基于孔隙介质BISQ模型的震电慢纵波传播特性

The Seismo-electric Slow Waves Propagation Characteristics Based on BISQ Poroelastic Model

目前的Pride震电理论不能准确地预测震电波的耦合特性和频散特性。为了更合理地反应震电耦合波波场的特征,本文基于包含Biot流动和喷射流动两种机制的BISQ模型,结合毛管模型中渗流场和电流场耦合理论,对Pride震电耦合理论进行了修正,进而对震电耦合波的传播特性进行了定量模拟。分析结果表明:特征喷射流长度对震电横波无影响;BISQ模型预测的震电快纵波传播速度比Pride理论预测的传播速度慢,BISQ模型的震电慢纵波衰减更显著,这表明BISQ模型比Pride震电理论更有效地预测了震电耦合波的衰减和频散。随着特征喷射流长度的增大,震电慢纵波的低频极限相速度减小,但不趋于零,这与Pride理论预测的不同。在低频区,BISQ模型预测的震电耦合波电场强度与固相速度之比的模值对特征喷射流长度非常敏感。

Currentl tics frequency y,the theory of Pride can not accurately predict the coupling characterisdispersion of seismo-electric waves. To reflect the coupling characteristics in the wave field reasonably, this paper based on the Blot flow and injection flow mechanisms of BISQ model, verifies the Pride seismo-electric coupling theory combining the flow field and current field in capillary model. Then the propagandation characteristics of coupling wave are numerically simulated. The simulation results showed that the length of injection flow has no effect on the R wave of seismo-electric wave. The velocity of fast P-wave predicted by BISQ model is larger than the theoretical predictions of Pride, and the dispersion phenomena of slow wave predicted by BISQ model is also significantly stronger. As R increases, low frequency phase velocity limit of the slow P-wave decreases, which is different from Pride theory. At last, the modulus predicted by the BISQ model increases with the reduction of the frequency, while in the low frequency region, the modulus is sensitive to R and decreases with its growing.