Fault “Corrosion” by Fluid Injection: A Potential Cause of the November 2017 5.5 Korean Earthquake

Figure 2

Locations of earthquakes at Pohang in November 2017: foreshocks (red circles), the 15 November mainshock (red star), and aftershocks (black circles). Also shown are stations of the local seismograph network (blue triangles), the EGS site (green square), the thermal spa resort (; coordinates from [97]), and the borehole that yielded the in situ stress measurements discussed by [58] (). Focal mechanisms of the mainshock and five principal aftershocks, each labelled by , are drawn as standard lower (or back) focal hemisphere projections with compressional quadrants shaded. Modified from [7]. (a) map. (b) NW-SE cross-section along line illustrated in (a), showing schematically the two deep wells (solid green lines) and the interpreted plane of the Namsong Fault (dashed red line).

(a)

(b)