The Potential of Using Strain Data in Earthquake Early Warning: Near-Source Characteristics

Date: 4/25/2019

Time: 05:00 PM

Room: Puget Sound

The success of earthquake early warning (EEW) depends on the system response time and the accuracy of ground motion estimates. While highly dependent on instrumental coverage density and algorithm performance, such factors need to be continuously enhanced to improve the usefulness of EEW systems. In this work, we investigate the use of strainmeter data to complement seismometer data in EEW, noting that strainmeters have a linear response at all frequencies and have been found to record seismic waves with a high signal-to-noise ratio. We focus on data from Plate Boundary Observatory borehole strainmeters (20 samples/s) deployed in critical locations along the Pacific-North American plate boundary. We present a mathematical formulation relating earthquake moment magnitudes (Mw 3.5 - 5.7) observed near-field strains (< 60 km hypocentral distance) recorded during early-time evolution of the strain seismogram. Additionally, we discuss the performance of this formulation in providing real-time magnitude updates that can be used to forecast ground motion in vulnerable areas. Furthermore, we explore the spectral characteristics of strain data, and discuss the challenges of strain data processing in general and studying near-field effects in particular.

Presenting Author: Noha S. Farghal

Authors