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冻震是一类新型的自然灾害,其震感及震颤特征与一般构造型破坏性地震前兆现象相似,易造成人们的恐慌,也给工程设计人员带来担忧。目前国内外尚未提出相关数学模型描述冻震的形成机理、定量评估冻震震害水平,国内的相关报道甚至将冻震与冰震混淆。该文统计了已有的冻震记录,并基于能量假定估算了冻震可能达到的最大烈度及其地面峰值加速度(peak ground acceleration,PGA)。理论研究表明:冻震最大可能达到的修正Mercalli烈度(modified Mercalli intensity,MMI)为VI度,对应的地面峰值加速度低于典型构造型破坏性地震Elcentro-NS纪录的PGA的10%,冻震可能导致一般城镇钢筋混凝土建筑结构损伤开裂,但不会导致不可恢复性破坏。
Freezing shock is a new type of natural disasters. Its seismicity and tremor characteristics are similar to those of the general structural destructive earthquake precursors, which can cause people’s panic and bring concerns to engineering designers. At present, the related mathematical models have not yet been proposed to describe the formation mechanism of freezing shocks and quantitatively evaluate the level of earthquake damage caused by freezing shocks. The related domestic reports even confuse freeze-shock with ice-shaking. This paper collects the existing freezing records and estimates the maximum possible intensity of ground freezing and its peak ground acceleration (PGA) based on the energy assumption. Theoretical studies show that the maximum possible modified Mercalli intensity (MI) of frozen shocks is VI degree, and the corresponding peak ground acceleration is lower than 10% of the PGA recorded by the typical structural destructive earthquake Elcentro-NS. Resulting in the general urban reinforced concrete structures damage cracking, but does not lead to non-recoverable damage.