************************************************* ALASKA VOLCANO OBSERVATORY Information Release Thursday, May 3, 2007 3:15 PM AKDT (2315 UTC) ************************************************* FOURPEAKED VOLCANO (CAVW#1102-26-) 58 46'9" N 153 40'26" W, Summit Elevation 6903 ft (2104 m) Current Aviation Color Code: YELLOW Current Volcanic Activity Alert Level: Advisory AVO is adding Fourpeaked Volcano to its list of seismically monitored Alaskan volcanoes. On September 17, 2006 two steam plumes were observed rising from Fourpeaked to an altitude of about 6,000 m above sea level (20,000 feet). Subsequent gas measurements showed a significant amount of SO2 coming from the volcano. Following these events, AVO installed a monitoring network on Fourpeaked, consisting of three new short-period seismometers, two co-located pressure sensors, one pre-existing short-period seismometer at Cape Douglas, and a web camera. The network has operated successfully through the winter and has recorded 380 locatable earthquakes. Pressure sensors have recorded pressure transients that may represent small explosions near the volcano's summit. The addition of Fourpeaked Volcano brings the total of seismically monitored volcanoes to 31. Fourpeaked Volcano lies within the northeast corner of Katmai National Park and Preserve on the Alaska Peninsula, 7.5 miles (12 km) southwest of Mount Douglas. It is a stratovolcano that is mostly covered by Fourpeaked Glacier. Small isolated volcanic exposures along ridge crests and cliff faces radiate out from the ice-covered summit. The last major eruption at Fourpeaked was probably more than 10,000 years ago. If there have been eruptions within the last 10,000 years, they were small enough that they did not leave recognizable deposits. There is no record of eruptions within the past few hundred years. Local residents report that steaming similar to the current activity may have occurred several decades ago. VOLCANIC-ALERT LEVELS (contact AVO for complete description): NORMAL Typical background activity of a volcano in a non-eruptive state ADVISORY Elevated unrest above known background activity WATCH Volcano is exhibiting heightened or escalating unrest with increased potential for eruptive activity WARNING Highly hazardous eruption underway or imminent ABBREVIATED AVIATION COLOR CODE KEY (contact AVO for complete description): GREEN volcano is dormant; normal seismicity and fumarolic activity occurring YELLOW volcano is restless; eruption may occur ORANGE volcano is in eruption or eruption may occur at any time RED significant eruption is occurring or explosive eruption expected at any time VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu RECORDING ON THE STATUS OF ALASKA\'S VOLCANOES (907) 786-7478 CONTACT INFORMATION: Tom Murray, Scientist-in-Charge, USGS tlmurray@xxxxxxxx (907) 786-7497 Steve McNutt, Coordinating Scientist, UAF steve@xxxxxxxxxxxxxxxxx (907) 474-7131 The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys. ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
