2017 UseIT: Probability Team

Chi Y. Loh, Olivia J. Dorencz, Aide Escanuela, Kevin F. Qualls, Kevin R. Milner, Thomas H. Jordan, Jozi K. Pearson, & Gabriela R. Noriega

Published August 3, 2017, SCEC Contribution #7404, 2017 SCEC Annual Meeting Poster #311

California is a high seismic-hazard area due to several dangerous faults that run through the state, primarily the San Andreas Fault (SAF). The dense population near the SAF in cities such as Los Angeles and San Francisco makes this hazard a significant risk. The 2017 Undergraduate Studies in Earthquake Information Technology (USEIT) Probabilities Team analyzed three different initial-event scenarios (M6.1 Parkfield, M7 Mojave, and M6 Bombay Beach) to create a short-term earthquake sequencing forecast for the southern California region, while looking at the probability of subsequent earthquakes of M > 7.0. To produce this forecast, three catalogs were generated from the Blue Waters supercomputer by the High Performance Computing Team, using Rate-State Earthquake Simulator (RSQSim). RSQSim can create long physics based catalogs, allowing us to study the statistics of large earthquakes. By changing the parameters for the rate (a), state (b), and cohesion coefficients, the HPC team was able to create three catalogs with different parameters, each approximately 500 thousand years long. The RSQSim catalogs were compared with each other and then compared to the Uniform California Earthquake Rupture Forecast version 3 (UCERF3) reports to determine the recurrence interval and conditional probabilities of large subsequent (M > 7) events, within a short period of time. We wrote Java code to analyze the catalogs looking at initial events at Parkfield, Mojave, and Bombay Beach. Then we searched through the catalog to estimate the conditional probabilities of a significant earthquake (M > 7) occurring in the next week, month, and year after the initial event scenarios. The collected data was then analyzed and visualized using Excel graphs.

Key Words
UseIT, Probability, Conditional Probability, Recurrence Interval, Magnitude Frequency, UCERF3, RSQSim, Earthquake Forecast, Aftershocks

Citation
Loh, C. Y., Dorencz, O. J., Escanuela, A., Qualls, K. F., Milner, K. R., Jordan, T. H., Pearson, J. K., & Noriega, G. R. (2017, 08). 2017 UseIT: Probability Team. Poster Presentation at 2017 SCEC Annual Meeting.

Related Projects & Working Groups
Communication, Education, and Outreach (CEO)