Earthquakes Increase Following Collapse of Pu`u O`o

Last updated at 12 p.m.

The Hawaiian Volcanoes Observatory reports increased shallow earthquake activity in the Puna district below Kilauea volcano in the area between Pu’u O’o and Highway 130.

This means an outbreak of lava in a new location could occur. While it is not possible to predict where an outbreak could occur, the area east of Pu’u O’o is a possible location.

A collapse of the Puʻu ʻŌʻō crater floor Monday afternoon on Kīlauea Volcano’s East Rift Zone has prompted increases in seismicity and deformation along a large section of the rift zone, with seismicity currently occurring as far east as Highway 130.

“A outbreak of lava in a new location is one possible outcome. At this time it is not possible to say with certainty if or where such an outbreak may occur, but the area downrift (east) of Puʻu ʻŌʻō is the most likely location, as this is where seismicity and deformation have been concentrated overnight,” Hawaiian Volcano Observatory officials said.

Between about 2 p.m. and 4:30 pm on Monday, April 30, following weeks of uplift and increasing lava levels within the cone, the crater floor at Pu‘u ‘Ō‘ō on Kīlauea Volcano’s East Rift Zone collapsed.

Poor weather prevented HVO from flying over the activity or seeing details of the activity in our web cameras on site.

Following the collapse, HVO seismometers and tiltmeters recorded an increase in seismic activity and deformation from Kīlauea Volcano’s summit to an area about 6 to 10 miles downrift (east) of Puʻu ʻŌʻō. Overnight, this activity localized downrift of Puʻu ʻŌʻō and continued to propagate eastward along the rift zone.

The largest earthquake of this sequence so far was a magnitude 4.0 earthquake just offshore south of Pu‘u ‘Ō‘ō at 2:39 a.m. on Tuesday morning,

Kīlauea’s summit eruption has thus far not been affected by the change at Pu‘u ‘Ō‘ō.

The migration of seismicity and deformation downrift (east) of Puʻu ʻŌʻō cone following Monday’s collapse indicates that a large area along the East Rift Zone is potentially at risk for a new outbreak.

The location of any future outbreak will determine what areas are in the path of new lava flows.

HVO said the situation is rapidly evolving and USGS Hawaiian Volcano Observatory scientists continue to closely monitor Kīlauea’s East Rift Zone and summit.

The County has closed the Kalapana lava viewing area amid the possibility of an eruption, and security has been posted to ensure than no unauthorized persons enter the area.

“We don’t want people hiking in that area, which is downslope from the rift,” Parks and Recreation Deputy Director Maurice Messina said.

Messina said that vendors at the viewing area were told to vacate the area.  He noted that the lava viewing area can draw 500 to more than 2,000 visitors, depending on the level of volcanic activity.

Deformation is the term used to describe change in the surface of a volcano, such as swelling, sinking or cracking, which can be caused by movements in the earth’s crust due to motion along faults, according to the U.S. Geological Survey.

Hawai`i County Civil Defense and HVO advise lower Puna area residents to stay informed of the situation.