Download or read book Double difference Earthquake Relocation of Charlevoix Seismicity Eastern Canada and Implication for Regional Geological Structures written by Meng Pang and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Eastern Canada is located within the North American Plate and, therefore, should have a relatively low rate of earthquake activity compared with interplate boundary. However, large earthquakes do occur in the region, especially in the Charlevoix Seismic Zone (CSZ) located about 100km downstream from Quebec City. In history, the Charlevoix Seismic Zone has been subject to five earthquakes with magnitude 6 or larger (M~7 in 1663; M~6 in 1791 and 1860; M~6.5 in 1870; MS 6.2 +_0.3 in 1925). However, the regional geological structures of the CSZ are not well understood. As one of the most seismically active region in Eastern Canada, the earthquakes in the CSZ are a significant hazard. Therefore, improved knowledge of distribution and seismic characteristics of these events provides a great benefit for understanding the seismic hazard of the CSZ. In this thesis, I apply earthquake location technique on discovering fault features in CSZ. Earthquake location, as a basic technique in seismometry, plays an important role in the studying of fault structures. The double-difference earthquake location algorithm (HYPODD) is able to get high-resolution hypocenter locations by introducing the residual between observed and calculated travel times between two events, and removing the effects of the un-modeled velocity structure. In this thesis, the resolution of double-difference location algorithm was analyzed using the seismic data of Canadian National Seismograph Network(CNSN) from Jan,1988 to Oct, 2010. The double-difference earthquake location algorithm was used to relocate more than 400 earthquakes in the Charlevoix seismic zone (CSZ), using a layered velocity model. The location results of initial catalog data and double-difference relocation results visually compare with each other, and the cross section of the northeast part in CSZ shows two nearly parallel faults dipping about 60 degree to the southeast. This provides evidence that there are minor rifting geological features underneath the St-Laurence River." --

Download or read book WAVEFORM AND GEODYNAMIC MODELING OF SEISMICITY ASSOCIATED WITH THE CHARLEVOIX SEISMIC ZONE written by Oluwaseun Idowu Fadugba and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Charlevoix seismic zone (CSZ) is the most seismically active region in eastern Canada. It is located within the Late Proterozoic-Early Cambrian St. Lawrence rift zone in southeastern Quebec. The location was also the site of a Devonian impact crater. The CSZ poses a high seismic risks due to its seismicity compared to the other seismic zones in the area and its proximity to densely populated cities (e.g., Quebec City, Ottawa, and Montreal). It is also responsible for much of the seismic hazard in New England. Previous studies in the CSZ observed a maximum compressive stress orientation of N86, which represents a 32 clockwise rotation from the regional orientation determined from nearby boreholes (i.e., 54). Dividing the CSZ into two clusters, one northwest of the SLF and one to the southeast. The stress inversion for earthquakes in the NW cluster) and for earthquakes in the SE cluster yielded orientations of N55 and N101, respectively. Previous studies also suggest two sets of geometries for the rift faults. One set has a uniform dip of 70SE for all three faults while the other has 65, 40, and 40SE, from north to south, respectively. My research focuseson the waveform and geodynamic modeling of seismicity associated with the CSZ by examining the characteristics of the earthquakes usingfocal mechanisms and wave propagation, stress inversion, clustering analyses and numerical models. Firstly, the seismological information offers an important database to be examined with geodynamic modeling, using PyLith, to investigate the combined effects of the preexisting structures and regional stresses on earthquake activity and stress rotations in the CSZ. We conclude that the CSZ seismicity is due to the combined effects of the rift faults and the impact structure and that the planar faults we considered in the model can explain the observed seismicity but not the stress rotations. We also conclude that an impact structure 4 times less elastically stiff than the surrounding crust can explain the seismicity in the CSZ. Secondly, part of my research involves determining focal mechanisms ofrelocated earthquakesin the CSZ with M 2 usingwave polarities and amplitude. I perform stress inversion using the new focal mechanisms and investigate the change in maximum stress orientation laterally and with depth. Stress inversion using all focal mechanisms shows that the orientation is N103, in contrast to N86 from previous work, with reverse faulting dominating. We observed a orientation of N73 within the impact zone compared to N106 outside the zone. A distinct systematic clockwise change in orientation of 44 is observed as a function of source depth from the surface to 20 km, changing from N83 to N127. We suggest that seismicity and the observed stress rotations of the CSZ are controlled by velocity heterogeneity and rock stiffness, including the impact structure, and pre-existing fault structure within a stress field generated by both plate tectonic forces and glacial rebound. Lastly, this study also uses clustering analyses of earthquake locations to constrain the geometry of the rift fault better using a modifiedversion of the Optimal Anisotropic Dynamic Clustering (OADC) algorithm. Our fault model shows dips of 65, 39 and 47 for the three fault system in the CSZ near the impact but changes to a 65-69-64 dipping fault geometry in the NE end of the CSZ. Our model also shows the geometry of some bounding faults associated with the damage zone of the impact structure. This study presents a realistic but simplified fault geometry of the CSZ and suggests a combination of the type of the two fault geometries found in previous studies..

