SEISMIC MOMENTS AND VOLUME CHANGES
SEISMIC MOMENTS AND VOLUME CHANGES
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DOI：
10.1029/jb081i008p01487
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发表时间：
1976-01-01
影响因子：
--
通讯作者：
MCGARR, A
中科院分区：
文献类型：
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作者：
MCGARR, A
对于许多实际感兴趣的情况，由与体积变化相关的地面变形引起的地震活动性ΔV与体积变化的关系为ΣM0=Kμ∣ΔV∣，其中ΣM0is是地震群的地震矩之和，μ是刚度模量，kis是接近1的因子。这种关系的一个必要条件是，体积的变化只能由地震破坏来适应。地震矩与体积变化之间的关系被用来分析由地面变形引起的地震序列，这种变形最容易被描述为体积变化。首先，在南非的East Rand专有金矿，发现矿山震动的总地震矩与从开采岩石体积推断的总地震矩非常吻合。其次，将丹佛地震的年地震矩总和与洛基山兵工厂井注入流体的体积估计的年总地震矩进行比较。在流体年注入率较高的1962年至1965年期间，计算力矩与观测力矩吻合良好。这些年来，几乎所有的丹佛地震都与深部注入流体的调节相对应。1966年2月之后发生的地震（当时流体注入被停止）与落基山武库井之间的关系尚不清楚。最后，发现1966年3月至9月发生在日本松城附近的地震的总地震矩与由水平和垂直地面运动测量确定的震源区扩展计算的地震矩符合得很好。计算了此处考虑的体积变化的能量变化，并与地震波辐射的总能量进行了比较。地震能量占总能量变化的0.2% ~ 3%。
For many situations of practical interest, the seismicity that results from ground deformation associated with a change in volume, ΔV, is related to the volume change by ΣM0=Kμ∣ΔV∣, where ΣM0is the sum of the seismic moments of the earthquake population, μ is the modulus of rigidity, andKis a factor close to 1. A necessary condition for this relationship is that the change in volume is accommodated only by seismic failure. The relationship between seismic moment and volume change was used to analyze earthquake sequences resulting from ground deformation that could most easily be described as volume changes. First, in the East Rand Proprietary Gold Mine, South Africa, total seismic moments of mine tremors were found to be in good agreement with total moments inferred from the volume of rock mined. Second, annual sums of seismic moments for the Denver earthquakes were compared with yearly total moments estimated from the volume of fluid injected at the Rocky Mountain arsenal well. There was good agreement between calculated and observed moments from 1962 to 1965 when annual rates of fluid injection were high. Nearly all of the Denver earthquakes in these years correspond to the accommodation of injected fluid at depth. The association between earthquakes that occurred after February 1966, when the fluid injection was stopped, and the Rocky Mountain arsenal well is not clear. Finally, the total seismic moment for earthquakes near Matsushiro, Japan, that occurred from March to September 1966 was found to be in good agreement with the moment calculated from the expansion of the seismic source region determined from measurements of horizontal and vertical ground movement. Energy changes were calculated for the volumetric changes considered here and compared with the total energy radiated in the seismic waves. The seismic energies ranged from 0.2% to 3% of the total energy changes.