The recent anniversary of Kilauea’s May 1924 explosive summit eruptions reminds us of the sometimes violent interactions that occur when relatively cool water near the Earth’s surface comes into contact with much hotter magmatic material found at depth. As chronicled in the May 8 Volcano Watch, and at several recent public presentations, even relatively small, steam-driven eruptions like those of 1924 can affect people who live on and near active volcanoes.
Long before 1924 — indeed for more than a thousand years — Hawaiians recognized the significance of magma-water interaction and depicted their understanding through oral tradition and dance. In this way, Native Hawaiians have taught that living in harmony with volcanoes such as Kilauea and Mauna Loa means respecting their power while appreciating their beauty.
“Living in harmony with volcanoes: bridging the will of nature to society” will be the theme of a Cities on Volcanoes meeting in September. An estimated half-billion people worldwide live on or near active volcanoes, and COV meetings, held about every three years, bring together scientists studying volcanic phenomena and emergency managers to exchange ideas on how to meld science and public policy in order to lessen the effects of volcanic unrest on communities worldwide.
This year’s meeting will be held in Yogyakarta, Indonesia, on the island of Java, and in the shadow of the young and restless Merapi volcano. Indonesia, with more than 60 historically active volcanoes and a population ranked fourth largest on Earth, all situated on a combined island area about the size of North Carolina, is clearly a place on the planet that’s acutely aware of what living with active volcanoes means.
When magma moves within a volcano, it makes noise, causes the ground surface shape to change, and releases gases into the atmosphere. As the “living in harmony” theme of the meeting examines societal lessons learned from dealing with volcanic crises, a robust science program will probe ways to improve volcano monitoring so as to produce improved eruption forecasts. Improving the ways volcanologists study these phenomena in real time and communicate that information is critical to providing better and timelier hazards assessments to emergency managers.
Following the weeklong meeting, there will be several field trips and specialized workshops. One of the workshops will be dedicated to studying eruptive characteristics on volcanoes that have large-scale systems, in which magma and water are continuously in close proximity. Many of these “wet volcanoes” host large crater lakes and water can be thrown out abruptly when the volcano becomes restless. When wet volcanoes erupt violently, they often produce deadly volcanic mud and debris flows, called lahars, and surges of scorching-hot rock debris. They can also produce gas or steam-driven eruptions similar to those at Kilauea in 1924.
Monitoring volcanoes with crater lakes — and Indonesia has more than 30 of them — is challenging. The interaction of water with magma produces earthquakes and tremors of different character than what is found elsewhere. Furthermore, surface deformation and gas emissions can be masked by the crater lakes sitting at the top of these volcanoes. By using enhanced geophysical and geochemical techniques to better understand processes at wet volcanoes, volcanologists will be positioned to anticipate what might happen next when wet volcanoes become restless.
The COV Wet Volcanoes Workshop will be held at Kawah Ijen crater lake in East Java and will feature a tour de force of monitoring methods designed to examine ways to improve surveillance of wet volcanoes. Automated lake level and temperature monitoring, sulfur dioxide emissions measurements using chemical sensors, spectrometers and specially designed cameras that can image gas plumes remotely, and flow-rate measurements made in streams that drain crater lakes are a few of the techniques to be tested at Kawah Ijen. And because Ijen has historically been very active, a “backup” volcano has been selected for the workshop if conditions prove inhospitable.
The COV conference, the wet volcano workshop and Kilauea’s past, present and future eruptions remind us all of the importance of living responsibly and with awareness around volcanoes.
Kilauea activity update
A lava lake within Halemaumau produced nighttime glow visible via HVO’s webcam during the past week. The lava lake level dropped during deflation that began May 10 and has remained relatively low compared to recent months, with the lava level over the past week 180 to 220 feet below the rim of the overlook crater.
On Kilauea’s east rift zone, the Kahaualea 2 flow remains active, its front 5.5 miles northeast of its vent on Puu Oo, based on mapping done Thursday. Several small spatter cones within the Puu Oo crater continue to produce glow.
There was one earthquake reported felt in the past week on Hawaii Island. At 6:25 a.m. Wednesday, a magnitude 2.5 earthquake occurred 7 miles south of Hawi at a depth of 16 miles.
Visit the HVO website, hvo.wr.usgs.gov, for Kilauea, Mauna Loa and Hualalai activity updates, volcano photos and recent earthquakes; 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.
