The rapid magnitude determination of an earthquake is at present one of the most important keys to issue tsunami warnings effectively. The goal of this study is to provide an effective magnitude determination method for tsunami warning purpose by analyzing local records of the Central America region. All the data was retrieved from IRIS database from 1995 to 2017 in an epicentral distance range up to 10 degrees and in the magnitudes range between M_w 6 to 7.7. The magnitude range is set so that events which could have tsunami-generating potentials are included. The method utilizes peak displacement amplitudes of different cut-off frequency. The displacement records are transformed from the original record with a deconvolution filter to correct the instrumental response and high-pass filters. The magnitude is obtained with a simple empirical formula from the peak amplitude. The results obtained using this method scatter considerably from the moment magnitude value of earthquakes in study. This behavior could be caused by the values of coefficients in the formula for amplitude and hypocentral distance. Better coefficients were estimated for the events in this region.
Keywords: Tsunami warning, rapid magnitude determination, local seismic records