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The MELT area between 15 [degrees] to 19 [degrees] S (17) shows a pronounced asymmetry across the East Pacific Rise (EPR) in several characteristics such as spreading rate (faster to […]

Analysis of seismograph network data, earthquake catalogs from 1727 to 1982, and paleoseismic data for the central and eastern United States indicate that the Poisson probability of a damaging earthquake [...]

Nonuniformity in the upwelling region corresponding to a reasonable expanding center velocity structure leads to the occurrence of near-axis travel time advance at an array of seismographs arranged across the axis of the southern mid-Atlantic Ridge as represented by the seismic model. Shear-induced argument of anisotropic components in the upwelling mantle enhances seismic velocity of rays directed through the upwelling zone in a subvertical direction. The travel-time progress of P-waves from far-reaching earthquake stations near the axis is less than that of corresponding P-waves travelling toward stations far from the axis.

An overview is presented on the history and contributions of seismological research, focusing on the National Earthquake Hazards Reduction Program launched in 1977. The Alaskan earthquake of 1964 and California's San Fernando earthquake of 1971 emphasized the need for a nationally unified approach to research and mitigation.

Irregular Recurrence of Large Earthquakes Along the San Andres Fault: Evidence from Trees LARGE EARTHQUAKES OCCUR ALONG the San Andreas fault northeast of Los Angeles about very 131 years (1-4). [...]

Seismologists don't fully understand a controversial Greek prediction scheme, and some think its 'successes' are just luck. But it is enticing many researchers Each time researchers have flirted with a [...]

Astronomers, whose gaze has been drawn to the twinkling points of light that are stars, would dearly love a peek into their interiors. Such a vision, for example, might allow [...]

A boundary between compositionally distinct regions at a depth of about 1600 kilometers may explain the seismological observations pertaining to Earth's lower mantle, produce the isotopic signatures of mid-ocean ridge basalts and oceanic island basalts, and reconcile the discrepancy between the observed heat flux and the heat production of the mid-ocean ridge basalt source region. Numerical models of thermochemical convection imply that a layer of material that is intrinsically about 4 percent more dense than the overlying mantle is dynamically stable. Because the deep layer is hot, its net density is only slightly greater than adiabatic and its surface develops substantial topography., Several fundamental constraints must be satisfied by a successful model of the dynamics and thermochemical structure of Earth's mantle. The model must produce sufficient heat, either by radioactive decay or [...]

SAN FRANCISCO--Topics ranging from the atmosphere to the inner Earth were served up at the annual fail meeting of the American Geophysical Union here Last month. Below, we report two [...]

Experimentalists have taken another step toward solving the central mystery of deep earthquakes: How can rock break at all at a depth of hundreds of kilometers? At those depths the [...]