Geopotential change by earthquakes ('GEQ')

The compressed file contains geopotential coefficients of solid Earth mass change by a number of earthquakes (See the table of the events below). All these events had gravity change signature in the GRACE-GRFO time series. This version includes 163 + 83 + 18 monthly series named as “GEQ_*” from April 2002 to December 2026: (1) 163 months from April 2002 to June 2017, corresponding to the GRACE L2 series (2) 83 months from June 2018 to June 2025 for the GRACE-FO L2 (currently avaiable on Sept. 5 2025). (3) 18 months from July 2025 to December, extended to December 2026 The time tag used in the file name is in sync with the latest CSR L2 solution time tag. The geopotential change is evaluated at the average epoch of start and end time of each month. The same normalization as the project L2 solutions was used. The file named “GEQ_mean” is the mean geopotential averaged from these monthly files between April 2002 and June 2017 (GRACE period). This time period is consistent with the reference field “GOCO06s”. For example, if one takes the difference between “GEQ_2024153-2024182” and “GEQ_mean”, this result is comparable to L2 solution in June 2024 with respect to GOCO06s. The earthquakes considered in the GEQ series include: 2004 Mw8.1 Mcquarie 2004 Mw9.2 Sumatra 2005 Mw8.6 Nias 2006/7 Mw8.3 Kuril 2007 Mw8.5 Bengkulu 2009 Mw8.1 Samoa 2010 Mw8.8 Maule 2011 Mw9.1 Tohoku 2012 Mw8.6 Indian Ocn 2013 Mw8.3 Okhotsk 2016/17 Mw8.1 Papua NG 2019 Mw7.9 Peru The geopotential change is computed based on physics-based model (elastic and viscoelastic normal modes) [Han et al., 2013; Han et al., 2014]. Han, S.-C., R. Riva, J. Sauber, and E. Okal (2013), Source parameter inversion for recent great earthquakes from a decade-long observation of global gravity fields, J. Geophys. Res. Solid Earth, 118, 1240–1267, doi:10.1002/jgrb.50116. Han, S.-C., J. Sauber, and F. Pollitz (2014), Broadscale postseismic gravity changefollowing the 2011 Tohoku-Okiearthquake and implication for defor-mation by viscoelastic relaxation andafterslip, Geophys. Res. Lett., 41,5797–5805, doi:10.1002/2014GL060905. N.B. The comprehensive review paper on gravity modeling of all aforementioned events is in preparation. It is intended to update the GEQ series occasionally and expand by including more siginifcant events. Please send any question or comment to Shin-Chan Han ([e-mail]).