Download or read book Double Difference Earthquake Relocation After Full Waveform Discrimination written by Prabhat Shrestha and published by . This book was released on 2015 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: The estimation of the hypocentres of seismic events is crucial in the interpretation of subsurface structure and tectonics. The principle objective was to refine estimates of these hypocentres by analysing the full seismic wave field - rather than the P or P and S waves alone - of a cluster of events. The events we examine were originally located using their P and S wave arrivals on borehole seismometers, as part of a CO2 sequestration project from the Aneth Oil field in Utah, USA. These events were then clustered based on their P wave similarity alone. We further sub-clustered these events based on their full waveform. Similar results were obtained from the full-waveform analysis in both time and frequency domains. We then compared earthquake relocation based on double-difference tomography of the original cluster, and relocation of the events, per sub-cluster. The double difference algorithm was applied in software package HypoDD. Six sub-clusters arose from the full waveform analysis on a possible "en echelon" structure with a north-west south-east alignment. Total-cluster relocations converged to the centroid of this cluster; these hypocentre locations were deemed less likely than the original locations, given prior knowledge of the geology. However, relocations were more refined when HypoDD was run for individual clusters. Individual cluster relocations appeared to condense within their sub-cluster centroid, the pre-processing step of sub-clustering retained en echelon structure and the north-west southeast alignment, preserving spatial information. This supports our assumption that the initial locations identified using correlated P arrivals were accurate at the outset. HypoDD's inability to accept negative station elevations in conjunction with a layered velocity model prompted us to shift the station and event locations above the surface. The presence of a low velocity zone also prompted the adjustment of the velocity model such that this zone was eradicated. This was achieved by adjusting the velocity model such that the velocity increased in conjunction with the depth throughout. Shifting the location of the earthquakes above the surface may have affected our hypocentre relocations but our epicentre relocation accuracy was kept intact. Our alteration of the geological structure through the adjustment of the low velocity zone may have also affected our hypocentre locations. However, our aims of witnessing the sub-clusters converge while keeping their en echelon structure and north-west south-east alignment was fulfilled. This suggests that the errors which originate from these approximations were minimal. The application of the double difference algorithm on a known sub-cluster at a CO2 sequestration project at Aneth field refines the location of epicentre estimations, but maintains the structure of fault systems hidden in the full seismic waveforms. In the future, further knowledge of the subsurface will allow us to better reconstruct the low velocity zone. This may result in more refined epicentre and hypocentre relocations. These newly found locations could be mapped with known fault structures, in order to find new fault regimes within these structures.

Download or read book Spring Meeting written by American Geophysical Union. Meeting and published by . This book was released on 1993 with total page 1148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of Seismicity and Structural Geology written by John Edward Brooks and published by . This book was released on 1960 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geological Abstracts written by and published by . This book was released on 1988 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stress in the Lithosphere written by American Geophysical Union and published by . This book was released on 1992 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seismicity Processes in the Charlevoix Seismic Zone Eastern Canada written by Azadeh Fereidoni and published by . This book was released on 2014 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Charlevoix Seismic Zone (CSZ) is the most seismically active region in eastern Canada, based on the historical and current rate of activity. Several papers contend that the current seismicity in the CSZ represents long-lived aftershock sequences of the 1663 M~7 earthquake, in which the aftershock activity has persisted for hundreds of years. The aim of this thesis is to explore the influence of the 1663 earthquake on the current seismicity in the CSZ. The first part of the thesis has focused on developing a comprehensive earthquake database required for analysis of seismicity. The second part of the thesis has been devoted to characterization of seismicity in the CSZ in both time and space, with the goal of developing greater insight into the nature of intraplate seismicity in this region. The evidence from statistical analysis suggests that the current seismicity in the CSZ is not predominantly composed of the aftershock activity of past large earthquakes; the ongoing seismicity is therefore expected to continue in the region, and the zone should be considered an ongoing source of seismic hazard. However, I emphasize that this does not eliminate the possibility that earthquake activity in Charlevoix is still influenced by the stress changes imparted by the 1663 earthquake in the surrounding crust. The Coulomb stress analysis used in the present thesis shows that the stress triggers and shadow cast by the 1663 earthquake still exert influence on earthquake occurrence in Charlevoix after centuries.

