INTEGRATING INSAR AND GEOLOGIC ESTIMATES OF SLIP RATES IN CENTRAL TIBET

We use a combination of repeat-pass synthetic aperture radar interferometry (InSAR) and cosmogenic dating to characterize the slip-history along the Dong Co conjugate fault system in Central Tibet. The Dong Co conjugate fault system is centered along the E-trending Bangong-Nujiang suture zone. The conjugate fault system is comprised of the NE-striking left-slip Riganpei Co fault to the north and NW-striking right-slip Gyaring Co fault to the south. These structures accommodate a portion of Indo-Asian convergence and long term slip-rates determined along these faults indicate north-south contraction is occurring across Central Tibet at a rate of ~2 mm/yr. Preliminary interferograms were constructed using descending orbital tracks of the ERS 1 and ERS 2 European Space Agency satellites with a time-span of seven years. Surface displacement maps along the radar line of sight indicate a significant strain gradient from the NW to SE centered along the Riganpei Co fault, and is consistent with left-slip. Our preliminary InSAR results are consistent with geologic observations and suggest little variation in the near-field strain rate since about 7 ka.