AGU Editor's Highlight & Overseas Study Information（Mar 22-Mar 28, 2019）-北京大学海洋研究院

AGU Editor's Highlight & Overseas Study Information（Mar 22-Mar 28, 2019）

2019-03-28 10:59:47

本周发布的为美国地球物理联合会AGU EOS (Earth & Space Science News) 的最新Editor's Highlight和美国、新西兰、瑞典、德国、加拿大地区的PhD, Postdoc, 访问学者的招聘信息。本周还内附NASA Frontier Development Lab的实习机会哦！欢迎关注我们！

Editor's Highlight:

Follow The 'Hum': The Seismic Signal of Pacific Ocean Storms

Have you ever noticed that the Earth is humming? Seismologists have! Discover how individual storms in the northern Pacific Ocean generate a long-period seismic signal.

SOURCE: Geochemistry, Geophysics, Geosystems

Plots of power spectral density (a measure of how much energy is present at different frequencies) at ocean bottom seismometers AXCC1 (top panel), located offshore Cascadia, and MOBB (bottom panel), located in Monterey Bay, California. The x axis represents time, labeled as days of the year 2015, while the y axis represents wave periods, in seconds (labeled at left). Colors indicate the power spectral density in decibels (dB), with red colors indicating more energy and blue colors indicating less energy. The dashed white line indicates the first appearance of strong energy at relatively long periods due to a storm impacting the Cascadia region of the west coast of the United States. Small gray dots indicate the timing of relatively large earthquakes globally, with the size of the earthquakes (on the moment magnitude scale, Mw) shown on the right side of the plot. Credit: Maurya et al. [2019], Figure 5 lower right panels

The Earth's "hum" is an enigmatic, low-frequency signal that has been known to seismologists for some time, but whose source has remained poorly understood. It is generally thought that the hum is generated in ocean basins through the interaction of infragravity waves with the seafloor. However, the hum is not evenly distributed in space or time, and the exact mechanisms through which it is generated remain unclear.

Maurya et al. [2019] combine seismic observations with ocean wave height data to track two large storms in the Pacific Ocean and delineate how each of them generates hum. Their work shows that the distribution of Earth's hum sources strongly depends on the propagation characteristics of the corresponding storms and how the storms interact with the coastline. This study has important implications not only for how we understand the generation of infragravity waves in the ocean, but also for studies of deep Earth structure that take advantage of the hum signal.

Citation: Maurya, S., Taira, T., & Romanowicz, B. [2019]. Location of seismic "hum" sources following storms in the North Pacific Ocean. Geochemistry, Geophysics, Geosystems, 20. https://doi.org/10.1029/2018GC008112

—Maureen Long, Editor, Geochemistry, Geophysics, Geosystems

国外学习、实习、工作机会：

1. Postdoc-Understanding Habitability of Redox-Active Hydrothermal Systems in Planetary Environments

Pasadena, California (US)

Jet Propulsion Laboratory

https://findajob.agu.org/job/8009530/postdoc-understanding-habitability-of-redox-active-hydrothermal-systems-in-planetary-environments/

2. PhD Opportunity-Volcano Geophysics

Auckland, New Zealand

School of Environment, University of Auckland

https://findajob.agu.org/job/8009514/phd-opportunity-volcano-geophysics/

3. NASA Frontier Development Lab Intern 2019

Mountain View, California (US)