The Coso volcanic field (CVF) is situated in a tectonically complex region in southern California, bounded by the Basin and Range in the east, the Sierra Nevada block in the west, the Owens Valley in the north, and the Garlock Fault in the south (Figure 1). The CVF is well-known for its compositionally bimodal Pleistocene magmatism, represented by the coexistence of high-silica rhyolite and basalts erupted at a constant rate during the past ∼0.5 Ma (e.g., Bacon, 1982;Manley & Bacon, 2000). The evolution of the CVF is closely related to a releasing bend between the Airport Lake Fault and the Owens Valley Fault, which was developed following the earlier extensional regime introduced by the westward propagating Basin and Range extension (e.g., Duffield et al., 1980;McQuarrie & Oskin, 2010;Monastero et al., 2005). The present-day transtensional deformation results in widely distributed crustal shearing and strike-slip faulting of the brittle upper crust, leading to intensive earthquake activities in this region (Monastero et al., 2005).Geochemical and thermobarometric studies indicate the existence of a long-lasting magma reservoir beneath the CVF in the upper to middle crust, which directly feeds the Pleistocene volcanic activities and supplies the

Summary We propose a frequency-domain finite-element (FDFE) method to simulate the 2-D SHTE mode seismoelectric and electroseismic waves. By neglecting the secondary weak wave field feedbacks, the SH and TE waves are solved, separately. In a finite plane region, propagations of both SH and TE waves can be described as the Helmholtz equation with boundary conditions, which is proved to be equivalent to the extremum of functional by conducting calculus of variation. The computation region is partitioned into structured rectangular elements with the bilinear interpolation. The proposed FDFE algorithm solves the wavefield in frequency domain and avoids adopting the quasi-static approximation. One advantage of the proposed algorithm is its ability to accurately simulate the seismoelectric and electroseismic responses generated from the free surface. We verify the proposed algorithm based on a layered model beneath a free surface by comparing the waveforms calculated using the FDFE algorithm with those calculated using analytically-based methods. The proposed algorithm is applied in feasibility studies of interface seismoelectric and electroseismic responses in exploring the hydrocarbon reservoir and monitoring the time-lapse pollutant within a sand channel.