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.
Vents in the surface of the Earth through which magma and associated gases erupt; also, the forms or structures, usually conical, that are produced by the erupted material. [Glossary of Geology, 4th ed.]
Homepage for USGS Volcano Hazards Program with feature stories, and links to worldwide volcano updates, volcanic hazards, reducing volcanic risk, USGS international programs, and resources such as educator's page, videos, and online reports.
Homepage for Alaska Volcano Observatory (AVO) with offices in Anchorage and Fairbanks monitors and studies Alaska's hazardous volcanoes. Links to featured news, updates, publications and products, and a volcano atlas for Alaska.
Portal to information provided by the Cascades Volcano Observatory in Vancouver, WA with links to reports and activity in the Cascade Range and other volcanoes and multiple links to general information on volcanology, reports, research, and maps.
Describes the monitoring effort and provides real-time data of the current restless activity of the caldera, including earthquakes, ground deformation, and release of volcanic gas and plus link to volcano monitoring techniques.
Overview of volcano hazards in California with links to monitoring data including earthquakes and deformations, long-term outlook, volcano hazards in the area, USGS response plan, image gallery, monitoring and topical studies, publications and references.