Recent News

  • Nov 30, 2018: We observe strong long-period hydro-related localized long-period crustal deformations in the Plate Boundary Observatory (PBO) borehole strainmeters. This paper is now available on Geophysical Research Letters.

  • Sep 12, 2018: We detect seismicity triggered after North Korea’s 3 September 2017 nuclear test and explore its triggered mechanism. This paper is now available on Seismological Research Letters.

  • Jun 26, 2018: We observe that seismicty was induced by simultaneous abrupt changes of injection rate and well pressure in Hutubi (China) gas field. This paper is now available on Journal of Geophysical Research: Solid Earth.

  • Apr 18, 2018: We build the first database of stress changes on the Earth from 2000 to 2017 in a global scale and at various depths, by considering six loading forces: hydrological loading, atmospheric pressure, ocean water (including tides and nontidal variation), solid lunisolar tides, pole tide, and postglacial rebound. This paper is now available on Journal of Geophysical Research: Solid Earth.

  • Sep 23, 2017: Our observation shows that daily-cycle S1 strain tide in the Plate Boundary Observatory (PBO) borehole strainmeters is 1–2 orders larger than theoretical prediction, and is caued by elastic loading of barometric pressure and thermoelastic deformation by surface temperature. This paper is now available on Journal of Geophysical Research: Solid Earth.

Projects

Strainmeter Observation

Project Focuses:

  1. Dectection and analysis of crustal defomation signals in Plate Boundary Observatory (PBO) borehole strainmters
  2. Analytic and numerical modeling of the deformation
  3. Physical mechanisms for the deformation

Stress Calculation

Project Focuses:

  1. Quantitative estimation of Earth’s loading forces
  2. Construction of a physcial framework for Earth’s response to loading forces
  3. Culculation of loading-induced stress changes in Earth’s interior
  4. Relationship between seimicity and loading-induced stress

Triggered/Induced Seismicity

Project Focuses:

  1. Detection and location of seismic events
  2. Seismic source characteristics
  3. Physical and statistical relationship between seismic events and driving forces
  4. Triggered/induced mechanisms for seismic events

Selected Publications

  • We observe a localized long-period (3–4 years) hydro-related deformation in Plate Boundary Observatory borehole strainmeters in California.
  • The strain exhibits amplitude up to 10e–6 and is correlated with pore pressure change and cumulative rainfall in both time and shape.
  • The long-period strain can be explained by a rainfall – hydrological diffusion – poroelastic deformation mechanism.
Geophyscial Research Letters, 2018

  • We establish a preliminary global database of the loading-induced stress changes on the Earth from 2000 to 2017.
  • We consider six loading forces: hydrological loading, atmospheric pressure, ocean water, lunisolar tides, pole tide and postglacial rebound.
  • The induced stress fields exhibit different geographic, temporal and depth variations for different loading forces.
Journal of Geophysical Research: Solid Earth, 2018

  • Tidal signals are analyzed in the Plate Boundary Observatory (PBO) borehole strainmeter data in western North America.
  • Abnormally strong (1–2 orders larger than theoretical prediction) daily-cycle S1 strain tide is observed in the strainmeters.
  • The strong S1 tide is mainly caused by elastic loading of barometric pressure and thermoelastic deformation induced by surface temperature.
Journal of Geophysical Research: Solid Earth, 2017

Recent Publications

(2018). Triggered seismicity associated with North Korea's 3 September 2017 nuclear test. Seismological Research Letters.

Project Source Document

(2018). Seismicity induced by simultaneous abrupt changes of injection rate and well pressure in Hutubi gas field. Journal of Geophysical Research: Solid Earth.

Project Source Document

(2018). Loading-induced Earth's stress change over time. Journal of Geophysical Research: Solid Earth.

Project Source Document

(2017). Abnormally strong daily-cycle S1 strain tide: Observation and physical mechanism. Journal of Geophysical Research: Solid Earth.

Project Source Document

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