Faults in the Earth's crust behave in ways that are far from fully understood. Three invited speakers in Session GD09/G13, Annemarie Bos, Götz Bokelmann and Anke Friedrich present great new advances in understanding how the crust responds to the forces acting upon it. Their work may have important applications in earthquake prediction.

Annemarie Bos and co-workers developed a new method of analyzing the stress build-up of a region from GPS surface deformation data. Their new approach is to subtract the stress released by seismicity from the total stress, a quantity which they dubbed "deficit strain". They applied their new method to the southwestern US, in a study of the Northridge, Landers and Loma Prieta earthquakes. One of the advantages of the deficit strain method is that it can identify areas where stress has built up, so far undetected, which could be released as major earthquakes. For the first time, they applied this method to the Izmit earthquake and simultaneously analyzed the surface deformation, stress build-up and fault movement. In their analysis the earthquake source showed two phases, with different intensities on either side of the Northern Anatolian Fault. This explains why damage was greater to the east of the earthquake than west of it.

In an analysis of the Loma Prieta earthquake Götz Bokelmann and co-workers found that aseismic fault movement starts several years before an earthquake occurs. If this appears to be characteristic of all major earthquakes in this region this could in the future help the early detection of earthquakes.

Session: GD09/G13 Modelling and Monitoring the Deformation and State of Stress of the Lithosphere | >>programme

Annemarie Muntendam-Bos (Utrecht University) This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Götz Bokelmann (University of Montpellier) This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Anke Friedrich (University of Hannover) This e-mail address is being protected from spam bots, you need JavaScript enabled to view it