该课题组研究人员基于对阿曼蛇绿岩中的水合超镁铁质岩石中高温蛇纹石脉网的分析，限制了流体流过浅地幔楔的时间和速度。在扩散模型和时间积分流体通量的基础上，研究人员表明通道化流体流动是短暂的(2.1×10-1 到 1.1×101年)并具有高流体速度(2.7×10-3 到 4.9×10-2米每秒)，接近于现今俯冲带中地震事件的传播速度。研究结果表明，流体向上覆板块中的排放以幕式脉冲的形式出现，这可能会影响大逆冲地震的复发。
据介绍，俯冲带巨型逆冲断层上的孔隙流体压力，由于流体排入上覆板块而降低，从而影响俯冲带的地震活动。然而，人们对通过超俯冲带的流体流动的空间和时间尺度知之甚少。
附：英文原文
Title: Geological records of transient fluid drainage into the shallow mantle wedge
Author: Kazuki Yoshida, Ryosuke Oyanagi, Masao Kimura, Oliver Plümper, Mayuko Fukuyama, Atsushi Okamoto
Issue&Volume: 2023-04-05
Abstract: Pore fluid pressure on subduction zone megathrusts is lowered by fluid drainage into the overlying plate, affecting subduction zone seismicity. However, the spatial and temporal scales of fluid flow through suprasubduction zones are poorly understood. We constrain the duration and velocity of fluid flow through a shallow mantle wedge based on the analyses of vein networks consisting of high-temperature serpentine in hydrated ultramafic rocks from the Oman ophiolite. On the basis of a diffusion model and the time-integrated fluid flux, we show that the channelized fluid flow was short-lived (2.1 × 10-1 to 1.1 × 101 years) and had a high fluid velocity (2.7 × 10-3 to 4.9 × 10-2 meters second1), which is close to the propagation velocities of seismic events in present-day subduction zones. Our results suggest that the drainage of fluid into the overlying plate occurs as episodic pulses, which may influence the recurrence of megathrust earthquakes.
DOI: ade6674
Source: https://www.science.org/doi/10.1126/sciadv.ade6674