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 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…

There has been extensive work on seismic source localization, going as far back as Geiger’s 1912 paper, that is based on least-squares fitting of arrival times. The primary advantage of time-based methods over waveform-based methods (e.g. reverse-time migration and beam forming) is that simulated arrival times are considerably more reliable than simulated waveforms, especially in the context…

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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…

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Tahun Terbit

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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…

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