Present-day crustal deformation in the northeastern Tibetan Plateau and its correlation with spatiotemporal seismicity characteristics

Abstract

The Northeastern Tibetan Plateau (NTP) is a typical intraplate region with numerous faults and intense seismicity. This study aimed to enhance our understanding of the spatiotemporal evolution of the region’s seismicity. We first obtained the strain-rate characteristics by establishing a regional kinematic model using global navigation satellite system velocities from 1999 to 2007. Subsequently, we discussed the spatiotemporal evolution of seismicity by analyzing the correlation between the maximum shear-strain rate and earthquakes. Finally, we analyzed seismic hazards in the NTP, while determining regions with high earthquake risk. Our results indicated a complex diffuse deformation pattern owing to tectonic loading and strike- and thrust-fault activity. Higher maximum shear-strain rates primarily accumulated on large strike-slip faults. The NTP was categorized into two domains based on correlation analysis. In regions with the highest 59% maximum shear-strain rates, the correlation between the cumulative strain and seismicity-rate counts was higher than that in other regions. Seismicity in these regions evolved from localization to accumulation, while subsequently returning to the localization stage, and thus may have been influenced by earlier large earthquakes. Seismicity in the remaining 41% of the NTP, i.e., regions with relatively low strain rates, was categorized as being in the localization stage. Our findings revealed the spatiotemporal characteristics of seismicity in the NTP and may contribute to future seismic risk evaluations. Further research should conduct earthquake potential assessments, especially in low strain-state regions.