Temporal analyses were completed between the occurrence of intense displays of exotic luminous phenomena over a church in Zeitoun (Egypt) during the years 1968 through 1969 and regional seismicity. These phenomena, viewed by thousands of onlookers, began one year before an unprecedented increase (factor of 10) in seismic activity about 400 km to the southeast. Monthly analyses also demonstrated...

A Linked stress release model, incorporating stress transfer and spatial interaction between diierent seismic regions, is proposed. The model is applied to spatio-temporal seismicity analysis of historical earthquake catalogues and synthetic ones generated by physical models. The results highlight the triggering mechanism of earthquake occurrence and the evidence that the crust may lie in a nea...

The systematic testing of intermediate-term earthquake prediction algorithms is faced with the difficulties of (1) the limited time spanned by instrumental catalogs of seismicity in most areas of the world, and (2) the relative arbitrariness of the selection of the region and time interval over which to apply the algorithm. We offer a systematic method which uses worldwide seismicity to compute...

A high-resolution relative earthquake location procedure is used to image the fine-scale seismicity structure of the northern Hayward fault, California. The seismicity defines a narrow, near-vertical fault zone containing horizontal alignments of hypocenters extending along the fault zone. The lineations persist over the 15-year observation interval, implying the localization of conditions on t...

S U M M A R Y In 2005 August, an unusual series of 47 earthquakes occurred over a 12-hr period in central Switzerland. The earthquakes occurred at the end of 3-d period of intensive rainfall, with over 300 mm of precipitation. The highest seismicity occurred as two distinct clusters in the region of Muotatal and Riemenstalden, Switzerland, a well-known Karst area that received a particularly la...

Iran is well known for having countless historical and instrumental records of tectonic events. Shahriary catchment, as a study area, is part of the Zagros collision seismic province. This research aimed to introduce a new method which is useful in identifying the relative active tectonic events of an area. The research method was designed in order to calculate the relative active tectonic inde...

The reservoir-induced seismicity (RIS) at the Karkheh dam site with a reservoir capacity of about 7.4x109 meters is investigated. Based on the assessment of the seismicity of the dam site in equal time periods before and after reservoir impoundment, it was found that the number of earthquakes have been tripled after impoundment, while their magnitudes and focal depths become smaller. The averag...

The observation of foreshocks preceding large earthquakes and the suggestion that foreshocks have specific properties that may be used to distinguish them from other earthquakes have raised the hope that large earthquakes may be predictable. Among proposed anomalous properties are the larger proportion than normal of large versus small foreshocks, the power law acceleration of seismicity rate a...

S U M M A R Y A high-quality data set of 3790 earthquakes were simultaneously inverted for hypocentre locations and 3-D P-wave velocities in Costa Rica. Tests with synthetic data and resolution estimates derived from the resolution matrix indicate that the velocity model is well constrained in central Costa Rica to a depth of 70 km; northwestern and southeastern Costa Rica are less well resolve...

S U M M A R Y Motivated by a recent resurgence in earthquake predictability research, we present a method for testing alarm-based earthquake predictions. The testing method is based on the Molchan diagram—a plot of miss rate and fraction of space–time occupied by alarm—and is applicable to a wide class of predictions, including probabilistic earthquake forecasts varying in space, time, and magn...