Figure 1
From: Imaging evolution of Cascadia slow-slip event using high-rate GPS
Tectonic setting of Cascadia subduction zone and comparison of cumulative GPS displacements derived from the 30-min and the daily data. (a) The solid bold black line indicates the trench of the two converging plates as labelled. The broken lines indicate slab surface depth contours (10 km interval from 10-km depth)37. The solid brown line outlines the interseismic locking depth38, defined as a contour of locking ratio = 0.7. The small dots color-coded with time indicate tremor epicentres detected by PNSN (https://pnsn.org/tremor; Downloaded in 25 June 2021). (b) Cumulative GPS displacements at selected sites using the 30-min (red) and the daily (blue) data. The cumulative displacements for the 30-min data are obtained as the difference of the initial and the final positions, which are defined as the average positions during the first (15–17 March 2017) and the last 3 days (10–12 April 2017), respectively. Outliers deviating from the average by more than 3 times of the standard deviation were removed when taking the averages. The cumulative displacements for the daily data are simply obtained by the difference of the positions at the first (15 March 2021) and the last days (12 April 2021). Prior to the displacement computation, each time series were corrected for whole network translation estimated in each slip inversion. The same figure but showing all the sites in the entire area is presented in Fig. S4.
