The early detection of the oil–water encroachment front is of prime interest during the water flooding of an oil reservoir to maximize the production of oil and to avoid the oil–water encroachment front to come too close to production wells. We propose a new 4-D inversion approach based on the Gauss–Newton approach to invert cross-well resistance data. The goal of this study is to image …

In order to study fine scale structure of the Earth’s deep interior, it is necessary to extract generally weak body wave phases from seismograms that interact with various discontinuities and heterogeneities. The recent deployment of large-scale dense arrays providing high-quality data, in combination with efficient seismic data processing techniques, may provide important and accurate observ…

In marine exploration seismology, surface-related multiples are usually treated as noise mainly because subsequent processing steps, such as migration velocity analysis and imaging, require multiple-free data. Failure to remove these wavefield components from the data may lead to erroneous estimates for migration velocity or result in strong coherent artefacts that interfere with the imaged ref…

Based on cross-correlations of ambient seismic noise computed using 61 ocean bottom seismometers (OBSs) within the Juan de Fuca (JdF) plate from the Cascadia Initiative experiment and 42 continental stations near the coast of the western United States, we investigate the locations of generation of the primary (11–20 s period) and secondary (5–10 s period) microseisms in the northern Pacific…

Based on 3-D finite difference method simulations of seismic wave propagation, we examined the processes by which the complex, scattered high-frequency (f > 1 Hz) seismic wavefield during crustal earthquakes is developed due to heterogeneous structure, which includes smallscale velocity inhomogeneity in subsurface structure and irregular surface topography on the surface, and compared with obse…

TheC-response is a conventional transfer function in global electromagnetic induction research and is traditionally determined from observations of magnetic variations in the vertical and horizontal components. Its interpretation relies on the assumption that the source of the variations is well approximated by a large-scale symmetric (magnetospheric) ring current, described by a single spheri…

Well established theoretical and numerical results of 2-D ruptures have been accepted for years to limit the speed of mode II cracks to be below the Rayleigh velocity or above the shear wave speed. However, recent work has numerically produced rupture speeds in this so-called ‘forbidden zone’, that is the region of rupture velocities between the Rayleigh wave speed and the shear wave speed…

We used ab initio molecular dynamics to calculate the elastic constants of MgSiO3, FeSiO3 and (Fe0.5Mg0.5)SiO3 perovskite under lower-most mantle conditions (136 GPa, 2000–4000 K). At 0K, Vp and Vs for FeSiO3 perovskite are 12 and 18 per cent lower, respectively than those for MgSiO3, in agreement with previous work. The difference in velocity, however, increases with temperature for high sp…

We determined the first high-resolution P- and S-wave attenuation (Qp and Qs) tomography of the crust and upper mantle under the entire Nankai subduction zone from the Nankai Trough to the Japan Sea using a large number of high-quality t∗ data measured from P- and S-wave spectra of local earthquakes. The suboceanic earthquakes used in this study were relocated precisely using sP depth ph…

On Earth, oceanic plates subduct beneath a variety of overriding plate (OP) styles, from relatively thin and negatively buoyant oceanic OPs to thick and neutrally/positively buoyant continental OPs. The inclusion of an OP in numerical models of self-consistent sub duction has been shown to reduce the rate that subducting slabs roll back relative to the equivalent single plate models. We use dyn…