A Performance-Based Earthquake Engineering (PBEE) assessment methodology is being used to study the impact of long-term material degradation on seismic performance of reinforced concrete bridges. The methodology, currently under development by the Pacific Earthquake Engineering Research Center, is being applied to an overpass with typical California highway details, and preliminary results are ...

The moment magnitude M 7.8 earthquake in 1906 profoundly changed the rate of seismic activity over much of northern California. The low rate of seismic activity in the San Francisco Bay region (SFBR) since 1906, relative to that of the preceding 55 yr, is often explained as a stress-shadow effect of the 1906 earthquake. However, existing elastic and visco-elastic models of stress change fail to...

although knowing the time of the occurrence of the earthquakes is vital and helpful, unfortunately it is still unpredictable. by the way there is an urgent need to find a method to foresee this catastrophic event. there are a lot of methods for forecasting the time of earthquake occurrence. another method for predicting that is to know probability density function of time interval between earth...

Twitter has become a popular microblogging service. An important characteristic of Twitter is its real-time nature. For example, when an earthquake occurs, people make many tweets related to the earthquake, which enables detection of earthquake occurrence promptly, simply by observing the tweets. In this report, we investigate the real-time interaction of events such as earthquakes, in Twitter,...

A stochastic model for earthquake occurrence focusing on the spatio-temporal interactions between earthquakes is discussed. The model is a marked point process model in which each earthquake is represented as a marked point in space and time. The marks are given by the magnitudes of the earthquakes but other observed properties of the earthquakes, such as information on the fault lines, can str...

For civil protection reasons there is a strong need to improve the inventory of areas that are more vulnerable to earthquake ground motions or to earthquake-related secondary effects, such as landslides, liquefaction or soil amplifications. The use of remote sensing and Geographic Information Systems (GIS) methods along with the related geo-databases can assist local and national authorities to...

A large number of probabilistic earthquake occurrence models are currently available for seismic hazard assessment. This paper reviews the basic assumptions of the various models, summarizes their stochastic representations and discusses the parameters needed for applications. While the Poisson model is one of the most commonly used in practice it is limited in its representation of the physica...

Spatiotemporal properties of seismicity are investigated for a worldwide (WW) catalog and for southern California in the stationary case (SC), showing a nearly universal scaling behavior. Distributions of distances between consecutive earthquakes (jumps) are magnitude independent and show two power-law regimes, separated by jump values about 200 (WW) and 15 km (SC). Distributions of waiting tim...

Like all theories in any branch of physics, theories of the seismic source should be testable (i.e., they should be formulated so that they can be objectively compared to observations and rejected if they disagree). Unfortunately, many widely held theories of the seismic source, such as the elastic rebound paradigm and characteristic earthquake model, and theories for applying them to make prob...

This paper selectively reviews physical models of earthquake instability. In these models, instability arises as a result of interaction of a fault constitutive relation with deformation of the surrounding material that occurs in response to remote tectonic loading. In contrast to kinematic models in which the fault slip is imposed, it is calculated in physical models and, consequently, these m...