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• The rupture process of the 2014 M w 6.2 Ludian earthquake was constrained by teleseismic data and more strong-motion data. • The Ludian earthquake ruptured two conjugate faults with strike angles of 77° and 160°, respectively. • The rupture simultaneously took place on two conjugate faults and lasted approximately 10 s. • The shallow dominating slip patch is the main reason for the enormous disaster from the earthquake source perspective. The M w 6.2 Ludian earthquake, struck Yunnan, China on August 3rd, 2014, leading to a complex aftershock distribution and enormous disaster. The Ludian earthquake is well recorded by the China Earthquake Network. The rupture process of the Ludian earthquake is constrained by the more local strong motion data including the LLT station with epicentral distance of ∼2 km and teleseismic body waves and surface waves in this study. The local strong motion data constrained the epicenter's location and rupture process better. Waveform fit of key local strong-motion stations supported that the Ludian earthquake ruptured two conjugate faults with strike angles of 77° and 160°, respectively. The rupture simultaneously took place on two conjugate faults and lasted approximately 10 s. The peak slip, rise time, and average slip rate are 0.63 m, 0.69 s, and 2.12 m/s, respectively. The result shows that the main rupture zone was on the fault with a strike of 160°. The depth of the major slip patch was 0–4 km with a centroid depth of 2 km. It indicates that the shallow slip is the main reason for the enormous disaster from the earthquake source perspective. [ABSTRACT FROM AUTHOR]

Geological studies show that the southern part of Ailaoshan-Red River shear zone (ALSRRSZ) has experienced complex metallogenic processes and multi-stage non-uniform uplifting, called oblique uplifting since the Cenozoic. To detect the deep structure and geodynamic background beneath Daping, Chang'an and other gold and polymetallic deposits in this area, we carried out a high-density short-period seismic array survey in southern Yunnan province. The array used is approximately 240 km long with an interval of 500 m between two adjacent stations. Based on the data collected by the array, we used H-κ stacking and common conversion point (CCP) methods of receiver functions to reveal the fine crustal structure beneath this array, which was located from Lvchun (western end) to the east and ended in Maguan. The three main conclusions are as follows. (1) The average crustal thickness is approximately 37 km and the Vp/Vs ratio is 1.75. However, the thickness and Vp/Vs ratio of the Ailao Mountain are rather greater or higher than those of the western Lanping-Simao Basin and eastern South-China block. These results may indicate that the crust is rich in ferromagnesian minerals or has a thermal fluid anomaly after orogenic movement. (2) There are two obvious inclined interfaces beneath the Ailao Mountain in the mid-upper crust, which suggests that strong deformation occurred there during the orogenic period. Some evidences, such as the weak converted-wave Pms phase from the Moho, low P-wave velocities of the upper mantle, high surface heat flow values, and generally developed hot springs, indicate that a strong crust-mantle interaction exists in the southern segments of the Ailaoshan-Red River shear zone. These interactions include a diapir of mantle-sourced magma (stronger in the east than that in the west), lateral collision from the Indian Plate, and the differential uplift caused by the strike-slip movement of the Red River Fault. All of above deep processes led to the Cenozoic oblique uplifting of Ailao Mountain. (3) By combining the location of the deposits on the surface, characteristics of the average crustal Vp/Vs ratio, hypocenters of the small earthquakes along the research profile, Moho shape, and horizontal variations of the Pms phase amplitudes, we speculate that the Ailaoshan Fault was the upgoing conduit for metallogenic magma and played a significant role in the Cenozoic development of the multiform metal deposits around the Ailao Mountain area. [ABSTRACT FROM AUTHOR]