Crustal surface deformation monitoring is important in learning more about process of regional crustal movement. However, in eastern Hainan island, China, a paucity of near-field geodetic observations making the in situ crustal movement poorly understood. In this study, on the basis of ALOS PALSAR images, deformation field during 2007 and 2011 of the eastern Hainan island region was captured by stacking-InSAR approach. The results show a trough deformation pattern, running along the small to moderate size earthquakes belt, with an average peak-to-trough range change rate about 5 mm/yr. A magma-fed dike was responsible for the observed surface deformation pattern. The model dike is approximately 56 km long, 8 km wide, dipping 70° to the west, centered 25 km beneath eastern Hainan island, and strikes nearly N–S, parallel to the elongate pattern of seismicity in the area. We infer that the regional stress field favors the formation of dike beneath eastern Hainan island, and as a result the intruding magma accumulated in an elongate, dike-like storage zone. The zone dilated progressively over time, accompanied by sporadic earthquakes and subtle surface deformation. This study shows a typical example of dike-intrusion-derived large-scale deformation and is helpful for future local seismic hazard assessments.[阅读全文]