Large deep-focus earthquakes (magnitude> 7.0, depth> 500 km) have exhibited strong seasonality in their occurrence times since the beginning of global earthquake catalogs. Of 60 such events from 1900 to the present, 42 have occurred in the middle half of each year. The seasonality appears strongest in the northwest Pacific subduction zones and weakest in the Tonga region. Taken at face value, t...

[1] In 2003, Ekström et al. reported the detection and location of a new class of earthquakes occurring in the polar regions of the Earth. The proposed source mechanism involves large and sudden sliding motions of glaciers, which gave the name ‘‘glacial earthquakes’’ to these events. In this study we localize some of these earthquakes with a time reversal mirror (TRM) algorithm, which, contrary...

Rapid procedures (i.e. within 5 to 15 minutes) for earthquake and tsunami early warnings focus on earthquake location, depth, magnitude, and slowness, but initial tsunami early warnings are more often issued without knowing the mechanism of the earthquake. Kawakatsu (1998) proposed using a limited number of stations to automatically detect, locate and determine the source parameters of earthqua...

The offshore Castor Underground Gas Storage (UGS) project had to be halted after gas injection triggered three M4 earthquakes, each larger than any ever induced by UGS. mechanisms that seismicity in the crystalline basement at 5–10 km depth 1.7 remain unknown. Here, we propose a combination of explain observed seismicity. First, critically stressed Amposta fault, bounding storage formation, cre...

This paper inspects possible influence of solar cycles on earthquakes through of statistical analyses. We also discussed the mechanism that would drive the occurrence of increasing of earthquakes during solar maxima. The study was based on worldwide earthquakes events during approximately four hundred years (16002010).The increase of earthquakes events followed the Maxima of Solar cycle, and al...

Earthquakes are one of the most destructive natural phenomena which consist of rapid vibrations of rock near the earth’s surface. Because of their unpredictable occurrence and enormous capacity of destruction, they have brought fear to mankind since ancient times. Usually the earthquake acceleration is noted from the equipment in crisp or exact form. But in actual practice those data may not be...

In this research, we use high frequency waveform information to determine the focal mechanisms of small local earthquakes at an oil reservoir. During the waveform inversion, we maximize both the phase and amplitude matching between the observed and synthetic waveforms. In addition, we use the polarities of the first P-wave arrivals and the S/P amplitude ratios to better constrain the matching b...

The devastating effects of earthquakes have been demonstrated repeatedly in the past decade, through moderate and major earthquakes such as the October 1987 Whittier Narrows earthquake (5.9 on the Richter scale), the October 1989 Loma Prieta earthquake (7.1) and the January 1994 Northridge earthquake (6.7). While 'official' tallies of injuries and deaths are reported for each event, the numbers...

O 31 October 2008 and the following day, numerous Dallas-Fort Worth (DFW) residents called 911 to report experiencing several small earthquakes, accompanied by loud booming noises and the shaking of walls and furniture. Using data recorded by regional seismic stations, the USGS National Earthquake Information Center (NEIC) located nine earthquakes with magnitudes between 2.5 and 3.0. On 16 May ...

moment-resisting frames have extensive usage in earthquake-prone areas and high ability in energy dissipation.after the earthquake in northridge 1994,kobe 1995 fixed connections of steel structures have shown poor performance and generally they were caught brittle fracture of beam flange weld to the column.in order to remedy to avoid similar situations in future earthquakes,researchers introduc...