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 Earth’s surface comes into contact with much hotter magmatic material found at depth.
As chronicled in the May 8 Volcano Watch (http://hvo.wr.usgs.gov/volcanowatch), and at several recent public presentations, even relatively small, steam-driven eruptions such as 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, during many generations, that living in harmony with volcanoes like 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 featured theme at the upcoming Cities on Volcanoes (COV) meeting in September. An estimated half-billion people worldwide live on or near active volcanoes, and COV meetings, hosted about every three years, bring together scientists studying volcanic phenomena and emergency managers to exchange ideas about how to meld science and public policy to lessen the effects of volcanic unrest on communities worldwide.
This year’s meeting will be 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 acutely aware — on a daily basis — 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 to 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 hazard assessments to emergency managers.
Following the week-long 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 so-called “wet volcanoes” host large crater lakes whose 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. But by using specially chosen and 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 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, there’s even a “backup” volcano that will be shifted to if conditions there prove too inhospitable.
The Cities on Volcanoes conference, the Wet Volcanoes Workshop within it, and, more locally, Kilauea’s past, present and future eruptions all remind us of the importance of living responsibly and with awareness around volcanoes.
Kilauea activity update
A lava lake within Halema‘uma‘u 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 lava level during the past week 55-68 meters (180-220 feet) below the rim of the Overlook Crater.
On Kilauea East Rift Zone, the Kahauale‘a 2 flow remains active, its front 8.8 kilometers (5.5 miles) northeast of its vent on Pu‘u ‘O‘o, based on mapping May 22. Several small spatter cones within the Pu‘u ‘O‘o crater continue to produce glow.
There was one earthquake reported felt in the past week on the Island of Hawaii. At 6:25 a.m. May 21, a magnitude 2.5 earthquake occurred 11 kilometers (7 miles) south of Hawi at a depth of 25 kilometers (16 miles).
Visit the HVO website (http://hvo.wr.usgs.gov) for Kiauea, 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 (http://hvo.wr.usgs.gov/volcanowatch/) is a weekly article and activity update written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.