2023年8月6日山东平原发生MS 5.5地震，中国地震台网中心获得丰富的测震和强震台站三分量波形数据。使用2° —10°震中距范围内80个台站的宽频带垂直向速度记录，测量该地震的宽频带面波震级；使用震中距200 km范围内1 278个强震仪和简易烈度计三分量记录，计算近场强震动加速度反应谱值。结果表明，宽频带面波震级MS(BB)平均值为5.5，震中西南侧台站测定震级相对偏小，偏大台站多分布在东北侧。近场强震动加速度反应谱呈NE—SW走向的条带状分布特征，沿断层破裂方向衰减慢，垂直断层方向衰减快。宽频带面波震级和加速度反应谱的空间分布特征支持本次地震以东北向单侧破裂为主，对照震中区地震断层资料，本次地震可能属于高唐和陵县—阳信隐伏断裂体系。
On August 6, 2023, a MS 5.5 earthquake occurred in Pingyuan County, Shandong Province. The China Earthquake Networks Center obtained abundant three-component waveform data from seismic and strong ground motion stations. In this paper, we used broadband vertical component velocity records from 80 stations within a 2°- 10° epicentral distance to measure the surface-wave magnitude of this event. Using three component recordings of 1 278 strong ground motion instruments and simple intensity meters within 200 km, we calculate the acceleration response spectra. The results show that the surface-wave magnitude MS(BB) averaged 5.5, and those stations with relatively small magnitudes are mostly distributed on the southwest side of the epicenter, while those with larger magnitudes are in the northeast. The acceleration response spectra within 200 km in the near-field show an NE-SW trend with a strip-shaped distribution characteristic, and along the fault rupture direction, the attenuation is slow while fast along the vertical fault direction. The spatial distribution of broadband surface-wave magnitude and acceleration response spectra support the unilateral rupture, mainly in the NE direction. According to the seismic fault data in the epicenter area, the earthquake may belong to the Gaotang and Lingxian-Yangxin hidden fault system.
2023,44（6）: 13-19 收稿日期：2023-9-21
DOI：10.3969/j.issn.1003-3246.2023.06.002
基金项目：地震科技星火计划（项目编号：XH23050YB）；国家自然科学基金（项目编号：42304072）
作者简介：韩光洁（1993—），工程师，主要从事地震监测和震源破裂过程方面的研究。E-mail：hangj@seis.ac.cn
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