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Full-Text Articles in Physical Sciences and Mathematics
Integrated Geophysical Investigation Of Near-Surface Faults - Sassafras Ridge, New Madrid Seismic Zone, Usa, Cooper Cearley
Integrated Geophysical Investigation Of Near-Surface Faults - Sassafras Ridge, New Madrid Seismic Zone, Usa, Cooper Cearley
Theses and Dissertations--Earth and Environmental Sciences
The New Madrid Seismic Zone (NMSZ) is a large source of seismic hazard within the central and eastern United States. Seismogenic source parameters such as active fault location, slip rate, total displacement, and strain accommodation is poorly constrained due to the masking effect of the Mississippi Embayment sediment and agricultural practices on structures and surface expressions. Consequently, noninvasive geologic and geophysical investigation of the subsurface is needed to characterize seismogenic sources. Recent investigation of the Reelfoot Fault found that there is a strain accommodation enigma between the dextral offset at seismogenic depth versus the surface expression, Reelfoot Scarp. This strain …
Extension Of A Quaternary-Active Shear Zone Across The Reelfoot Fault Stepover Arm: Evidence From P- And Sh-Wave Seismic Reflection Imaging, Brooks Rosandich
Extension Of A Quaternary-Active Shear Zone Across The Reelfoot Fault Stepover Arm: Evidence From P- And Sh-Wave Seismic Reflection Imaging, Brooks Rosandich
Theses and Dissertations--Earth and Environmental Sciences
Many seismic hazard source parameters such as slip rate, total displacement, strain accommodation, geographic fault location, etc. are poorly constrained in the New Madrid seismic zone (NMSZ). This is in large part due to the masking effect of the thick Mississippi embayment sediment package on seismogenic structures and features. Consequently, much of the subsurface geologic characterization needed for understanding seismic hazard sources requires geophysical imaging. Recent seismic reflection surveys 12 km NE of the Reelfoot Fault stepover arm of the NMSZ have suggested a northeast-oriented transpressional fault zone extending across the Reelfoot Fault stepover arm where its dextral displacement at …
Integrated Seismic-Reflection And Microgravity Imaging Across The Southern Boundary Of The Charleston Uplift, New Madrid Seismic Zone, Usa, Drew D. Burford Jr.
Integrated Seismic-Reflection And Microgravity Imaging Across The Southern Boundary Of The Charleston Uplift, New Madrid Seismic Zone, Usa, Drew D. Burford Jr.
Theses and Dissertations--Earth and Environmental Sciences
The Charleston Uplift (CU), a 30-km-long by 7-km-wide, N46°E-oriented subsurface geologic anomaly in the northern Mississippi embayment near Charleston, Missouri, exhibits up to 36 m of vertical relief across the Paleogene/Quaternary unconformity. Subsurface structural relief, along with the CU’s coincident boundary alignment with contemporary microseismicity and the New Madrid North Fault (NMNF), suggest a structural origin. Subsequent seismic soundings indicate vertical structural relief is present in Cretaceous and Paleozoic horizons, supporting the fault-controlled origin. The southern boundary (CU-s) had not been investigated, nor had any direct fault images been acquired. Integrated microgravity and seismic-reflection methods across the inferred CU-s establish …
Science And Public Policy Of Earthquake Hazard Mitigation In The New Madrid Seismic Zone, Alice M. Orton
Science And Public Policy Of Earthquake Hazard Mitigation In The New Madrid Seismic Zone, Alice M. Orton
Theses and Dissertations--Earth and Environmental Sciences
In the central United States, undefined earthquake sources, long earthquake recurrence intervals and uncertain ground motion attenuation models have contributed to an overstatement of regional seismic hazard for the New Madrid Seismic Zone on the National Seismic Hazard Maps. This study examined concerns regarding scientific uncertainties, overly stringent seismic mitigation policies and depressed local economy in western Kentucky through a series of informal interviews with local businessmen, public officials, and other professionals in occupations associated with seismic mitigation. Scientific and relative economic analyses were then performed using scenario earthquake models developed with FEMA’s Hazus-MH software. Effects of the 2008 Wenchuan …
Sh-Wave Refraction And Reflection Investigation Of Quaternary Geology―Central United States Seismic Observatory, Carrington L. Wright
Sh-Wave Refraction And Reflection Investigation Of Quaternary Geology―Central United States Seismic Observatory, Carrington L. Wright
Theses and Dissertations--Earth and Environmental Sciences
The Central United States Seismic Observatory (CUSSO) consists of an array of vertical strong motion accelerometers and medium period seismometers that penetrate 585 m into the Mississippi Embayment sediments and terminates into Paleozoic bedrock. The array is located in the New Madrid Seismic Zone within the upper embayment. The thick unconsolidated Quaternary sediments have the potential to influence strong motions; understanding how these sediments affect ground motion is the goal of the CUSSO array. Nine SH-wave refraction and five P-wave common midpoint reflection surveys were collected within a 1 km radius around the CUSSO borehole in order to characterize the …