Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 22 for “"Focal mechanisms"”.
-
Focal mechanisms for eastern Tennessee earthquakes, 1981-1983
… the Southern Appalachians, eleven single event focal mechanisms (SEFM) and seven composite focal mechanisms (CFM) are determined from 37 events that occurred in eastern Tennessee between September 1981 and July 1983. Both P-wave polarities and (Sv/P)z amplitude ratios are input to a computer …
-
Determining the focal mechanisms of earthquakes by full waveform modeling
Determining the focal mechanism of an earthquake helps us to better characterize reservoirs, define faults, and understand the stress and strain regime. The objective of this thesis is to find the focal mechanism and depth of earthquakes. This objective is met using a full waveform modeling method …
-
Anisotropy, focal mechanisms, and state of stress in an oilfield : passive seismic monitoring in Oman
… in 5 monitoring wells which can be used for focal mechanism and anisotropy studies. In this Study, I analyse 22 days of data, containing over 600 located events. In the first analysis, 43 reliable fault plane solutions (FPSs) are determined using polarities and amplitudes of direct P-, SV- …
-
Computer derived focal mechanisms for selected earthquakes off the south and west coasts of Turkey
Focal mechanisms of earthquakes, two of them in the Gulf of Antalya and one in the eastern Aegean Sea, were determined by using both P-wave polarities and S-wave polarization angles. Additionally, a focal mechanism solution for a third Gulf of Antalya earthquake was determined from P-wave …
-
Hypocenter Locations and Focal Mechanism Solutions of Earthquakes in the Epicentral Area of the 1886 Charleston, SC, Earthquake
… constrain earthquake hypocenter locations and focal mechanisms. Hypocenter locations of 134 earthquakes indicate a south-striking, west-dipping seismogenic zone in the upper 12 km of the crust. Over 40% of the 66 well-constrained focal mechanisms show reverse faulting on approximately …
-
Moment-radius-stress drop relations and temporal changes in the regional stress from the analysis of small earthquakes in the Matsushiro region, southwest Honshu, Japan
Moment-radius-stress drop relations and composite focal mechanisms were determined for 33 small, shallow, strike slip earthquakes (1.7$MLS4.3) in the Matsushiro region of southwest Honshu, Japan during the period August 1971 through September 1974. Estimates of the scalar moment derived from …
-
The locations and characteristics of the aftershocks of the October 3, 1974, Peruvian earthquake
… km and is indicative of shallow underthrusting. Focal mechanisms are consistent with low angle thrust faulting. A b value of approximately 0.90 was determined for earthquakes within the Peruvian shallow seismic belt (1963-1975) and the aftershock sequence.
-
An Analysis of Focal Parameters with Application to West Texas Micro-Earthquakes
… micro-earthquake distribution, magnitudes and focal mechanism solutions in the Permian Basin. Seismic anisotropy, a typical property in fractured sedimentary rocks, may bias the identification of the location of microseismic events if using isotropic models, a common practice in seismic …
-
Seismic studies of subducted lithosphere
… First, I systematically determined the focal mechanisms and depths of all large-to-moderate sized earthquakes that occurred along the Kuril-Kamchatka in the past 30 years. My results show that the configuration of the subducting slab and the state of strain within the subducted …
-
INTEGRATING GEOPHYSICAL METHODS TO STUDY SUBDUCTION ZONE PROPERTIES, ACTIVE FAULTING IN A VOLCANIC FIELD, AND VOLCANO LANDSLIDE HAZARDS
… I use seismic reflection data, earthquake focal mechanisms, magnetics, and electromagnetics to study three actively deforming regions: 1) the Cascadia subduction zone deformation front in the Pacific NW of the United States, 2) the near surface of the Laguna del Maule volcanic field in the …
