Gathering information through periodic or continuous measurement in the field to provide a view of current conditions. In some instances, observations may not be subject to rigorous review before release; this will be noted in the documentation accompanying the data.
Information on world earthquake activity with links to facts and lists on large earthquakes, earthquake e-mail notification, hazards and preparedness, educational links, news and highlights and other seismic information.
Overview of USGS programs related to geomagnetism including observatories, data, program services, links to models, charts, and movies, program contacts, Intermagnet, Geomag, publications, and bibliographies.
NWISWeb homepage for the National Water Information System providing access to water-resources data collected at approximately 1.5 million sites in all 50 States, the District of Columbia, and Puerto Rico.
Description of seismograms and how they are produced by drum recorders and electronic instruments with real-time seismograms for Northern California and Long Valley, California and representative seismograms for types of earthquake activity.