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…

Monte Carlo solutions to the radiative transfer equations are used to model translational and rotational motion seismogram envelopes in random elastic media with deterministic background structure assuming multiple anisotropic scattering. Observation and modelling of the three additional components of rotational motions can provide independent information about wave propagation in the Earth’s…

Since centroid moment tensor (CMT) solution is not enough to describe the mechanism variations of large earthquakes, multiple CMTs were investigated in recent years by inverting seismic waveforms to retrieve the mechanism complexities. However, a problem in these wave for minversions is the trade-off between spatial mechanism variation and temporal rupture process, which may lead to ambiguous r…

Detection of low magnitude event is critical and challenging in seismology. We develop a new method, named the match and locate (M&L) method, for small event detection. The M&L method employs some template events and detects small events through stacking cross correlograms between wave forms of the template events and potential small event signals in the continuous waveforms over multiple stati…

Reaching sub-salt hydrocarbon targets in the deeper part of the Gulf of Mexico requires drilling through a salt canopy. The suture zones in the salt canopy are potential drilling hazards due to anomalous pressure behaviour of entrapped sediments. The P´olyavector field of coalescing salt sheets inside the canopy is used to explain suture formation and distinguish between upright and incl…

The seismic structure of Earth’s inner core is highly complex, displaying strong anisotropy and further regional variations. However, few seismic waves are sensitive to the inner core and fundamental questions regarding the origin of the observed seismic features remain un answered. Thus, new techniques to observe different types of inner core waves are imperative to improve data coverage. He…

Geomagnetic jerks are sudden changes of trend in the geomagnetic secular variation. The Earth’s mantle behaves as a filter for the jerks, causing a delayed and a smoothed signal at theEarth’s surface. Backus’ mantle filter theory relieson approximating the impulseresponse function (IRF) of the mantle by a Gaussian. The advantage of this theory is the linear relation between je…

3-D electromagnetic (EM) studies of the Earth have advanced significantly over the past decade. Despite a certain success of the 3-D EM inversions of real data sets, the quantitative assessment of the recovered models is still a challenging problem. It is known that one can gain valuable information about model uncertainties from the analysis of Hessian matrix. However, even with modern c…

Fluids—essentially meteoric water—are present everywhere in the Earth’s crust, occasionally also with pressures higher than hydrostatic due to the tectonic strain imposed on impermeable undrained layers, to the impoundment of artificial lakes or to the forced injections required by oil and gas exploration and production. Experimental evidence suggests that such fluids fl…