-
ΧΑΡΑΚΤΗΡΙΣΤΙΚΕΣ ΠΑΡΑΜΕΤΡΟΙ ΣΕΙΣΜΙΚΗΣ ΠΗΓΗΣ ΜΕ ΤΗ ΜΕΘΟΔΟ ΤΗΣ ΑΝΤΙΣΤΡΟΦΗΣ ΤΩΝ ΚΥΜΑΤΩΝ ΧΩΡΟΥ: ΕΛΛΑΔΑ ΚΑΙ Η ΕΥΡΥΤΕΡΗ ΠΕΡΙΟΧΗ ΤΗΣ
… HAVE BEEN INVERTED SIMULTANEOUSLY, TO GIVE FOCAL MECHANISMS, SOURCE DURATION, RAPTURE COMPLEXITY, SEISMIC MOMENT AND STRESS DROP. FIVE AREAS HAVE BEEN RECOGNIZED IN THE GREEK REGION WITH SEPARATE SOURCE PROPERTIES. EARTHQUAKES CAUSED BY NORMAL FAULTING HAVE RELATIVELY SIMPLE RAPTURE PROCESS …
-
Micro-seismic observations in Leeu Gamka, Karoo, South Africa
… that can be recognised in satellite imagery. The focal mechanisms display strike-slip faulting with the fault plane likely in a NW - SE orientation, consistent with the distribution of the earthquakes. The velocity model was tested by varying the thickness of the Karoo supergroup to investigate …
-
Analyzing the Collective Behavior of Earthquakes to Understand Fault Mechanisms Better
… earthquakes brings valuable information on fault mechanisms. In this thesis, not only do I focus on studying small-to-moderate size earthquakes (M < 4), but I study properties that emerge when many of these earthquakes interact. Many of my conclusions are drawn from observations of earthquake …
-
Mechanical and geological controls on the long-term evolution of normal faults
… wide range of normal fault dips documented with focal mechanisms. In Chapter 3, I show that surface processes can enhance the life span of continental normal faults by reducing the energy cost associated with topography buildup. In Chapter 4, I focus on lithospheric bending induced by fault …
-
Anisotropy and the structural evolution of the oceanic upper mantle
… measured for 78 paths in the east Pacific. The focal mechanisms of the source events were determined from P-wave first motion data and the azimuthal variation in Rayleigh wave amplitudes. In order to describe the observed Rayleigh wave dispersion, both a systematic increase in velocities with …
-
Inversion of seismic source parameters for weak mining-induced and natural earthquakes
… may become not trivial. For this reason, a novel focal mechanism clustering approach is used to automatically classify focal mechanisms, allowing the investigation of the most relevant and repetitive rupture features. The inversion of the mining induced seismicity dataset reveals the repetitive …
-
Investigations of Anomalous Earthquakes at Active Volcanoes
… earthquakes with a specific type of focal mechanism. Vertical compensated-linear-vector-dipole (vertical-CLVD) earthquakes have vertical pressure or tension axes and seismic radiation patterns that are inconsistent with the double-couple model of slip on a planar fault. Prior to this …
-
Fault plane structure of the 1995 Antofagasta Earthquake (Chile) derived from local seismological parameters
… processes. The investigation of 295 aftershock focal mechanism solutions supported the resulting fault plane structure and proposed a 3D similar stress state in the area of the Antofagasta fault plane.
-
Seismic Tomography at Volcanic Rift Zones and Transpressional Plate Boundaries Askja Caldera and Macquarie Island
… postulated based on evidence from gravity, focal mechanisms, and several geological features. However, the tomography model is unable to provide any insight into whether subduction initiation is taking place or not, owing to its limited resolution. The findings from this study contribute to …
-
The role of extension during the evolution of the NW Indian Himalaya
… orogen. In the NW Indian Himalaya, earthquake focal mechanisms, seismites and ubiquitous normal faulting in Quaternary deposits, and regional GPS measurements reveal ongoing E-W extension. In contrast to other extensional structures observed in the Himalaya, this extension direction is neither …
Page 1 of 2