Atmospheric blocking anomalies as the synoptic precursors prior to the induced earthquakes: a new climatic conceptual model

Abstract

Blocking as an interruption of the climatological storm tracks means an extreme disturbance in the synoptic scale of atmospheric circulation. In this study, we aimed to describe the main role of atmospheric blocking on the earthquake prediction in the southern Iran. We gathered the subjective evidences of a block generation during April 5–9, 2013, which was clearly identified by anomalous data of geopotential height, air temperature, vertical velocity, rainfall rate and latent heat flux. Analysis of geopotential heights at the 500 and 300 hPa levels revealed that there was a dipole split-flow block with associated of a remarkable low-pressure anomaly (−76 m), which has established over southern Iran during April 5–9, 2013. This low pressure into three temporal sequences has influenced three epicenters of upcoming earthquake swarms in south parts of Iran during April and May 2013. Hence, we detected an atmospheric–lithospheric cycle as a climatic conceptual model that describes the chain of the blocking-associated rainfall, preceding rainfall-triggered seismic stress, cyclogenesis, thunderstorm and subsequent stress-induced seismicity. We claimed that the blocking-associated anomalies together with the persistence of low pressure could be the earthquake precursors within 3–33 days before the main seismic shocks in Iran.