USGS: To help us understand what could happen at Kīlauea Volcano’s summit, we look to past similar events, but this does not mean that future events will be exactly the same. This map shows the distribution of ballistics and tephra from the 1924 phreatic (steam-driven) explosions. Ballistics (blocks of rock) greater than 10 inches in size, with some weighing up to several tons, landed in the shaded pink area. Marble- to pea-sized rocks (about 0.2–10 inches in size) landed in the yellow shaded area. The surrounding light-colored area was subjected to gritty to fine ashfall, with fallout locations influenced by wind direction at the time of the explosions.

(BIVN) – On Friday afternoon, Hawai‘i County Civil Defense issued the first message about a possible explosive eruption at Halemaʻumaʻu.

Last night, Hawai‘i Volcanoes National Park closed until further notice

Here is the full text of message:

The Hawaiian Volcano Observatory has cautioned about the possibility of an explosive eruption at Halemaʻumaʻu.

This is caused by the withdrawal of lava from Halemaʻumaʻu’s summit lake, which leads to a steam-driven eruption. Such an eruption could generate ash plumes as high as 20,000 feet. The area affected by ash plumes could be as wide as 12 miles.

Should this occur, the following are advised:

The danger from this eruption is ash fallout. The major response is to protect yourself from fallout.

If this event occurs while you are at home, stay indoors with the windows closed. Turn on your radio and listen for updates from authorities.

If you are in your car, keep the windows closed. Ash fallout may cause poor driving conditions, due to limited visibility and slippery driving conditions. Drive with extreme caution, or pull over and park.

After the hazard is passed, do check your home, and especially your catchment system, for any impact that may affect your water quality.

This is precautionary information for your safety in the event that there is a Halemaumau explosive event. We want everyone in the Volcano area to be ready, and to remain safe. Do keep yourself informed and on the alert.

At 4:39 p.m. on Friday, the USGS Hawaiian Volcano Observatory had this update on the summit:

Tiltmeters at the summit of Kīlauea Volcano continue to record deflationary tilt. Based on this and field observations of the past two days, the lava lake level continues to drop. Rockfalls from the steep crater walls have generated small ash clouds mixed with white condensed water vapor intermittently throughout the day. These ash clouds have been relatively low concentration and have risen only a few thousand feet above the ground generating very localized ashfall. More explosive activity generating larger ash clouds remains possible.

Earthquake activity in the summit remains elevated. Many of these earthquakes are related to the ongoing subsidence of the summit area and earthquakes beneath the south flank of the volcano.

USGS says more information on volcanic ash can be found at this website.