Local Magnitude Scaling Relations from P-waves in Turkey

Thursday, 18 December 2014
Mehmet Yilmazer, Kandilli Observatory, Istanbul, Turkey
We derive empirical magnitude scaling relationships between initial P-wave magnitudes (MLp) and the corresponding local magnitudes (ML). We used a dataset of approximately 6000 earthquakes, range in magnitude from 2.0 to 7.0, recorded in Turkey between 2010 and 2013. Only vertical components of waveform records, both velocity and acceleration, were used for MLp scaling assuming linear relationship between MLp and local magnitudes. Linear fitting results show that the residual-mean-square is around 0.02 for full set of data. The average error in calculated MLp magnitudes is 0.20 magnitude units for events with magnitudes smaller than 3.5 (M<3.5), 0.25 magnitude units for events with magnitudes from 3.5 to 5.0 (3.5<=M<5.0) and 0.30 magnitude units for events with magnitudes greater than 5.0 (M>=5.0). Proposed MLp scaling relationship could be used to estimate reasonable earthquake magnitude rapidly without waiting for S-wave arrivals.