Earth Science

Hydrothermal processes at mid-ocean ridges, Susan E. Humphris, Dept. of Geology & Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts. Introduction. Distribution and Temporal Variability of Submarine Hydrothermal Systems. East Pacific Rise at 9-10 N. Juan de Fuca Ridge. Mid-Atlantic Ridge. Working Models Relating Hydrothermalism to Volcanic and Tectonic Activity. Rock-Water Interactions in the Oceanic Crust. Evolution of Permeability and its Relation to Off-Axis Hydrothermal Circulation. Outstanding Problems and Future Directions. References.
U.S. National Report to IUGG, 1991-1994, Rev. Geophys. Vol. 33 Suppl., 1995 American Geophysical Union.

A nonprofit organization working toward global earthquake safety.

The mission of the Environmental Protection Agency is to protect human health and the environment. Since 1970, EPA has been working for a cleaner, healthier environment for the American people. View the Agency's complete strategic plan, annual report, and policy resources.

GRACE is a joint project between the National Aeronautics and Space Administration (NASA) and the Deutsches Zentrum fr Luft- und Raumfahrt (DLR). The primary Science Objective of the GRACE mission is to provide with unprecedented accuracy, global and high-resolution estimates of the constant and time-variable part of the Earth's gravity field. Secondary objective is the measurement of several hundred globally distributed profiles per day of the excess delay or bending angle of GPS measurements caused by the atmosphere and ionosphere, which can be converted to total electron content and/or refractivity, respectively.

he twin GRACE satellites, launched March 17, 2002, are designed to produce a new model of the Earth's gravity field with unprecedented accuracy. The estimates of the time variations in the gravity field obtained from GRACE, in conjunction with other satellite and in-situ data, and geophysical models, can provide improved measurements of deep ocean currents, ocean bottom pressure, sea level rise, sea ice mass variation and distribution, soil moisture, groundwater transport, and land density.

Earthquake activity. Current earthquakes in the USA and the world. ShakeMaps. Seismogram displays. Past and historical earthquakes.

Welcome to the U.S. Geological Survey Earthquake Hazards Program Website. Information on worldwide earthquake activity, earthquake science, and earthquake hazard reduction. List of latest worldwide earthquakesMaps of recent earthquake activity. Earthquake news and highlights.

The goal of San Andreas Fault Observatory at Depth (SAFOD) is to provide direct observational data on the composition, physical state and mechanical behavior of the San Andreas fault zone at depth to test hypotheses pertaining to faulting and earthquake generation.

Ridge 2000 is an interdisciplinary initiative funded by the U.S. National Science Foundation to study the Earth's oceanic spreading ridge system as an integrated whole, from its inception in the mantle to its manifestations in the biosphere and water column.

Designed to understand the complex interplay of processes that govern the evolution of continental margins from continental rift margins to subduction zones.