FinITE Fault RUptures

Finite Fault Rupture Detector (FinDer)

 

To provide rapid estimates of fault rupture extent during large earthquakes, we have developed the Finite Fault Rupture Detector algorithm, FinDer. FinDer uses image recognition techniques to detect automatically surface-projected fault ruptures in real-time (assuming a line source) by estimating their current centroid position, length L, and strike θ. The approach is based on a rapid high-frequency near/far-source classification of ground motion amplitudes in a dense seismic network (station spacing < 50 km), and comparison with a set of pre-calculated templates using Matching by Correlation. To increase computational efficiency, we perform the correlation in the wavenumber domain. FinDer keeps track of the current dimensions of a rupture in progress. Errors in L are typically on the same order as station spacing in the network. The continuously updated estimates of source geometries as provided by FinDer make predicted shaking intensities more accurate and thus more useful for earthquake early warning (EEW), ShakeMaps, and related products. The applicability of the algorithm is demonstrated for several recorded and simulated earthquakes with different focal mechanisms, including the 2009 Mw 6.3 LAquila (Italy), the 1999 Mw 7.6 ChiChi (Taiwan), and the Mw 7.8 ShakeOut scenario earthquake on the southern San Andreas Fault (California). We are currently extending the approach to 3D to allow application to large subduction-zone earthquakes.

 

References:

Bӧse, M., T.H. Heaton, and E. Hauksson, 2012: Real-time Finite Fault Rupture Detector (FinDer) for Large Earthquakes, Geophys. J. Int., 191(2), pp. 803-812, doi: 10.1111/j.1365-246X.2012.05657.x link

 

 

Last up-date:

12/13/2012

Maren Bӧse, Phd

Senior ReseaRch Fellow