Thesis (M.S.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 69-74).

AN ABSTRACT OF THE THESIS OF SHIBAJI CHATTERJEE, for the Master of Science degree in Geology, presented on APRIL 23, 2009, at Southern Illinois University Carbondale. TITLE: GEOPHYSICAL STUDIES OF THE HERALD-PHILLIPSTOWN FAULT AND OTHER SHALLOW STRUCTURES NEAR CARMI, ILLINOIS. MAJOR PROFESSOR: Dr John L. Sexton Four seismic reflection profiles from the Wabash Valley area of southeastern Illinois successfully imaged the Herald-Phillipstown fault. From the reflection profiles and geophysical well logs, it was interpreted that the Herald-Phillipstown fault is an inverted flower structure. The main fault of the group is a steeply dipping normal fault with associated splay faults that are reverse in character. All the faults of this inverted flower structure are basement penetrating. Structural contour maps as well as maps of various reflector surfaces are prepared using two way travel time as well as depth. These maps show that the reflectors are undulating in character. Also distinct east-west rotational movements of the reflectors are observed along these faults and the main fault shows a curved geometry from south to north. The combination of the rotational movement, the curved nature of the fault plane and the undulating reflectors resulted in variation of offsets along these faults. The nature of faults of the inverted flower structure as observed on the seismic reflection profiles also indicates that there has been a change in the stress regime from extensional to compressional. Structural cross sections were generated using geophysical well logs from drill holes located along these seismic lines to analyze the nature of these faults at shallower depths. From these cross sections numerous shallow faults were observed and many of them can be correlated with those observed on seismic records indicating upward migration of basement penetrating faults into shallow younger sediments. Many of these faults, including the Herald-Phillipstown fault show evidences of reactivation.

Mississippi State University is one of the many public institutions in Mississippi located near a seismic hazard zone known as the New Madrid Seismic Zone (NMSZ). Previous studies reveal the possibility of damage to the campus during an earthquake is in the order of ten percent. Risk assessment for building structures on campus was carried out using HAZUS-MH MR3 software package, for several earthquake scenarios defined to replicate historic and hypothetical earthquake events.The study predicts peak ground accelerations of 0.09g to 0.2g relating to 0.67% to 4.28% building loss ratios respectively, which amounts to a loss of $8.2 million to $53 million. Wood and reinforced masonry buildings show significant resistance to earthquakes compared to concrete and unreinforced masonry buildings. The results of this study suggest that there is a considerable seismic risk to Mississippi State University buildings from a seismic event originating in NMSZ.

Thesis advisor: Alan L. Kafka / This study finds that, in most cases analyzed to date, past seismicity tends to delineate zones where future earthquakes are likely to occur. Network seismicity catalogs for the New Madrid Seismic Zone (NMSZ), Australia (AUS), California (CA), and Alaska (AK) are analyzed using modified versions of the Cellular Seismology (CS) method of Kafka (2002, 2007). The percentage of later occurring earthquakes located near earlier occurring earthquakes typically exceeds the expected percentage for randomly distributed later occurring earthquakes, and the specific percentage is influenced by several variables, including magnitude, depth, time, and tectonic setting. At 33% map area coverage, hit percents are typically 85-95% in the NMSZ, 50-60% in AUS, 75-85% in CA, and 75-85% in AK. Statistical significance testing is performed on trials analyzing the same variables so that the overall regions can be compared, although some tests are inconclusive due to the small number of earthquake sample sizes. These results offer useful insights into understanding the capabilities and limits of CS studies, which can provide guidance for improving the seismicity-based components of seismic hazard assessments. / Thesis (MS) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: 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 the first image of this fault. Forward modeling indicated that the vertical variation of strata across the CU-s would induce a microgravity anomaly of 1.6 mGal. The observed microgravity anomaly survey across the southern boundary is 1.616 ± .004 mGal, and is consistent with the tectonic interpretation. A subsequently acquired seismic-reflection profile corroborates this interpretation. The imaged fault shows approximately 60, 35, and 35 meters of vertical down-to-the-south throw across the tops of Paleozoic, Cretaceous, and Tertiary horizons, respectively. This confirms the CU is not an erosional feature, but a structurally controlled extension of the NMNF.

Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 10, 2009 Includes bibliographical references.

El Perú se encuentra en una zona altamente sísmica, ubicado dentro del cinturón de fuego del pacífico, que contempla aproximadamente el 85% de la actividad sísmica mundial. En nuestro país no existe un historial de eventos sísmicos por lo que, nuestra investigación consiste en la restructuración de una edificación hospitalaria categoría II, de 3 niveles con aislación sísmica en la base, sobre un suelo intermedio; en el distrito y provincia de Huari, Ancash. Se evaluará la viabilidad de construir edificaciones hospitalarias con el método tradicional con el fin de que la entidad pueda elegir la opción que mejor le convenga para su ejecución. Dado que, en nuestro país no existe mayor información cuantitativa y comparativa del comportamiento de hospitales con aislación o sin aislación sísmica para establecer u obligar el uso de aisladores en infraestructuras hospitalarias. Adicionalmente, existen antecedentes de hospitales que fueron diseñados y construidos con el actual código sísmico nacional y que luego de un evento sísmico siguieron operativos. El análisis comparativo, demuestra la capacidad del sistema tradicional que diseñado adecuadamente tendrá la capacidad de cumplir con las exigencias de eventos sísmicos severos, manteniéndose así operativo luego de un sismo; por lo tanto, el sistema aislado sería una solución costosa para un problema sencillo. Sin embargo, el actual código sísmico peruano exige el uso de aisladores sísmicos para toda edificación hospitalaria, especialmente en zonas sísmicas 4 y 3. / Peru is located in a highly seismic zone, located within the Pacific ring of fire, which accounts for approximately 85% of the world's seismic activity. In our country there is no history of seismic events, therefore, our investigation consists of the restructuring of a category II hospital building, with 3 levels with seismic isolation at the base, on an intermediate floor; in the district and province of Huari, Ancash. The feasibility of building hospital buildings with the traditional method will be evaluated so that the entity can choose the option that best suits it for its execution. Given that in our country there is no more quantitative and comparative information on the behavior of hospitals with or without seismic isolation to establish or force the use of isolators in hospital infrastructures. Additionally, there is a history of hospitals that were designed and built with the current national seismic code and that continued operating after a seismic event. The comparative analysis demonstrates the capacity of the traditional system, which, properly designed, will have the capacity to meet the demands of severe seismic events, thus remaining operational after an earthquake; therefore, the isolated system would be an expensive solution to a simple problem. However, the current Peruvian seismic code requires the use of seismic isolators for all hospital buildings, especially in seismic zones 4 and 3. / Tesis

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 seismogenic depth is unbalanced with the surface expression, the Reelfoot Scarp. New high-resolution seismic reflection surveys were acquired across the southwestern back projection of the hypothesized structure at a potential piercing point with the Reelfoot Fault near Proctor City, TN. The resultant images show steeply dipping northeast striking faults with uplifted and arched post-Paleozoic reflectors that extend into the Quaternary sediments, consistent with the findings of the previous surveys. The new imaged faults form a ~500-meter-wide positive flower structure, with vertical displacements of 16 m and 50 m at the top of the Eocene and top of the Paleozoic reflectors, respectively. Results corroborate the Axial Fault extending to the northeast, and provide geological evidence for Reelfoot Fault segmentation. Furthermore, the near-surface SH-wave seismic profiles show the through-going shear deformation has continued into the Quaternary, thus indicating seismogenic strain has not been completely transferred to the Reelfoot Fault, providing additional evidence for accommodating the strain imbalance.

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 earthquake in central China and seismic mitigation policies in use there were considered for potential parallels and learning opportunities. Finally, suggestions for continued scientific research, additional educational opportunities for laymen and engineering professionals, and changes in the application of current earthquake science to public policy in the central United States were outlined with the goal of easing western Kentucky economic issues while maintaining acceptable public safety conditions.

Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Accompanying "this dissertation is a CD-ROM, which contains site amplification and seismic hazard results for each grid point (1974 points) considered in the study. The results have prepared as .txt files. The CD-ROM also contains the maps generated from these estimated results. The maps are prepared as .png files." Title from title screen of thesis/dissertation PDF file (viewed January 28, 2008) Includes bibliographical references (p. 249-269).