We determined focal mechanisms of earthquakes that occurred in between 2014 and 2017 in the Guayaquil area (costal side of Ecuador) using P wave polarity. We used waveform data recorded at local stations of the National Seismic Network of Geophysical Institute to prepare dataset. We compared the focal mechanism solutions of the three events obtained in this study to the moment tensor solutions from other methods; they are rather similar. To explicitly investigate the effects of depth errors and velocity structures, we determined focal mechanisms for different sets of focal depths and velocity models. The results indicate that the difference between the focal mechanisms and the moment tensor solutions are partly due to these effects. Among the twenty one events that we analyzed we obtained relatively high quality solutions for seven events whose magnitudes are in the range between 4.0 and 5.8. These results suggest that it is possible to increase focal mechanism solutions by analyses of local data.
Keywords: Guayaquil – Ecuador, Focal Mechanisms, Local data