David Sandwell, Xiaohua Xu, and their SDSU colleague Thomas Rockwell have continued to study the aftereffects of the 2019 Ridgecrest EQ doublet. Through the use of high gradient mapping, Sandwell, Xu and Rockwell were able to retrieve data on 100s of previously unmapped faults. While most faults appeared in the same direction of the prevailing techtonic stress, there were also many fractures that surprisingly slipped opposite. Sandwell, Xu, and Rockwell share the source of this "retrograde" slip with SCEC. Click here to read their findings.