Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Detection Of An Ultra Low Velocity Zone Beneath Central Mexico With Pcp Waveform Modeling, David James Buckley
Detection Of An Ultra Low Velocity Zone Beneath Central Mexico With Pcp Waveform Modeling, David James Buckley
Physics
PcP phases from a Guatemalan earthquake recorded at Nevada stations of the International seismic network (IM) display evidence of anomalous seismic structure at the core-mantle boundary (CMB); in particular, pre- and post-cursor phases to PcP and ScP. The data is examined for evidence of an ultra-low velocity zone (ULVZ) by identifying and modeling precursors to PcP. Precursory arrivals to PcP may be generated by the interaction of PcP with a thin layer above the core-mantle boundary (CMB). One-dimensional modeling demonstrates that standard earth models of the core-mantle boundary, which lack ULVZ structure, cannot produce the observed PcP data. …
Estimates Of The Density Contrast At Earth’S Inner-Core Boundary Beneath Central Mexico, Wade Kelley
Estimates Of The Density Contrast At Earth’S Inner-Core Boundary Beneath Central Mexico, Wade Kelley
Physics
Seismograms recorded in the western United States from a Guatemalan earthquake are examined for matching pairs of PKiKP and PcP waveforms for use in estimating the density contrast at earth’s inner-core boundary via a PKiKP/PcP amplitude ratio analysis. Examination of waveforms from the SN, SC, TA, US and CI arrays finds 68 visually identifiable PKiKP and PcP pairs from which 17 were judged to be of sufficient quality (low signal-to-noise ratio) for use in the PKiKP/PcP amplitude ratio analysis. The epicentral distance range of the selected data spans epicentral distances from 22 – 37 degrees inside of which stations are …
Seismic Detection Of A Low-Velocity Layer Atop The 410-Km Discontinuity: Verification Of An Electromagnetically Detected Layer Of Partial-Melt Atop The 410-Km Discontinuity Beneath Se Arizona, Dwight W. Townsend
Physics
No abstract provided.
Paleomagnetism And Investigation Of 40 Ma Lavas, Liverpool Range, New South Whales, Australia, Nathan M. Padilla
Paleomagnetism And Investigation Of 40 Ma Lavas, Liverpool Range, New South Whales, Australia, Nathan M. Padilla
Physics
The main focus of this project is the continued study of a reversal of the earth’s magnetic field recorded from lavas in the Liverpool Range of New South Whales, Australia. This reverse-to-normal transition, recently dated at ~40 Ma, was first reported in Nature in 1986. [2] In March 2011 some 200+ cores were drilled from several sections about the volcanic range—Jemmy’s Creek, Bald Hill, Rock Creek, Yarraman, and Coolah Tops Road. Here we focus on paleomagnetic findings from samples drilled from the most extensive section, that being along the trail near Jemmy’s Creek. Results from alternating field demagnetization show the …