AVO has three primary objectives:

• To conduct monitoring and other scientific investigations in order to assess the nature, timing, and likelihood of volcanic activity;
• To assess volcanic hazards associated with anticipated activity, including kinds of events, their effects, and areas at risk; and
• To provide timely and accurate information on volcanic hazards, and warnings of impending dangerous activity, to local, state, and federal officials and the public.

AVO offices are in Anchorage and Fairbanks, Alaska. The Anchorage office is at the USGS, and is the primary point of information dissemination during crises. Fairbanks offices are concentrated at the UAFGI, which serves as the data collection point for most of the seismic and satellite data. AVO is staffed by the equivalent of about 22 full-time scientists, technicians, and administrators. Managerial responsibility for AVO rests with the Scientist-in-Charge, a USGS employee in Anchorage, and the Coordinating Scientist in Fairbanks, a UAFGI or ADGGS employee.

In support of public land-use planning, development of emergency response plans, and general public awareness of the nature of volcanic activity in Alaska, AVO is responsible for assessing the full range of potential hazards at specific volcanic centers. This effort involves studying a volcano to determine the style and frequency of past eruptions, and potential impacts of future activity. Hazards assessments include descriptions of the history of a given volcano, explanations of likely eruption scenarios, and determination of probable impact zones for the range of expected hazards. Ultimately, hazards assessments will be published for all seismically monitored volcanoes. Those which have been completed to date are available as PDF files in the "library" section of this site.

Alaska's active volcanoes offer superb opportunities for basic scientific investigations of volcanic processes. An important component of AVO's program is to conduct research at selected volcanic centers. The scope of this research includes:

• Basic geological mapping to determine eruptive histories of active volcanoes,
• Geochemical characterization and modeling of diverse magmatic systems,
• Investigations of hydrologic hazards associated with eruptions of snow and ice-clad volcanoes,
• Documentation and analysis of eruptive processes,
• Geophysical exploration of the interiors of volcanoes and mechanisms of eruption, and
• Development of new instrumentation to aid in prediction and interpretation of volcanic unrest.

Results of these studies contribute significantly to accurate completion of volcanic hazards assessments and to the continual improvement AVO's monitoring and predictive capabilities.

The backbone of AVO's volcano monitoring program consists of networks of continuously recording seismometers installed at selected volcanoes. Seismic data are relayed to AVO facilities in Fairbanks and Anchorage where they are analyzed both automatically and by analysts. Initially, AVO concentrated its monitoring efforts on the four Cook Inlet volcanoes because they are closest to Alaska population centers. In response to the increasing hazard to aviation from volcanic ash, AVO started a program of expansion in 1996 to other volcanoes in the Aleutian Islands and on the Alaska Peninsula, and now monitors more than 20 volcanoes. Volcanic unrest, caused by the migration of magma and other fluids through the earth's crust, is heralded by increased seismicity, often months to weeks before eruption. Because the seismometers provide a continuous data stream the onset of explosive eruptions can be detected quickly in most cases and appropriate warnings issued. An electronic alarm system is employed during non-business hours.

Satellite imagery provides information which complements seismic monitoring at those volcanoes with seismic networks, and is the only source of routine monitoring information at those without. AVO analyzes available satellite data twice daily for thermal anomalies and ash plumes at about 80 volcanoes in the north Pacific. Thermal anomalies at volcanic vents have been detected up to several weeks before large eruptions. Volcanic ash erupted into the atmosphere is a serious hazard to jet aircraft because it can cause their engines to shut down as it is ingested. By analyzing satellite imagery and working with the National Weather Service to predict where winds will carry the ash, AVO assists the Federal Aviation Administration in warning aircraft of areas to avoid.

Space-based deformation monitoring is an emerging technique. AVO operates a network of telemetered GPS receivers at Augustine Volcano, in lower Cook Inlet that provide a continuous record of ground deformation. AVO also conducts periodic field-based GPS surveys as well as measuring deformation with satellite radar interferometry (InSAR) techniques. These techniques are providing important information about inflation and deflation of volcanoes, but are not yet evolved enough for routine real-time monitoring of many volcanoes.