Seismological detection of low‐velocity anomalies surrounding the mantle transition zone in Japan subduction zone

Spin transition zone in Earth's lower mantle.

Mineral properties in Earth's lower mantle are affected by iron electronic states, but representative pressures and temperatures have not yet been probed. Spin states of iron in lower-mantle ferropericlase have been measured up to 95 gigapascals and 2000 kelvin with x-ray emission in a laser-heated diamond cell. A gradual spin transition of iron occurs over a pressure-temperature range extendin...

Recurrence of postseismic coastal uplift, Kuril subduction zone, Japan

[1] Coastal stratigraphy of eastern Hokkaido indicates that decimeters of coastal uplift occurred repeatedly in the late Holocene. Employing radiocarbon dating and tephrochronology, we identify along a 100 km length of the Kuril subduction zone six uplift events since 2,800 years B.P. Uplift events occur at the same frequency as unusually high tsunamis. Each coastal uplift event, which occurs o...

Subduction zone rheology

Rheological flow laws can be obtained from studies using multi-anvil high-pressure systems with synchrotron-based piezometers and strain metrics. The high flux X-ray source provides minute-scale time resolution with accurate measurement of diffraction patterns and direct sample images. Measurements of length changes with an accuracy of one part in 104 are being developed and will provide a new ...

Subduction zone guided waves and the heterogeneity structure of the subducted plate: Intensity anomalies in northern Japan

[1] The subducting Pacific plate acts an efficient waveguide for high-frequency signals and often produces anomalously large intensity on the eastern seaboard of northern Japan during deep earthquakes. The waveform records in the region of high intensity show a low-frequency (f < 0.25 Hz) onset for both P and S waves, followed by large, highfrequency (f > 2 Hz) later arrivals with a long coda. ...

S velocity reversal in the mantle transition zone