March 5, 2011 HAWAI‘I ISLAND, Hawaii — At 1:42 p.m. HST this afternoon, USGS Hawaiian Volcano Observatory (HVO) monitoring network detected the onset of rapid deflation at Pu`u `Ō `ō and increased tremor along Kīlauea Volcano’s middle east rift zone. At 2:00 p.m., Kīlauea’s summit also began to deflate.Between 2:16 and 2:21 p.m., the floor of the Pu`u `Ō `ō crater began to collapse, and within 10 minutes, incandescent ring fractures opened on the crater floor a few tens of meters away from the crater wall. Asthe floor continued to drop, lava appeared in the center of the crater floor, the northeast spatter conewithin Pu`u `Ō `ō collapsed, and an obvious scarp developed on the west side of the crater floor, withlava cascading over the scarp toward the center of the crater.At 2:41 p.m., the scarp on the west side of the crater floor appeared to disintegrate, exposing incandescent rubble. Five minutes later, the collapse of a large block along the east crater wall produced a dust plume.Webcam images showed that the Pu`u `Ō `ō crater floor continued to drop through 4:26 p.m., when fume obscured the camera view. HVO Webcam images can be accessed at volcanoes.usgs.gov/hvo/cams/ Coincident with the collapse in Pu`u `Ō `ō, an earthquake swarm began along Kīlauea’s middle east rift zone in the area of Maka`opuhi and Napau Craters. Tiltmeters showed east rift zone deflation, which continues as of this writing.At 5:15 p.m., an HVO geologist flying over Kīlauea’s middle east zone reported "an eruption in Napau Crater." The eruption is now known to be located between Napau Crater and Pu`u `Ō `ō.Updates on the status of this eruption will be posted on HVO’s Web site at volcanoes.usgs.gov/hvo/activity/kilaueastatus.php According to Jim Kauahikaua, HVO’s Scientist-in-Charge, "This event is remarkably similar to a 1997 eruption in and near Napau Crater, which lasted less than 24 hours."Kīlauea’s summit also continues to deflate, and the lava lake level within the Halema‘uma‘u Crater vent continues to drop, facilitating rockfalls from the vent wall.In response to the current volcanic conditions, Hawai‘i Volcanoes National Park has closed the Chain of Craters Road and all east rift zone and coastal trails, along with the Kulanaokuaiki campground, until further notice.Daily updates about Kīlauea’s ongoing eruptions, recent images and videos of summit and east rift zone volcanic activity, and data about recent earthquakes are posted on the HVO Web site at hvo.wr.usgs.gov