Eruptive Activity Eases At Kilauea Volcano In Hawaii

Irish Weather Online: Eruptive Activity Eases At Kilauea Volcano In Hawaii

Eruptive activity at Hawaii’s Kīlauea volcano has slowed during the last 24 hours, according to the United States Geological Survey (USGS) Hawaiian Volcano Observatory.

The crater floor and lava lake within Pu‘u ‘Ō‘ō collapsed and lava flowed out of its west flank on Wednesday, leading to the closure of some local roads in Hawai‘i Volcanoes National Park.

The USGS stated on Saturday: “In the east rift zone: short lava flows continued to issue from west flank vents; lava continued to trickle onto the collapsed floor of Pu`u `O`o Crater. At the summit, the lava lake surface continued to recede. Seismicity was generally low. Gas emissions decreased but remained elevated from summit and rift zone vents.”

Tourists have since flocked to the site to view dramatic glows from the new Pu‘u ‘Ō‘ō eruption from several vantage points. In addition, Kīlauea’s summit eruption at Halema‘uma‘u crater continues, and visitors can often hear the roar from rocks exploding off crater walls, and can observe a beautiful red glow after nightfall.

Viewing Details: East rift vents and flow field – The only lava erupting from Kilauea volcano’s east rift zone is within Pu`u `O`o Crater within Hawai`i Volcanoes National Park. Access and viewing information can be found here. Access via Kahauale`a Natural Area Reserve is closed by the state of Hawai`i Department of Land and Natural Resources. Kilauea Crater – Hawai`i Volcanoes National Park access and viewing information can be found here.

Wednesday’s activity was preceded on Tuesday by a 3.5 magnitude earthquake, 18 kilometres (11 miles) from the Kilauea volcano. The shallow tremor was recorded at 1:54 AM local time at a depth of 8.5 km (5.3 miles).

According to the United States Geological Survey (USGS) the tremor’s epicentre was located 16 km (10 miles) S (176°) from Fern Forest, 18 km (11 miles) S (185°) from Eden Roc, 42 km (26 miles) S (185°) from Hilo, and 358 km (222 miles) SE (127°) from Honolulu.

Kilauea presently is the world’s longest-lived volcanic eruption. Cycles of activity at the volcano’s summit have been stable for months, however, ever since lava flows at the Kamoamoa Fissure subsided in March 2011.

Deep within Halema’uma’u Crater (which is itself in the Kilauea Caldera) a small lava lake rises and falls as magma ebbs and flows within the volcano. Sensitive instruments monitor these movements by recording the tilt of the summit: decreasing tilt reflects deflation of the magma chamber, increasing tilt inflation. Each cycle of deflation and inflation usually lasts several days.

The above natural-color satellite image from earlier this week shows the summit of Kilauea Volcano, near the southern coast of the Big Island of Hawaii. Kilauea Caldera and Halema’uma’u Crater are both visible, as well as the Hawaii Volcano Observatory and the village of Volcano. The northeast, windward side of Kilauea is covered in dark green Ohia forest. The dry, leeward side is a nearly barren brown. Fresh lava flows are dark gray. A blue-tinted volcanic plume rises from within a pit near the southeastern edge of Halema’uma’u.

The volcanic plume, rich in sulfur dioxide gas, is emitted from the surface of a lava lake. In addition to falling and rising synchronously with the deflation-inflation events of the Kilauea Summit, the elevation of the lava lake varies in a series of fill-and-drain cycles that last minutes to hours. Sulfur dioxide emissions increase when the lake falls, and decrease when the lake rises. This suggests that gas within the lava lake is trapped when the surface of the lava hardens, and pushes the lake up like a piston. When gas is released, the lake level falls.

The bottom image was acquired by the Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite. Caption by Robert Simmon, with thanks to Matthew Patrick, USGS Hawaii Volcano Observatory. Instrument: EO-1 – ALI