RESEARCH
HOME            PUBLICATIONS            RESEARCH   

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Theoretical Wave Propagation

Whether through the use of finite frequency kernels or fully numerical approaches, the Global Seismology Group continues its commitment to applying the latest theoretical and computational advances to the study of Earth structure.  

Global Elastic Waveform Vectorial Tomography

The Global Seismology Group has pioneered the use of full-waveform tomography using finite frequency kernels (see Theory below), and we have produced a number of models of the velocity and anisotropic structure of the mantle.  

Global Anelastic Waveform Tomography

We have have been a trailblazer in using tomographic techniques to map the distribution of seismic attenuation in the Earth's mantle.   

Regional Vectorial Tomography

Taking advantage of the unprecedented coverage of North America made available by recent PASSCAL and USARRAY deployments, we have undertaken a series of studies looking at the velocity and anisotropic structure beneath North America.    

Study of D" Region

The mantle's lower thermal boundary layer, also known as D", has been the subject of waveform modeling and tomographic study by the Global Seismology Group. Our investigations have revealed strong seismic heterogeneity in D", and have provided insight into flow occurring within and the thermochemical state of this fascinating region of the Earth.   

Study of the Core

Using observations of free oscillations and higher frequency body waves, the Global Seismology Group has probed Earth's very center. Our study of this remotest part of our planet has helped constrain its dynamics and thermochemical state.

The Earth's Hum

The Global Seismology Group has been actively researching the processes by which seismic waves are excited, be they earthquakes themselves or ocean-atmosphere-lithosphere interactions giving rise to Earth's evepresent "hum".  

Instrumenting the Ocean Floor

In an effort to gain experience in deploying and maintaining ocean-bottom seismometers, a three component very broadband seismometer package (CMG-1T), recording system, as well as auxiliary differential pressure gauge (DPG) and current meter, were installed on the seafloor, in Monterey Bay, 40 km off-shore, at 1000m water depth. 

 


Recent Highlights: 

 

  • Depth distribution of anisotropy in the continental upper mantle, published in Nature (2007)

  • Short wavelength topography on the inner core boundary, published in PNAS (2007) 

     

    Detection and identification of PKJKP, published in Science (2005)
     

    Origin of the Earth's "hum", published in Nature (2004)
     

    Radial anisotropy at the base of the mantle, published in Science (2004) 

     

    Anisotropy and thickness of the lithosphere, published in Nature (2003) 

      

    Superplumes from the core mantle boundary to the lithosphere, published in Science (2002)