Towards faster & more accurate earthquake locations: New real-time approaches for Earthquake Early Warning

To maximize the warning time in case of a destructive earthquake, the location has to be found with as few stations as possible. But due to this, today's standard approaches lead to often misplaced hypocenter locations, being strongly affected by inaccuracies in the velocity model and outliers in the data (i.e. mis-picked phase arrivals by the automated picking algorithms), which consequently leads to false and missed alarms.

The incentive to constrain earthquake locations accurately as early as possible has motivated the development of several new constraint-based location schemes, which provide robust locations by accounting for uncertainties in the velocity model and phase picking, further unlocking new information constraining the location.

Among these is the concept of Not-Yet-Arrived-Data (NYAD), which uses both the arrivals and non-arrivals of P- and S-phases to constrain the hypocenter to a shrinking region surrounding the first triggered station. This provides minimum hypocentral distance estimates prior to the S-phase arrival and consecutively real-time minimum magnitude estimates, from the first detection on. A new network of small aperture arrays set up in the Dead-Sea basin adds robust azimuthal constraints and an unprecedented quality of real-time phase classification that allows to reduce the minimum number of triggered stations to only two. Thus, it drastically reduces the time required for hypocenter estimates and warning, crucial for Israel having population centers in the vicinity of the active regions

 

Andreas Eisermann, Hillel Wust-Bloch, and Alon Ziv Department of Geosciences, Tel Aviv University, Israel eisermann@tau.ac.il

 

 


תאריך 21/05/2017 10:30 12:00
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