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GPS Event Calendar

Online Seminars & Events

Week of June 14, 2021
MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY
DIX Planetary Science Seminar
4:00 pm to 5:00 pm
Environmental Science and Engineering Seminar
4:00 pm to 5:00 pm
Geoclub Seminar Series
4:00 pm to 5:00 pm
Seismo Lab Seminar
4:00 pm to 5:00 pm

Division Seminar

Mondays from 12:00pm to 1:00pm
For more information, please contact: Leticia Calderon

Seminars will return starting September 27th.

DIX Planetary Science Seminar

Tuesdays at 4:00 pm
For more information, please contact Aida Behmard

Environmental Science and Engineering Seminar

Wednesdays from 4:00pm to 5:00pm
For more information, please contact: Bronagh Glaser

Geoclub Seminar Series

Thursdays from 4:00pm to 5:00pm
For more information, please contact: Sarah Zeichner

Seismo Lab Seminar

Fridays from 4:00 pm to 5:00 pm
For more information, please contact Seismo Seminar Committee.

"A hard rain's gonna fall, and what will happen to the lithosphere?"

Kosuke Heki (Hokkaido University)

Abstract: A tropical cyclone transports a large amount of sea water to land as water vapor. The water becomes a torrential downpour, and the rainwater temporarily staying on land depresses the solid earth as a load. I first study the super typhoon Hagibis in 2019 October using a dense network of continuous global navigation satellite system (GNSS) stations in Japan as a sensor of both water vapor and ground subsidence. We first map the distribution of water vapor using the delays of microwave signals from the satellites during the typhoon passage. The water vapor centroid moved together with the precipitation centroid along the path of the eye of the typhoon. With the Green's function describing crustal subsidence as a function of distance from a unit load, we can infer the total amount of rainwater on land. The estimated amount of rainwater, however, far exceeded the cumulative rainfall on land. We consider this paradox caused by local-scale concentration of rainwater around the Japanese GNSS stations. They are deployed along valleys and within basins where rainwater gathers, and topographic amplification of subsidence occurs. Second, I study heavy rain episodes in SW Japan occurring every summer 2017-2020 due to stationary weather fronts. I found volumetric subsidence of about 1 cubic kilometer occurs by rain of ~10 Gt in a day. This recovers with a time constant of ~1 day owing to steep slopes of Japanese rivers. This linearity breaks down, however, for rains exceeding 10 Gt/day possibly by damages to the river levees. The first half of the talk was just published online 15 May 2021. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JB021845?af=R

Thesis Defense Seminars

For more information, please contact Julie Lee; julielee@caltech.edu