Volcano Watch — Priority of volcano-monitoring improvements based on threat and current activity

Release Date:

A new report released two weeks ago by U.S. Geological Survey scientists evaluated 169 volcanoes in the United States that could erupt again and pose a threat to people, property, and commercial aircraft. It recommended different levels of volcano monitoring systems to match the widespread but varying threat.

According to the report, the highest priority for new and expanded volcano-monitoring systems should be given to the most dangerous volcanoes and to those volcanoes currently erupting or showing signs of reawakening.

In Hawai`i, this would include Kīlauea, erupting since 1983, Mauna Loa, which has been restless for the past 3 years, and Hualālai volcanoes.

Last week we described the way in which U.S. volcanoes were assigned a threat ranking based on 15 hazard factors (range of activity and effects in the recent past) and 10 exposure factors (what could be affected by eruption). The volcanoes were then divided into 5 groups ranging from Very Low Threat to Very High Threat.

Kīlauea (1st) and Mauna Loa (8th) volcanoes ranked in the Very High Threat group. Sixteen other volcanoes are in this group, including Mount St. Helens (2nd) and Mount Rainier (3rd) in Washington; Mount Hood (4th) in Oregon; and Mount Shasta (5th) and Lassen Peak (7th) in northern California. In Alaska, 3 volcanoes surrounding Cook Inlet made it into the top threat list--Redoubt (9th), Mount Spurr (15th), and Augustine (18th).

Hualālai (30th) is in the High Threat group, while Haleakalā (83rd) on Maui and Mauna Kea (97th) are in the Moderate Threat group.

This week we focus on two main questions: (1) for each of the 169 volcanoes, does the current level of monitoring, if any, match the level warranted by potential threat posed by the volcano? (2) If it does not, what improvements are needed?

The current national monitoring strategy largely depends on waiting to install a volcano-monitoring network until signs of restless activity are obvious-current Federal funding levels do not support any other approach.

When a volcano that is not well monitored becomes restless, scientists are forced to "play catch-up" with a volcano to purchase, build, and install networks and provide up-to-date assessments of the volcano. Time and data can be lost in the weeks it may take to establish an adequate monitoring network-precious time and data that public officials and the public needs to prepare for potential volcanic activity.

The authors evaluated both the current status and recommended volcano-monitoring capabilities by describing 5 monitoring levels. Each level includes a different suite and detail of instruments and monitoring methods.

For example, level 4 indicates a well monitored volcano such that the volcano's activity can be thoroughly tracked in real time by nearly all established techniques for developing, testing, and applying models for what the volcano is doing or about to do.

Level 1 indicates minimal monitoring that should provide scientists with the ability to detect an eruption or determine that large changes are occurring near a volcano. This level might consist of a single seismometer within about 10 km (6 miles) of a volcano to detect earthquakes. Level 0 indicates no monitoring at all.

The authors then recommended that the Very High Threat and High Threat Volcanoes have level-4 monitoring capability and that Moderate Threat Volcanoes have a level 3.

So how did Hawai`i's volcanoes rank in monitoring capability and improvements needed?

For Kīlauea and Mauna Loa volcanoes, the best-monitored in Hawai`i, a level-4 monitoring capability was recommended, the level currently in place.

For Hualālai, a level-4 monitoring was recommended but it only has level-2 monitoring, leaving a "monitoring gap" of 2.

Haleakalā and Mauna Kea should both have level-3 capability but are monitored only at level 2, leaving a gap of 1.

The overall rankings in the report are intended to help guide and prioritize the future expansion of U.S. volcano-monitoring capabilities in order to improve the ability of scientists to provide early warnings of volcanic activity. Achieving and maintaining the right level of monitoring for Hawaii's volcanoes has always been a high priority for the Hawaiian Volcano Observatory.

The full report can be found at: http://pubs.usgs.gov/of/2005/1164/


Volcano Activity Update

Eruptive activity at Pu`u `O`o continues. On clear nights, glow is visible from several vents within the crater and on the southwest side of the cone.

The PKK lava tube continues to produce intermittent surface flows from above the top of Pulama pali to the ocean. Lava is currently entering the ocean at both East Lae`apuki and Kamoamoa, and surface flows are active intermittently inland of the entries. The East Lae`apuki entry is the closest activity to the end of Chain of Craters Road, in Hawai`i Volcanoes National Park, and is located about 4.5 km (3 miles) from the ranger shed. Expect a 2-hour walk each way and bring lots of water. Stay well back from the sea cliff, regardless of whether there is an active ocean entry or not. Heed the National Park warning signs.

During the week ending May 11, there were no earthquakes reported felt on Hawai`i Island.

Mauna Loa is not erupting. During the week ending May 12, 9 earthquakes were recorded beneath the summit area. Five were deep and long-period in nature. Inflation has slowed beneath the summit and flanks over the last few weeks.