Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Publication
- Publication Type
Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Mantle Transition Zone Discontinuities Beneath The Contiguous United States, Stephen S. Gao, Kelly H. Liu
Mantle Transition Zone Discontinuities Beneath The Contiguous United States, Stephen S. Gao, Kelly H. Liu
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Using over 310,000 high-quality radial receiver functions recorded by the USArray and other seismic stations in the contiguous United States, the depths of the 410 km and 660 km discontinuities (d410 and d660) are mapped in over 1,000 consecutive overlapping circles with a radius of 1⁰. The average mantle transition zone (MTZ) thickness for both the western and central/eastern U.S. is within 3 km from the global average of 250 km, suggesting an overall normal MTZ temperature beneath both areas. The Pacific Coast Ranges and the southern Basin and Range Province are underlain by a depressed d410, indicating higher-than-normal temperature …
Seismic Imaging Of Mantle Transition Zone Discontinuities Beneath The Northern Red Sea And Adjacent Areas, A. A. Mohamed, Stephen S. Gao, A. A. Elsheikh, Kelly H. Liu, Youqiang Yu, R. E. Fat-Helbary
Seismic Imaging Of Mantle Transition Zone Discontinuities Beneath The Northern Red Sea And Adjacent Areas, A. A. Mohamed, Stephen S. Gao, A. A. Elsheikh, Kelly H. Liu, Youqiang Yu, R. E. Fat-Helbary
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The dramatic asymmetry in terms of surface elevation, Cenozoic volcanisms and earthquake activity across the Red Sea is an enigmatic issue in global tectonics, partially due to the unavailability of broad-band seismic data on the African Plate adjacent to the Red Sea. Here, we report the first comprehensive image of the mantle transition zone (MTZ) discontinuities using data from the Egyptian National Seismic Network, and compare the resulting depths of the 410 and 660-km discontinuities with those observed on the Arabian side. Our results show that when a standard earth model is used for time-to-depth conversion, the resulting depth of …
A Uniform Database Of Teleseismic Shear Wave Splitting Measurements For The Western And Central United States, Kelly H. Liu, Ahmed Elsheikh, Awas Lemnifi, Uranbaigal Purevsuren, Melissa Ray, Hesham Refayee, Bin B. Yang, Youqiang Yu, Stephen S. Gao
A Uniform Database Of Teleseismic Shear Wave Splitting Measurements For The Western And Central United States, Kelly H. Liu, Ahmed Elsheikh, Awas Lemnifi, Uranbaigal Purevsuren, Melissa Ray, Hesham Refayee, Bin B. Yang, Youqiang Yu, Stephen S. Gao
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
We present a shear wave splitting (SWS) database for the western and central United States as part of a lasting effort to build a uniform SWS database for the entire North America. The SWS measurements were obtained by minimizing the energy on the transverse component of the PKS, SKKS, and SKS phases. Each of the individual measurements was visually checked to ensure quality. This version of the database contains 16,105 pairs of splitting parameters. The data used to generate the parameters were recorded by 1774 digital broadband seismic stations over the period of 1989-2012, and represented all the available data …
Doing More With Short Period Data: Determining Magnitudes From Clipped And Over-Run Seismic Data At Mount St. Helens, John J. Wellik Ii
Doing More With Short Period Data: Determining Magnitudes From Clipped And Over-Run Seismic Data At Mount St. Helens, John J. Wellik Ii
Dissertations, Master's Theses and Master's Reports - Open
How can we calculate earthquake magnitudes when the signal is clipped and over-run? When a volcano is very active, the seismic record may saturate (i.e., the full amplitude of the signal is not recorded) or be over-run (i.e., the end of one event is covered by the start of a new event). The duration, and sometimes the amplitude, of an earthquake signal are necessary for determining event magnitudes; thus, it may be impossible to calculate earthquake magnitudes when a volcano is very active. This problem is most likely to occur at volcanoes with limited networks of short period seismometers. This …