Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 5 1 2005 10.5194/nhess-5-43-2005 http://www.nat-hazards-earth-syst-sci.net/5/43/2005/ http://www.nat-hazards-earth-syst-sci.net/5/43/2005/nhess-5-43-2005.html http://www.nat-hazards-earth-syst-sci.net/5/43/2005/nhess-5-43-2005.pdf 43 47 2005-01-03 Note on seismic hazard assessment using gradient of uplift velocities in the Turan block (Central Asia) M. Jaboyedoff M.-H. Derron G. M. Manby Quanterra, CH-1007 Lausanne, Switzerland Institute of Geomatics and Risk Analysis (IGAR), University of Lausanne, CH-1015 Lausanne, Switzerland Geological Survey of Norway/International Center for Geohazards, 7491 Trondheim, Norway Deartment of Earth and Environmental Sciences, University of Greenwich, Chatham Maritime, United Kingdom Uplift gradients can provide the location of highly strained zones, which can be considered to be seismic. The Turan block (Central Asia) contains zones with high gradient of uplift velocities, above the threshold 0.04mm km^-1year^-1. Some of these zones are associated with important seismic activity and others are not correlated with any recent important recorded earthquakes, however, recent faults scarps as well as diverted rivers may indicate a recent tectonic activity. This threshold of gradient is probably a significant rheologic property of the upper crust. On the basis of these considerations the Uzboy river area is proposed as a potential high seismic hazard zone.