A glassy Lowermost Outer Core
... differential travel time residuals, with respect to the spherically symmetric model ak135, are consistently smaller than two seconds along the north-south paths sampled. Axially symmetric models of inner core seismic anisotropy with fast axis parallel to the Earth’s rotation axis require only (0.4±0 ...
... differential travel time residuals, with respect to the spherically symmetric model ak135, are consistently smaller than two seconds along the north-south paths sampled. Axially symmetric models of inner core seismic anisotropy with fast axis parallel to the Earth’s rotation axis require only (0.4±0 ...
Long-term creep-rate changes and their causes
... earthquake. An interesting exception to this is that creeprate changes appear to start a considerable time before large and moderate-size earthquakes. This may be the case before the Loma Prieta event and especially for the 1961 quakes [see Burford, 1988; Wesson, 1988]. However, one can only specula ...
... earthquake. An interesting exception to this is that creeprate changes appear to start a considerable time before large and moderate-size earthquakes. This may be the case before the Loma Prieta event and especially for the 1961 quakes [see Burford, 1988; Wesson, 1988]. However, one can only specula ...
Subduction of the Chile Ridge - Geological Society of America
... Silver, 1994) is perturbed by these structures. We use observations of shear wave splitting to evaluate this issue. The most common interpretation of teleseismic shear wave splitting is based on development of a linear preferred orientation of natural upper mantle minerals, predominantly olivine, wi ...
... Silver, 1994) is perturbed by these structures. We use observations of shear wave splitting to evaluate this issue. The most common interpretation of teleseismic shear wave splitting is based on development of a linear preferred orientation of natural upper mantle minerals, predominantly olivine, wi ...
Dependence of earthquake recurrence times and independence of
... spatial region of arbitrary coordinates, shape and size, independent of tectonic divisions or provinces, only events with magnitude M larger than a threshold value Mc are selected (naturally, the value Mc has to be high enough to guarantee the completeness of the data). This means that the recurrenc ...
... spatial region of arbitrary coordinates, shape and size, independent of tectonic divisions or provinces, only events with magnitude M larger than a threshold value Mc are selected (naturally, the value Mc has to be high enough to guarantee the completeness of the data). This means that the recurrenc ...
? AN EVALUATION OF CHINESE ANNUAL
... Chinese earthquake predictions are usually made in progressive steps of long-term. medium-term, and short-term (or imminent) predictions. Typical medium-term predictions of one year are made at a 'national consultative meeting on seismic tendency' (Wu, 1997). These predictions are reported to the St ...
... Chinese earthquake predictions are usually made in progressive steps of long-term. medium-term, and short-term (or imminent) predictions. Typical medium-term predictions of one year are made at a 'national consultative meeting on seismic tendency' (Wu, 1997). These predictions are reported to the St ...
Comparison of Structural Design Actions Part 4: Earthquake Actions
... principles of seismic design and the advances in the field that lead to development of the new AS1170.4:2007 code [7] have been presented. A detailed comparison of the differences between the Layout, Notation, Factors and Calculation of the Design Base shear has been examined. The magnitude of the d ...
... principles of seismic design and the advances in the field that lead to development of the new AS1170.4:2007 code [7] have been presented. A detailed comparison of the differences between the Layout, Notation, Factors and Calculation of the Design Base shear has been examined. The magnitude of the d ...
Characterization of Fault Zones
... through-going structure at the largest available scale of a fault network that dominates the tectonic slip accommodation. The observational data, as well as modeling results, indicate that rock deformation has a relatively short initial transient phase involving strain hardening and the creation of ...
... through-going structure at the largest available scale of a fault network that dominates the tectonic slip accommodation. The observational data, as well as modeling results, indicate that rock deformation has a relatively short initial transient phase involving strain hardening and the creation of ...
Slip rates and seismic moment deficits on major active faults in
... with moment release by previous earthquakes, the deficit (unreleased moment) or surplus (over‐released moment) can provide some useful insight into the potential earthquake hazard on a given fault [Meade and Hager, 2005a]. Doing so requires a long and, ideally, a complete record of previous earthqua ...
... with moment release by previous earthquakes, the deficit (unreleased moment) or surplus (over‐released moment) can provide some useful insight into the potential earthquake hazard on a given fault [Meade and Hager, 2005a]. Doing so requires a long and, ideally, a complete record of previous earthqua ...
Juan de Fuca slab geometry and its relation to Wadati
... studies modeling similar data sets. To address this variability we developed a scheme that assigns weights to control points based on data uncertainties associated with delineating the slab location (Table S1 in the auxiliary material). Seismicity data are generally given the highest weight since we ...
