FinDerS(+): Real-Time Earthquake Slip Profiles and Magnitudes Estimated from Backprojected Displacement with Consideration of Fault Source Maturity Gradient

The Finite-Fault Rupture Detector (FinDer) algorithm computes rapid line-source rupture models from high-frequency seismic acceleration amplitudes (PGA). In this paper, we propose two extensions to FinDer, called FinDerS and FinDerS+, which have the advantage of taking into account a geological property source fault, its structural maturity, as well relation earthquake slip distribution. These new algorithms calculate real-time profiles by backprojecting and/or geodetic displacement onto FinDer line-source. This backprojection is based on general empirical equation established in previous work that relates dynamic peak ground (PGD) at stations on-fault coseismic slip. While projects PGD current line-source, FinDerS+ allows grow beyond model extent predict future evolution. For an informed interpolation smoothing estimated values, both employ generic function has been shown relate along-strike gradient maturity ruptured distribution, length. Therefore, while derives magnitudes relatively uncertain length-magnitude relations, provide alternate better magnitude estimates using mean derived integration fault maturity. can incorporate strong-motion data. order recover instruments, double-integrate high-pass filter ( > 0.075 Hz) records. Together, three exploit full spectrum ground-motions, including high frequencies derive low determine static offsets along (FinDerS FinDerS+). We test for 2019 M W 7.1 Ridgecrest (California), 2016 7.0 Kumamoto (Japan), 2008 7.9 Wenchuan (China) earthquakes. Conclusively, low-frequency data do not speed-up calculations these events, but additional information distribution final length, alternative be useful check consistency across suite. systematically outperform previously PGD-based terms speed accuracy. resulting distributions improved ground-motion prediction given observed relationship between radiation