Electrical resistivity tomography (ERT) is a useful tool to detect and track water flow paths in the subsoil. However, measurements are strongly affected by sub surface heterogeneities such as fissures of different sizes and genesis (shrinking-swelling, macropores and deformation). In this work, we focus on surface fissures characterized by dimensions lower than the interelect…

In the context of elastic wave propagation, the non-periodic homogenization asymptotic method allows to find a smooth effective medium and equations that correspond to the wave propagation in a given complex elastic or acoustic medium down to a given minimum wavelength. By smoothing all discontinuities and fine scales of the original medium, the homogenization technique considerably…

We present high-resolution tomographic images in source areas of 26 large crustal earthquakes (M 6.0–7.2) which occurred in Northeast Japan (Tohoku) during the past 120 yr from 1894 to 2014. Prominent low-velocity (low-V) and high Poisson’s ratio (high-σ) anomalies are revealed in the crust and mantle wedge under the source areas. Beneath the volcanic front and backarc areas, the low-V…

Phase reversals are commonly observed during exploration seismic amplitude-versus-offset analysis, and usually modelled with the Zoeppritz equations. In practice, when multiple fluids are present we often deal with reflections from interfaces having a contrast in both elastic and anelastic properties. In this paper, we present a new phenomenological model for phase reversals in case…

This paper presents a method of in painting historical seismograms recorded by a pen and paper drum-typeseismograph. In these is mogram, some portions of the wave may belost or distorted owing to time marks or violent shaking. In this study, the seismic waveform is divided into several frames of equal length, and the lost or distorted portions are restored frame by frame. Because a seismogram c…

The segregation of melt from a linear viscous matrix is traditionally described by McKenzie’s compaction theory. This classical solution overlooks instabilities that arise when non-linear solid matrix behaviour is considered. Here we report a closed form 1-D solution obtained by extending McKenzie’s theory to non-linear matrix behaviours. The new solution provides periodic stress singularit…

We have developed a new geomagnetic data assimilation approach which uses the minimum variance’ estimate for the analysis state, and which models both the forecast (or model output) and observation errors using an empirical approach and parameter tuning. This system is used in a series of assimilation experiments using Gauss coefficients (hereafter referred to as observational data) fro…

Although often composing a non-negligible fraction of soil cation exchange capacity (CEC), the impact of soil organic matter (OM) on the electrical properties of soil has not been thoroughly investigated. In this research the impact of soil OM on the spectral induced polarization (SIP) signature of soil was investigated. Electrical and chemical measurements for two experiments using the same so…

Fishes are well known for their remarkable maneuverability and agility. Less visible is the continuous control of stability essential for the exploitation of the full range of aquatic resources. Perturbations to posture and trajectory arise from hydrostatic and hydrodynamic forces centered in a fish (intrinsic) and from the environment (extrinsic). Hydrostatic instabilities arise from vertical …

The flow of liquid metal inside the Earth’s core produces the geomagnetic field and its time variations. Understanding the variability of those deep currents is crucial to improve the forecast of geomagnetic field variations and may provide relevant information on the core dynamics. The main goal of this study is to extract and characterize the leading variability modes of c…