In this directory, there are preliminary GPS displacement tables and figures for March 11, 2011 M9 Japanese earthquake Provided by the ARIA team at JPL and Caltech. In your use of these time series, please use the following accreditation: "Preliminary GPS time series provided by the ARIA team at JPL and Caltech. All original GEONET RINEX data provided to Caltech by the Geospatial Information Authority (GSI) of Japan. Processing Strategy ------------------- These displacements are based on kinematic precise point positioning solutions using JPL's GIPSY-OASIS software, including single station bias fixing method, and JPL's Rapid orbit and clock products. In the time series directory, there are the kinematic solution files used to estimate the displacements. Offset Calculation ------------------ The co- and postseismic offsets are a simple difference between the position estimates at two different solution epochs (epochs used given in table header). We will revise these estimates in the future with estimates calculated using time series analysis. Coseismic Version 0.2: 30 minute solutions ------------------------------------------ The version 0.2 set of coseismic displacements are estimated from our 30 minute interval kinematic solutions. The coseismic displacements are the difference between the solution at 05:00 UTC and 06:30 UTC (earthquake occurred at 05:46 UTC). Since there were large aftershocks in the first hour after the earthquake, some of the displacements due to these aftershocks may be included in these "coseismic" offsets. Coseismic Version 0.3: 5 minute solutions ------------------------------------------ The version 0.3 set of coseismic displacements are estimated from our 5 minute interval kinematic solutions. The coseismic displacements are the difference between the solution at 5:40 UTC and 5:55 UTC (earthquake occurred at 05:46 UTC). These displacements therefore include fewer aftershocks and less displacement due to aseismic postseismic slip that V0.2. However, the position estimates for the 5 minute solutions are noisier than the 30 minute solutions, particularly for the vertical component. Note the vertical coseismic displacement figure for V0.3 appears noisier than same figure for V0.2. Why do coseismic horizontal vectors in V0.1 (in 'old' directory) look different? -------------------------------------------------------------------------------- The V0.1 vectors have noticeably different azimuths than the V0.2 and V0.3 vectors. This is most likely due to the initial pre-seismic position estimates that were used for V0.1, which we discovered were not as accurate as position estimates closer to the time of the earthquake. For questions, contact ARIA team at aria@jpl.nasa.gov or aria@caltech.edu