Seismic Intensity Field Surveys and a Comparison with Strong Motion Data for the 2018 M8.2 Chiapas and the 2016 M7.8 Ecuador Events

Session: Earthquake Source Parameters: Theory, Observations and Interpretations [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

We conducted regional seismic intensity field surveys following the M7.8 Muisne, Ecuador earthquake of April 16, 2016 and the M8.2 Tehuantepec, Mexico earthquake of September 7, 2017. In both studies, we observed numerous structures that had totally or partially collapsed due to a combination of poor construction, unconsolidated soil and other effects of the high frequency (5-10 Hz) ground shaking experienced during these earthquakes. We determined empirical relationship between instrumental peak ground motions and observed intensities for both of these events. The Modified Mercalli Intensities (MMIs) for the Ecuador event reached a maximum value of VII and the Peak Ground Velocities (PGVs) and Peak Ground Accelerations (PGAs) reached a maximum value of 82 cm/s and 1,410 cm/sec². In our study of the Tehuantepec earthquake, we observed a Modified Mercalli Intensity (MMI) value of VII, lower than the predicted value of IX. We compare the MMI intensities and high frequency ground shaking between these events. These results contribute to a growing database of strong motion observations for large subduction zone and intraplate earthquakes.

Presenting Author: Ellen M. Smith

Authors