Partial collapse of new land on south shore of Kilauea Volcano, Hawai`i

A prominent lava delta on the south shore of Kilauea Volcano partially collapsed into the sea between about 2:45 p.m. and 7:05 p.m. on May 10, resulting in a large embayment on the western half of the delta. The collapse occurred piecemeal, with each section that slid into the ocean generating a steam plume estimated between about 60 and 300 m (200 and 1,000 ft) high. The plumes also contained lava fragments shattered by the explosive interaction between cold seawater and hot rock of the collapsing delta. Incandescent rock within the delta was exposed immediately after each section collapsed.

Field observations this morning revealed that a scalloped area about 440 m long and 210 m wide (1,450 and 690 ft), amounting to 6.5 hectares (16 acres), is missing from the East Lae`apuki delta. Prior to the collapse the delta measured 1,175 m long and 385 m wide (3,850 and 1,250 ft) at its widest point, with an area of 26 hectares (64 acres).

An apron of rock debris, deposited by explosions accompanying the collapse, covers a 1.2 hectare (3 acre) area inland from the apex of the embayment. Fist-sized rocks were tossed as far as 140 m (450 ft) inland from the edge of the embayment, and one rock 35 cm (14 inches) in diameter was thrown about 120 m (394 ft) inland.

The East Lae`apuki ocean entry has been inactive since mid-March, and no lava was entering the ocean at the time of yesterday's collapse. Lava, however, continues to enter the ocean at Kamokuna about 2 km (1.3 mi) to the east.

East Lae`apuki is the site of the two largest lava delta collapses during the ongoing eruption of Kilauea Volcano, which began in 1983. A 14 hectare (34 acre) collapse occurred in December 1996, and the largest known collapse occurred in November 2005, when 18 hectares (44 acres) of land slide into the ocean over a period of about 5 hours.

Large cracks, formed during last night's collapse, cross the remaining portion of the lava delta as far as about 30 m (100 ft) inland from the new embayment. It is possible that additional collapses may occur without warning.

The sea cliff near East Lae`apuki remains closed by Hawai`i Volcanoes National Park due to significant hazards. Visitors to the area are advised to stay behind the rope line, which is located a few hundred feet from the old sea cliff, and bring sufficient water, food, flashlights, and extra batteries for the arduous hike.

For eruption updates and information on recent earthquakes in Hawai'i, visit the Hawaiian Volcano Observatory website at http://hvo.wr.usgs.gov.

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