利用滚石估算月球Finsen撞击坑区域的古月震震级  

Estimation of history moonquakes in Finsen crater from boulder tracks

作　　者：陶莎 朱伯靖[3,4] 石耀霖[1,2] TAO Sha;ZHU BoJing;SHI YaoLin(College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;National Key Laboratory of Earth System Numerical Modeling and Application,College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 101408,China;Yunnan Observatories,Chinese Academy of Sciences,Kunming 650216,China;Center for Astronomical Mega-Science,Chinese Academy of Sciences,Beijing 100012,China)

机构地区：[1]中国科学院大学地球与行星科学学院,北京100049 [2]地球系统数值模拟与应用全国重点实验室,中国科学院大学地球与行星科学学院,北京101408 [3]中国科学院云南天文台,昆明650216 [4]中国科学院天文大科学研究中心,北京100012

出　　处：《地球物理学报》2025年第4期1221-1233,共13页Chinese Journal of Geophysics

基　　金：国家重点研发计划项目“基于动力学模型的中长期地震数值预测关键技术研究”(2023YFC3007300)课题3“数据模型双驱动地震中期数值预测”(2023YFC3007303)资助。

摘　　要：月球勘测轨道飞行器(Lunar Reconnaissance Orbiter,LRO)所拍摄的高分辨率照片显示月球Finsen撞击坑区域留有成规模的巨石从山坡上滚落的痕迹.现有研究认为浅源月震及陨石撞击都有可能是大量巨石滚落的原因.本文利用一个简单的二维模型来模拟巨石贴坡面滚动的过程,并给出不同情况下巨石贴坡面滚落所需的临界峰值加速度(Peak Ground Acceleration,PGA).计算结果显示:在月震波的作用下,一些巨石在一个或多个周期内的反复晃动下会发生贴坡面滚动,使得巨石发生贴坡面滚落所需的月震波临界PGA与巨石尺寸、巨石初始位置的坡度、月震波的卓越周期及水平竖直峰值加速度之比等参数有关;另一些巨石只能以跃起的形式发生滚动.通过LRO拍摄的高分辨率照片可以判断滚石的滚落方式,再结合滚石大小及其周围环境,就可以估计该区域可能发生的月震震级下限.本文给出了不同情况下巨石发生贴坡面滚动所需的月震震级下限,并以Finsen撞击坑区域的滚石为例,对该区域历史月震震级进行初步估计.High-resolution images taken by the Lunar Reconnaissance Orbiter(LRO)show the existence of a large number of boulder tracks within the Finsen crater.Current research suggests that shallow moonquakes and meteorite impacts are likely to be the cause of boulder falls.This paper simulates the process of boulder rolling down a slope based on a simplified model,and provides the critical Peak Ground Acceleration(PGA)required for boulder to start slope rolling under different conditions.The results show that some boulders will roll along the slope in one or more seismic wave periods.In this case,the critical PGA of the seismic wave required for the occurrence of the boulder slope rolling is related to the size of the boulder,the slope at the initial position,the dominant period of the seismic wave and the ratio of the horizontal and vertical peak ground acceleration.In other cases,the boulders may start jump rolling.Using high-resolution images taken by LRO to determine how the boulders fell,we can estimate the lower limit of the magnitude of moonquakes in this area.This paper provides the lower limit of the moonquake magnitude required for the boulders to start slope rolling under different conditions.A preliminary estimate of the lower limit of historical moonquake magnitude in the Finsen crater is made.

关 键 词：滚石 月震 峰值加速度 贴坡面滚动 跃起滚动 

分 类 号：P315[天文地球—地震学] P313[天文地球—固体地球物理学]