Deep Earthquakes Can Generate Larger Co‐Seismic Displacements Than Shallow Events

Abstract We report the counter‐intuitive observation that a deep earthquake can generate larger co‐seismic displacements than a shallow event across a broad region (e.g., >4° from epicenter). This finding is based on a detailed comparative GNSS analysis of the co‐seismic displacement observations from two M W 8.3 events—the 2013 598.1 km‐deep Okhotsk event and the 2015 22.4 km‐deep Illapel event—revealing a maximum observed displacement difference of over 4 mm. Our modeling confirms the observation and demonstrates that this phenomenon primarily arises from the 3D displacement pattern generated by earthquakes, not from the effect of the Earth's curvature. These results are generalizable to other pairs of deep and shallow earthquakes, highlighting intermediate and deep earthquakes as substantial sources of surface deformation that should be systematically incorporated into our current framework of geodesy; moreover, geodetic data may offer new insights into the deep rupture process.