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Long-Period Strong Ground Motion Prediction for the Mw7.2 Earthquake Set by the Nankou-Sunhe Fault in Beijing

Description: 

The Nankou-Sunhe Fault is located in a potential source zone of high magnitude M7.5 in the geoseismic parameter zoning map of China, although no major earthquakes have occurred in history. Taking into account the statistical relationships between macroscopic dimensions of faults and source parameters by scholars from China, the United States, and the former Soviet Union, 35 models with different rupture directions of single and double Asperity were set, and a three-dimensional crustal and upper mantle structure model of the Beijing basin and its surrounding area was constructed based on the available geological and geophysical sounding results, we performed predictions and statistical analysis, and the results showed that (1) under the strong ground motion effect of unilateral rupture mode from northwest to southeast, the Beijing basin has a large amplification effect, and strong ground motion will be generated in Changping, Beijing Center, Shunyi and Tongxian. The intensity of these areas can reach IX degrees and above, and the engineering structures, especially the high-rise buildings, will suffer serious seismic risks. The intensity VIII degree area includes the southeast suburbs of Beijing, Sanhe, Dafang, Baodi County and other areas, and the impact range is very large, the seismic mitigation situation in this area will be serious. (2) When the earthquake source ruptures in the reverse direction, the influence of the mountain topography and underground structure in the northwest has a significant blocking effect, resulting in the seismic wave spreading instead in an intensity map with the main axis in the northeast-southwest direction, and the intensity curve is nearly perpendicular to the fault direction, and the extreme zone only reaches intensity VIII with a small distribution area, which is low. This result is beyond the conventional understanding. This study provides an important reference for predicting the seismic intensity characteristics of destructive earthquakes in areas with few earthquake records.

Session: Understanding and Modeling the Uncertainties in Earthquake Ground Motions [Poster]

Type: Poster

Date: 4/20/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: XueLiang Chen

Student Presenter: No

Invited Presentation: 

Authors