The Stress Triggering of the 2025 Dingri,Xizang,China MW 6.8 Earthquake by the 2015 Nepal MW 7.8 and MW 7.2 Earthquakes
Jin Zhitong
Zhou Mingyue
Huang Jichao
Wan Yongge
Abstract：The stress triggering of the 2015 Nepal MW7.8 and MW7.2 earthquakes on the 2025 Dingri MW6.8 earthquake and its seismogenic fault are analyzed and discussed in this study,based on the rupture models of the two Nepal earthquakes and a layered viscoelastic crustal velocity model.The results show follows:(1)The 2015 Nepal MW7.8 earthquake caused a Coulomb stress change of 0.003 9 MPa at the source location of the Dingri earthquake,which was significantly greater than the stress modulation caused by solid tides,indicating that it played a promoting role in the occurrence of the Dingri earthquake.The combined Coulomb stress changes from the 2015 Nepal MW7.8 and MW7.2 earthquakes at the source location of the Dingri earthquake amounted to 0.010 4 MPa,exceeding the seismic stress triggering threshold of 0.01 MPa,suggesting that the joint effect of the two earthquakes significantly promoted the occurrence of the Dingri earthquake.(2)During the Dingri earthquake,both the MW7+earthquakes caused positive Coulomb stress changes on its seismogenic fault plane,with an average Coulomb stress change of 8 837 Pa.Especially at the source of the Dingri earthquake,the Coulomb stress change exceeded the stress triggering threshold of 0.01 MPa,indicating that the two earthquakes effectively increased the stress level on the seismogenic fault plane of the Dingri earthquake,having a significant triggering effect on the source location of the Dingri earthquake.(3)Considering the two MW7+earthquakes in 2015,along with the two MS5.9 earthquakes in Dingri in 2015 and 2020,it was found that the 2015 Dingri earthquake had a suppressing effect on the Dingri earthquake,while the 2020 MS5.9 Dingri earthquake had a promoting effect.The combined Coulomb stress changes from these four earthquakes amounted to 0.01 MPa,which triggered the Dingri earthquake.The results of this study provide basic data and information for understanding the seismic hazard analysis of the fault where the Dingri earthquake occurred,with significance for the seismic activity at the boundary of the Indian Plate and the Eurasian Plate,as well as the tectonic evolution of the Tibetan Plateau.
Keywords：NepalDingriXizangChinaearthquakerupture modelCoulomb stress changestress triggeringtectonics
Publication Date：2025-05-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：12( 1782-1793 )