Download or read book Seismological Research Letters written by and published by . This book was released on 2004 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book XIX General Assembly Vancouver Canada August 9 22 1987 written by International Union of Geodesy and Geophysics. General Assembly and published by . This book was released on 1987 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Union IAG IASPEI written by International Union of Geodesy and Geophysics. General Assembly and published by . This book was released on 1987 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fire Following Earthquake written by Charles Scawthorn and published by ASCE Publications. This book was released on 2005-01-01 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prepared by the Technical Council on Lifeline Earthquake Engineering of ASCE. This TCLEE Monograph covers the entire range of fire following earthquake (FFE) issues, from historical fires to 20th-century fires in Kobe, San Francisco, Oakland, Berkeley, and Northridge. FFE has the potential of causing catastrophic losses in the United States, Japan, Canada, New Zealand, and other seismically active countries with wood houses. This comprehensive book on FFE and urban conflagrations provides state-of-the-practice insight on unique issues, such as large diameter flex hose applications by fire and water departments. Topics include: History of past fires; Computer modeling of fire spread in the post-earthquake urban environment; Concurrent damage and fire impacts for water, power gas, communication and transportation systems; Examples of reliable water systems built or designed in San Francisco, Vancouver, Berkeley, and Kyoto; Use of large diameter (5 in.) and ultralarge diameter (12 in.) flex hose for fire fighting and water restoration; and Cost-effectiveness of various FFE mitigation strategies, with a detailed benefit-cost model. Water utility engineers, fire fighting professionals, and emergency response planners will benefit from reading this book.

Download or read book United States Earthquakes written by and published by . This book was released on 1977 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Continental Intraplate Earthquakes written by Seth Stein and published by Geological Society of America. This book was released on 2007-01-01 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This volume brings together a sampling of research addressing issues of continental intraplate earthquakes, including a core of papers from special sessions held at the spring 2004 Joint Assembly of the American and Canadian Geophysical Unions in Montreal. Papers address the broad related topics of the science, hazard, and policy issues of large continental intraplate earthquakes in a worldwide context. One group of papers addresses aspects of the primary scientific issue--where are these earthquakes and what causes them? Answering this question is crucial to determining whether they will continue there or migrate elsewhere. A second group of papers addresses the challenge of assessing the hazard posed by intraplate earthquakes. Although it may be a very long time before the scientific issues are resolved, the progress being made is helping attempts to estimate the probability, size, and shaking of future earthquakes, and the uncertainty of the results. A third group of papers explores the question of how society should mitigate the possible effects of future large continental intraplate earthquakes. Communities around the world face the challenge of deciding how to address this rare, but real, hazard, given the wide range of other societal needs. Continental intraplate earthquakes will remain a challenge to seismologists, earthquake engineers, policy makers, and the public for years to come, but significant progress toward understanding and addressing this challenge is now being made."--Publisher's website.

Download or read book NEHRP Recommended Provisions National Earthquake Hazards Reduction Program for Seismic Regulations for New Buildings and Other Structures Commentary written by United States. Federal Emergency Management Agency and published by . This book was released on 2001 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Natural Catastrophe Risk Management and Modelling written by Kirsten Mitchell-Wallace and published by John Wiley & Sons. This book was released on 2017-04-24 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers both the practical and theoretical aspects of catastrophe modelling for insurance industry practitioners and public policymakers. Written by authors with both academic and industry experience it also functions as an excellent graduate-level text and overview of the field. Ours is a time of unprecedented levels of risk from both natural and anthropogenic sources. Fortunately, it is also an era of relatively inexpensive technologies for use in assessing those risks. The demand from both commercial and public interests—including (re)insurers, NGOs, global disaster management agencies, and local authorities—for sophisticated catastrophe risk assessment tools has never been greater, and contemporary catastrophe modelling satisfies that demand. Combining the latest research with detailed coverage of state-of-the-art catastrophe modelling techniques and technologies, this book delivers the knowledge needed to use, interpret, and build catastrophe models, and provides greater insight into catastrophe modelling’s enormous potential and possible limitations. The first book containing the detailed, practical knowledge needed to support practitioners as effective catastrophe risk modellers and managers Includes hazard, vulnerability and financial material to provide the only independent, comprehensive overview of the subject, accessible to students and practitioners alike Demonstrates the relevance of catastrophe models within a practical, decision-making framework and illustrates their many applications Includes contributions from many of the top names in the field, globally, from industry, academia, and government Natural Catastrophe Risk Management and Modelling: A Practitioner’s Guide is an important working resource for catastrophe modelling analysts and developers, actuaries, underwriters, and those working in compliance or regulatory functions related to catastrophe risk. It is also valuable for scientists and engineers seeking to gain greater insight into catastrophe risk management and its applications.

Download or read book History of Jefferson County Illinois written by William Henry Perrin and published by . This book was released on 1883 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: