Ultralow-velocity zone geometries resolved by multidimensional waveform modelling
نویسندگان
چکیده
منابع مشابه
Inferences on ultralow-velocity zone structure from a global analysis of SPdKS waves
[1] Anomalous boundary layer structure at the core-mantle boundary (CMB) is investigated using a global set of broadband SKS and SPdKS waves from permanent and portable broadband seismometer arrays. SPdKS is an SKS wave that intersects the CMB at the critical angle for ScP, thus initiating a diffracted P wave (Pdiff) along the CMB at the core entry and exit locations. The waveshape and timing o...
متن کاملFine-scale ultralow-velocity zone structure from high-frequency seismic array data
[1] Variability of core-mantle boundary (CMB) structure is imaged at the kilometer to tens of kilometers scale by intensive waveform modeling of the ScP phase. Recordings of earthquakes in the Tonga-Fiji subduction zone from the small-aperture (10 km), high-frequency ( 2–4 Hz) Alice Springs Array in central Australia are used to document anomalous ScP waveform variations due to the presence of ...
متن کاملOn the absence of an ultralow‐velocity zone in the North Pacific
[1] Using an unusually large earthquake near the big island of Hawaii, we study the core mantle boundary (CMB) beneath the north‐northeastern Pacific between Hawaii and North America. A dense sampling of the CMB is achieved using the core‐reflected phase PcP recorded at a large number of high‐quality stations in North America, including networks in California, Oregon, Washington, and Alaska, as...
متن کاملRelationship between the viscosity and topography of the ultralow-velocity zone near the core–mantle boundary
Article history: Received 31 December 2009 Received in revised form 14 September 2010 Accepted 17 September 2010 Available online 14 October 2010
متن کاملDetection of an ultralow velocity zone at the core-mantle boundary using diffracted PKKPab waves
[1] Seismic phases diffracted around Earth’s core contain information about lowermost mantle wave speeds. By measuring the slowness of incident diffracted energy from array recordings, seismic velocity along the diffracted path can be estimated. Here we apply this principle to diffraction of the major arc seismic phase PKKPab recorded at the Canadian Yellowknife array to estimate P wave velocit...
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ژورنال
عنوان ژورنال: Geophysical Journal International
سال: 2016
ISSN: 0956-540X,1365-246X
DOI: 10.1093/gji/ggw114