Earlier this year, the Alaska Volcano Observatory completed its first 25 years of operation. It received widespread acknowledgement for its crucial role in warning of eruptions and advancing scientific understanding of the hazards posed by Alaskan volcanoes. Earlier this year,
Earlier this year, the Alaska Volcano Observatory completed its first 25 years of operation. It received widespread acknowledgement for its crucial role in warning of eruptions and advancing scientific understanding of the hazards posed by Alaskan volcanoes.
It was an immensely ambitious and challenging 25 years, marked by more than 70 different episodes of eruption and unrest from nearly 30 different volcanoes and the most expansive volcano-monitoring effort in U.S. history.
The signature event that shaped the observatory’s mission more than any other was the 1989-90 eruption of Redoubt Volcano, located 110 miles southwest of Anchorage. One of the eruption’s ash clouds nearly brought down a Boeing 747 jetliner carrying 244 people as it descended into Anchorage.
The plane flew through an ash cloud erupted by the volcano and quickly lost power to all four engines. After a steep and terrifying descent to within 4,000 feet of the ground, the pilots were able to restart the engines and land safely.
This encounter between ash and aircraft soon galvanized support for an aggressive effort to scale-up monitoring of Alaska’s historically active and potentially active volcanoes by increasing the number of ground-based instruments and the use of satellite resources.
AVO increased the number of Alaskan volcanoes monitored with seismic instruments from 4 in 1995 to 29 in early 2013, a remarkable feat, given the notorious weather in Alaska and the great length of the volcanic chain that stretches from Cook Inlet to the Aleutian Islands — more than 1,500 miles.
Support for AVO was also focused on developing capability and expertise to use satellite resources to detect signs of unrest; identify and track ash clouds downwind from an erupting volcano; and advance computer models used to forecast the downwind path of ash.
With so many active and erupting volcanoes to monitor, AVO constantly strove to improve and rapidly disseminate volcano activity notifications and ash-cloud information to the aviation industry and to the public in collaboration with the Federal Aviation Authority and National Weather Service.
During the 1989-90 Redoubt eruption, AVO implemented a novel four-level color scheme for communicating the immediate status or hazard level of the volcano in a simple, consistent manner. Green, for example, meant the volcano was quiet. Yellow was for slightly elevated activity but no eruption. Orange and red represented eruptions that generated ash columns to increasing altitudes.
The color scheme was eventually endorsed by the International Civil Aviation Organization for use by volcano observatories worldwide. It served as the basis for the new, standardized alert-notification systems used by all U.S. volcano observatories beginning in 2006 — see pubs.usgs.gov/fs/2006/3139/fs2006-3139.pdf.
The standardized alert system enabled the creation of the Volcano Notification Service that sends emails to subscribers about volcanic activity at monitored U.S. volcanoes. Subscribers can customize requests to receive notifications only for certain volcanoes, or range of volcanoes, or by notification type — to subscribe, visit volcanoes.usgs.gov/vns. Nearly 4,500 people have subscribed since the program was publicly launched in 2012.
This year, AVO launched “Is Ash Falling?” — a Web tool to help improve the collection of ash-fall information in near real-time. The online form allows people to report on the timing and location of ash fall and the thickness of the resulting deposit. Users of the AVO website, avo.alaska.edu, are directed to the form on the activity page of an erupting or restless volcano, where they can also view a map of ash-fall reports.
These firsthand accounts of ash-fall information help scientists better identify the path of developing ash clouds, quantify ash deposition, and improve warning messages about ash. The accounts are “ground-truthing” crucial for continually improving interpretation of satellite imagery and new computer models used to forecast when and where ash will go and what areas it will affect.
Soon after its 25th anniversary in April, eruptions of two of Alaska’s most active volcanoes — Pavlof and Veniaminof — generated small eruptions and ash clouds. Volcano monitoring requires the vigilance of AVO, and now more than ever, the public.
Kilauea activity update
A lava lake within the Halemaumau overlook vent produced nighttime glow visible via HVO’s webcam during the past week. Two deflation-inflation cycles occurred during the week, as of Thursday, and the lava lake level fell, then correspondingly rose again during each cycle.
On Kilauea’s east rift zone, a breakout from the Peace Day tube above the pali was probably still active Tuesday, based on infrared satellite imagery. The Kahaualea 2 flow, fed from a spatter cone on the northeast edge of the Puu Oo crater, continues to advance slowly across old flows and into the forest. Its tip was 3.6 miles northeast of Puu Oo when last mapped Oct. 21.
No earthquakes were reported felt on Hawaii Island during the past week.
Visit hvo.wr.usgs.gov for Kilauea, Mauna Loa and Hualalai activity updates, recent volcano photos, recent earthquakes and more; call 967-8862 for a Kilauea summary; email questions to askHVO@usgs.gov.
Volcano Watch is a weekly article and activity update written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.
