报告地点：腾讯会议ID：159 594 926
报告时间：2022-05-27 从 15:00 到 17:00
报告人：沈智超
报告人简介：
沈智超，分别于2013和2016年在中国科学技术大学地空学院获得地球物理专业学士和硕士学位。2022年获得美国加州理工学院地球物理专业博士学位，2022下半年将任伍兹霍尔海洋研究所博士后职位。主要研究方向包括俯冲板片多尺度结构成像，中深源地震震源机制以及分布式光纤在地震学中的应用。在GRL, PEPI, AGU Advance, EPSL, GJI 等期刊发表论文十余篇，其中一作/通讯作者论文3篇，于2019年荣获AGU杰出学生报告奖，曾是JGR，SRL，BSSA等学术期刊审稿人。
报告题目：High-resolution monitoring of vadose zone soil moisture with distributed acoustic sensing
报告内容简介
Water in the critical zone is vital but its current monitoring techniques are mostly for surface water content with few probing the vadose zone. To fill in this gap, timelapse seismology is a complimentary tool but suffers from large conventional sensor spacing. By transforming existing optic-fiber cables into thousands of seismic sensors, the emerging distributed acoustic sensing (DAS) technology provides an affordable and scalable solution for deploying large aperture and ultra-dense seismic arrays, thus feasible for the vadose zone monitoring. With two years of ambient noise recorded on the Ridgecrest DAS array, the time-lapse images of seismic changes (dv/v) reveal an unprecedented high-resolution spatiotemporal evolution of water saturation in vadose zone. A striking correlation between the dv/v amplitude and the sedimentary thickness is observed, while the frequency analysis of dv/v measurements suggests an uppermost 10 m hydrologic source as the cause for dv/v temporal variability. Our results indicate the great potential of DAS for long-term subsurface water monitoring.