003 Bam, Iran earthquake: what we knew, what we didn’t know and what we expect in the future


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The 2003 Bam, Iran earthquake: what we knew, what we didn’t know and what we expect in the future

  • Gareth Funning (University of California, Berkeley) with Eric Fielding (JPL), James Jackson (Cambridge), Barry Parsons & Richard Walker (Oxford), Morteza Talebian (Geological Survey of Iran)




26th December 2003, Mw 6.6

  • Death toll 26,000



Tectonic setting



Tectonic setting

  • SRTM shaded-relief topography



Tectonic setting

  • SRTM shaded-relief topography



Tectonic setting

  • SRTM shaded-relief topography



Tectonic setting

  • SRTM shaded-relief topography



The Bam fault

  • LANDSAT-7 ETM 541 false colour green=vegetation





The Bam fault

  • Post-earthquake field surveys found only minor cracking at the foot of the ridge…



Preliminary InSAR data

  • First Bam interferogram (each colour cycle=2.8cm of deformation)

  • Constructed from Envisat ASAR data released for free by ESA



The Bam earthquake main fault

  • Interferometric coherence

  • Red = high

  • Blue = low

  • Constructed from Envisat ASAR data released for free by ESA



The Bam earthquake main fault

  • Surface rupture found in the field – right-lateral offsets of ~20 cm



The Bam earthquake main fault

  • Surface rupture found in the field – right-lateral offsets of ~20 cm



The Bam earthquake main fault

  • LANDSAT-7 ETM 541 false colour green=vegetation



Coseismic interferograms



Single fault model

  • Strike 354 dip 84 rake -177 slip 2.2m length 12km top 1.1km b’m 9.3km



Single fault model

  • Large residuals, especially in SE quadrant (rms = 25 mm)



Two fault model (uniform slip)



Two fault model (uniform slip)

  • Improved fit in SE quadrant (rms = 17 mm)



Two fault model (uniform slip)

  • LANDSAT-7 ETM 541 false colour green=vegetation









Aftershock distribution

  • Seismogenic crust may extend ~10 km below the rupture



Strong motions & directivity



Deformation is continuing

  • Fault zone collapse and postseismic uplift resolved with InSAR



The Bam earthquake: findings



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