Testing the Reproducibility of Remote Surface Rupture Maps of the 2019 Ridgecrest Earthquakes

Elaine K. Young, Michael E. Oskin, & Alba M. Rodriguez Padilla

Published August 15, 2020, SCEC Contribution #10687, 2020 SCEC Annual Meeting Poster #019

We present an independent effort to use post-earthquake lidar data and other imagery to remotely map surface ruptures and measure offsets produced by the 2019 Ridgecrest Earthquake sequence. The 4 July MW 6.4 and 5 July MW 7.1 earthquakes produced surface rupture zones approximately 20 km and 50 km in length, respectively, that span up to four kilometers in width, with numerous surficial fractures occurring more than 10 km from the main rupture. The purpose of this study is to develop an objective, uniform map product from which we test 1) the reproducibility of remote surface-rupture mapping and slip measurements between individual remote mappers and 2) the accuracy of remote compared to field-derived surface-rupture mapping and slip measurements. The first phase of this project is remote mapping of the surface rupture by three independent mappers with various backgrounds in active tectonics. This mapping is done from the post-earthquake airborne lidar and imagery data, without input from post-earthquake field mapping. We also use other remote sensing data (e.g. InSAR) as a guide to locating ruptures, though the lidar is relied on for detailed mapping. Visual comparison of the three remote rupture maps show good agreement for features with steep slopes that are > 50 cm, or one pixel in the lidar data. For features that are less steep, or that have less topographic expression, interpretations of the data vary across mappers. We plan a second phase of remote analysis in which we will measure offsets and slip using exclusively remotely-sensed data, comparing remote measurements between mappers and comparing remote to field measurements.

Key Words
Ridgecrest, Earthquake, Surface Rupture, Lidar, Remote Mapping,

Citation
Young, E. K., Oskin, M. E., & Rodriguez Padilla, A. M. (2020, 08). Testing the Reproducibility of Remote Surface Rupture Maps of the 2019 Ridgecrest Earthquakes . Poster Presentation at 2020 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Geology