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The Healing Process and Healing Time Estimate of the Longmenshan Fault After the Wenchuan Earthquake

Description: 

The recovery process of fault locking degree is an important reflection of fault healing process, so the fault healing process can be effectively identified according to the evolution characteristics of fault locking degree determined by inversion. According to the inversion results of multi-stage GPS horizontal velocity field data, the time of complete healing can be basically determined for the healed section. For the ruptured sections still in the healing process, the healing time can be estimated by logarithmic fitting (Pei et al., 2019): Firstly, according to the inversion results of multi-stage data, the dynamic locking degree at the same node were extracted, and the value were fitted with a logarithmic function. After the optimal fitting, the required time of complete healing was estimated.

In this paper, we study the evolution process of the locking degree in the middle section of Longmenshan fault after the Wenchuan earthquake. The results show that: along the fault dip direction, multiple columns of nodes show rapid recovery of strong locking from shallow to deep, that is, the fault plane quickly recovers healing state from the surface to deep. Along the strike direction, multiple rows of nodes show rapid recovery of strong locking from southwest to northeast of fault, that is, the fault plane quickly recovers healing state from the rupture termination position to the source direction. At present, the process of fault healing is just the opposite of the coseismic rupture, and the healing area has reached the source, and the healing rate is very fast. Combined with the healing process of the northeast section, it can be inferred that the healing of the whole Longmenshan fault plane will take about 10 years more. After the fault healing, it means that the fault begins to accumulate energy rapidly. The research results of the Wenchuan earthquake show that its recurrence cycle is about 2500-5000 years (Zhang et al., 2008; Zhao et al., 2012), so it will take long time to accumulate enough energy to form an asperity of M8 earthquake.

This work was supported by Science for earthquake resilience (XH23047A).

Session: Above the Seismogenic Zone: Fault Damage and Healing in the Shallow Crust [Poster]

Type: Poster

Date: 4/19/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Jing Zhao

Student Presenter: No

Invited Presentation: 

Authors