... studies modeling similar data sets. To address this variability we developed a scheme that assigns weights to control points based on data uncertainties associated with delineating the slab location (Table S1 in the auxiliary material). Seismicity data are generally given the highest weight since we ...
Are earthquakes predictable? - San Andreas UCLA Seismic
... popularly defined, that is a forecast of a specific individual earthquake. Many small earthquakes occur throughout any seismic zone, demonstrating that the critical conditions for earthquake nucleation are satisfied almost everywhere. Apparently, any small shock can grow into a large event. Thus, it ...
... popularly defined, that is a forecast of a specific individual earthquake. Many small earthquakes occur throughout any seismic zone, demonstrating that the critical conditions for earthquake nucleation are satisfied almost everywhere. Apparently, any small shock can grow into a large event. Thus, it ...
The teleseismic signature of fossil subduction - Lamont
... [14] Signal S is defined on the radial component by a succession of strong positive (red) and negative (blue) pulses within the first 2 s along most of the array, with the exception of stations A16 and A17. Since the occurrence of signal S coincides with the presence of a shallow 1 km thick layer o ...
... [14] Signal S is defined on the radial component by a succession of strong positive (red) and negative (blue) pulses within the first 2 s along most of the array, with the exception of stations A16 and A17. Since the occurrence of signal S coincides with the presence of a shallow 1 km thick layer o ...
CITIES AT RISK
... These cities have physical and socioeconomic factors known to increase risk (the chance of loss) to people, buildings, and infrastructure when a M7.0 or greater earthquake occurs ...
... These cities have physical and socioeconomic factors known to increase risk (the chance of loss) to people, buildings, and infrastructure when a M7.0 or greater earthquake occurs ...
possible models of the deepest part of the larderello geothermal field
... denser terrains (Tertiary Flysch units and Triassic dolostones) than the surrounding areas (Neogene sediments), it can be inferred that this low must be of deep origin. This mass deficit, corresponding quite well to the zones with highest heat flow, would imply the presence of a low density body at ...
... denser terrains (Tertiary Flysch units and Triassic dolostones) than the surrounding areas (Neogene sediments), it can be inferred that this low must be of deep origin. This mass deficit, corresponding quite well to the zones with highest heat flow, would imply the presence of a low density body at ...
Report on the expected PGV and PGA values for
... The largest recorded induced earthquake in the Netherlands, Mw= 3.6, occurred August 16, 2012 near Huizinge in the province of Groningen at a depth of 3 km. This event caused over 3000 damage claims in the region and a re-assessment of the seismic hazard for the region was made based on recorded ind ...
... The largest recorded induced earthquake in the Netherlands, Mw= 3.6, occurred August 16, 2012 near Huizinge in the province of Groningen at a depth of 3 km. This event caused over 3000 damage claims in the region and a re-assessment of the seismic hazard for the region was made based on recorded ind ...
Seismicity and active tectonics in the Alboran Sea, Western
... high-resolution bathymetric data and seismic reflection imaging, indicating a number of small active fault zones, some of which offset the seafloor, rather than supporting a well-defined discrete plate boundary fault. Moreover, a number of large faults known to be active as evidenced from bathymetry, s ...
... high-resolution bathymetric data and seismic reflection imaging, indicating a number of small active fault zones, some of which offset the seafloor, rather than supporting a well-defined discrete plate boundary fault. Moreover, a number of large faults known to be active as evidenced from bathymetry, s ...
Seismic retrofit
Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent experiences with large earthquakes near urban centers, the need of seismic retrofitting is well acknowledged. Prior to the introduction of modern seismic codes in the late 1960s for developed countries (US, Japan etc.) and late 1970s for many other parts of the world (Turkey, China etc.), many structures were designed without adequate detailing and reinforcement for seismic protection. In view of the imminent problem, various research work has been carried out. State-of-the-art technical guidelines for seismic assessment, retrofit and rehabilitation have been published around the world - such as the ASCE-SEI 41 and the New Zealand Society for Earthquake Engineering (NZSEE)'s guidelines. These codes must be regularly updated; the 1994 Northridge earthquake brought to light the brittleness of welded steel frames, for example.The retrofit techniques outlined here are also applicable for other natural hazards such as tropical cyclones, tornadoes, and severe winds from thunderstorms. Whilst current practice of seismic retrofitting is predominantly concerned with structural improvements to reduce the seismic hazard of using the structures, it is similarly essential to reduce the hazards and losses from non-structural elements. It is also important to keep in mind that there is no such thing as an earthquake-proof structure, although seismic performance can be greatly enhanced through proper initial design or subsequent modifications.