Volcano Watch: How does HVO determine which regions are most threatened by lava flows?

Most residents of the Island of Hawaii live on one of four potentially active volcanoes and probably have wondered about the threat of lava flows at one time or another. Interestingly, determining future threats relies on knowledge of the past. The long-term likelihood of an area being invaded by lava in the future, is estimated in two different ways based on the history of lava flow activity.

Volcano Watch: The MILEAGE project — mapping Kilauea’s gas emissions

Large quantities of volcanic gases, such as carbon dioxide (CO2), sulfur dioxide (SO2), and hydrogen sulfide (H2S), are released into the atmosphere during volcanic eruptions. But even between eruptions, smaller amounts of the same gases continue to escape and can provide important clues about the current state of the volcano and the underlying magma. But to measure them, you first must identify where gas is coming from.

Volcano Watch: Eruption? Intrusion? What’s the difference?

We know that when a volcano erupts, molten red rock makes it to the surface, while during an intrusion it doesn’t. The difference between the two processes, if we depend on seismicity (earth shaking) or deformation (changes in ground surface) instrumentation, is not obvious. The events during the start of either are identical. But we can’t be certain that an intrusion will lead to an eruption.

Volcano Watch: New Kilauea summit intrusion draws comparison to past activity

Late Monday afternoon, earthquake activity picked up at Kilauea’s summit. At about 1:30 a.m. HST on Tuesday, that activity intensified, and it became clear that seismicity and increasing deformation were indicating a new intrusion of magma. The seismicity extended southward from Halema‘uma‘u crater, to an area south of the Kilauea caldera.

Kilauea alert level raised after series of earthquakes

The Hawaiian Volcano Observatory raised its alert level for Kilauea from “advisory” to “watch” Tuesday morning after an ongoing series of small earthquakes was detected beneath Hawaii Volcanoes National Park.

Volcano Watch: ‘Aila‘au — the largest subaerial Kilauea lava flow

Kilauea volcano alternates between periods dominated by lava flows, such as the one we are currently in, and periods of explosive activity. About 1,000 years ago, effusive eruptions broke a 1,200-year period of predominantly explosive activity. During this time, lava flows accumulated on the floor of the Powers caldera — the predecessor of the present-day caldera at Kilauea summit. Eventually, lava filled and started to overflow the caldera, forming two large shields where the caldera had been.

Volcano Watch: 1790 was a bad year at Kilauea

The deaths apparently occurred along a trail crossing the northwest flank of Kilauea near Namakanipaio, when a ground-hugging surge of hot steam and rocks swept across the ground at high speed. Wet volcanic ash fell just before the lethal surge, and several hundred people left footprints in the ash beyond the limit of the surge.

Volcano Watch: A spaceborne sentinel keeps watch over Hawaiian volcanoes

Geologists at the USGS Hawaiian Volcano Observatory (HVO) had their mobile phones buzzing this past week with automated alert messages, notifying them that there was something new and hot on the Island of Hawaii. Although the internal alert system is meant to detect new volcanic activity, no eruption was occurring.

Volcano Watch: Learning from the 1984 eruption of Mauna Loa

Inflation and earthquake activity ramped up prior to Mauna Loa’s 1984 eruption, so much so that in June of 1983, the USGS Hawaiian Volcano Observatory (HVO) indicated that an eruption could occur during the following year, though the exact timing was unknown.

Remembering Mauna Loa’s 1975 eruption

Mauna Loa erupted 46 years ago this week, on July 5 and 6, 1975, in a 20-hour event with vents confined to the summit region (the area above 12,000 feet) and lava flows descending to just below 10,400 feet. This was the first eruption in 25 years, at the time the longest quiet stretch since 1843 (we are currently in the longest stretch at 37 years and counting).

Volcano Watch — Volcanoes in Canada, eh?

Happy Canada Day/Bonne Fête du Canada! While some past “Volcano Watch” articles have had a July 4 theme for the USA, this year we’re taking the opportunity to ensure readers know that our neighbors to the north have volcanoes, too—including potentially active ones.

Volcano Watch: New instrument measures lava lake with laser

Eyewitnesses drawn to the crater rim were excited, reverent, and watchful. The eruption onset was observed near and far via technology. The USGS Hawaiian Volcano Observatory (HVO) was onsite and online, transmitting scientific information as the eruption response mounted.

Earthquake at Lo‘ihi rattles Big Island

A magnitude-4.0 earthquake that struck Wednesday evening below the Lo‘ihi seamount appears to have had no impact on Kilauea or Mauna Loa volcanoes, the USGS said.