Dapeng Zhao 교수

Abstract We present high‐resolution 3‐D images of P wave velocity ( Vp ), azimuthal anisotropy (AAN), and radial anisotropy (RAN) down to 900‐km depth beneath Alaska obtained by inverting a large number of high‐quality arrival time data from local earthquakes and teleseismic events simultaneously. Our results show that the high‐ Vp Pacific slab has subducted down to 450‐ to 500‐km depths. A prominent slab gap is revealed at depths of 65–120 km near the Wrangell volcanic field, which is likely a

Abstract The first tomographic images of P wave azimuthal and radial anisotropies in the crust and upper mantle beneath the Alps are determined by joint inversions of arrival time data of local earthquakes and teleseismic events. Our results show the south dipping European plate with a high‐velocity (high‐V) anomaly beneath the western central Alps and the north dipping Adriatic plate with a high‐V anomaly beneath the Eastern Alps, indicating that the subduction polarity changes along the strike

We determined P and S wave velocity tomography of the Japan subduction zone down to a depth of 700 km by conducting joint inversions of a large number of high-quality arrival-time data of local earthquakes and teleseismic events which are newly collected for this study. We also determined 2-D phase-velocity images of fundamental mode Rayleigh waves at periods of 20–150 s beneath Japan and the surrounding oceanic regions using amplitude and phase data of teleseismic Rayleigh waves. A detailed 3-D

SUMMARY Cenozoic basalts with ages ranging from 28.5 to < 0.1 Ma are widely distributed in the Indochina block, the South China Sea basin and the Leiqiong area in South China including the Leizhou Peninsula and the northern Hainan Island, which form the southeastern Asian basalt province (SABP). These Cenozoic basalts share common petrological and geochemical characteristics. However, the origin of the Cenozoic intraplate volcanism in the SABP is still a controversial issue. In this work,

The great 2011 Tohoku-oki earthquake [moment magnitude (<i>M</i>_w) 9.0)] is the best-documented megathrust earthquake in the world, but its causal mechanism is still in controversy because of the poor state of knowledge on the nature of the megathrust zone. We constrain the structure of the Tohoku forearc using seismic tomography, residual topography, and gravity data, which reveal a close relationship between structural heterogeneities in and around the megathrust zone and rupture pr

The ratio of the length of the second finger to the fourth finger (2D:4D) is considered to be a putative proxy of prenatal exposure to testosterone, and has been increasingly used as a promising tool to evaluate the impact of prenatal androgenization in humans in such traits as physical performance. In this study, for the first time, we present 2D:4D data on adult participants of Han ethnicity. We consider the sexual dimorphism of 2D:4D and handgrip strength, and also report the relationship bet

Abstract We determine the first high‐resolution P and S wave attenuation ( Q ) tomography beneath the entire Japan Islands using a large number of high‐quality data collected from P and S wave velocity spectra of 4222 local shallow and intermediate‐depth earthquakes. The suboceanic earthquakes used in this study are relocated precisely using sP depth phases. Significant landward dipping high‐ Q zones are revealed clearly, which reflect the subducting Pacific slab beneath Hokkaido and Tohoku, and

Abstract We present 3‐D images of azimuthal anisotropy tomography of the crust and upper mantle of the Japan subduction zone, which are determined using a large number of high‐quality P and S wave arrival time data of local earthquakes and teleseismic events. A tomographic method for P wave velocity azimuthal anisotropy is modified and extended to invert S wave traveltimes for 3‐D S wave velocity azimuthal anisotropy. A joint inversion of the P and S wave data is conducted to constrain the 3‐D a

Abstract A detailed 3‐D model of P wave isotropic velocity and azimuthal anisotropy beneath SE Asia is obtained by jointly inverting local earthquake arrival times and teleseismic relative travel‐time residuals. Our results show that the high‐velocity (high‐V) subducting Australian slab has penetrated through the mantle transition zone (MTZ) and reached a depth of ∼1,200 km beneath Sumatra, whereas the high‐V slab has subducted toward the north and trapped within the MTZ beneath Java. The Hainan

How mantle materials flow and how intraslab fabrics align in subduction zones are two essential issues for clarifying material recycling between Earth's interior and surface. Investigating seismic anisotropy is one of a few viable technologies that can directly answer these questions. However, the detailed anisotropic structure of subduction zones is still unclear. Under a general hexagonal symmetry anisotropy assumption, we develop a tomographic method to determine a high-resolution three-dimen

Abstract We determine high‐resolution 3‐D tomographic images of P ‐wave isotropic velocity, radial anisotropy and azimuthal anisotropy beneath NE Asia down to 800 km depth. Our results show negative radial anisotropy (i.e., V horizontal &lt; V vertical ) in the asthenosphere of the big mantle wedge (BMW), which may reflect mineral alignment caused by vertical flow in the asthenosphere. Across the Tanlu fault zone (TLF), the western and eastern parts of the BMW exhibit high and low P ‐wave veloci

Abstract High‐resolution images of P ‐wave anisotropic tomography beneath the Eastern Mediterranean and Middle East are determined by inverting a large number of high‐quality P ‐wave arrival times. Our results clearly show along‐strike variations of subducting slabs in the Hellenic subduction zone. At least three high‐velocity anomalies are imaged beneath and behind the north Hellenides, which are associated with the subducting Hellenic slab at different stages, while in regions further south, a