(Activity updates are written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

After 17 days of quiet on Kilauea’s east rift zone, following the March 5–9 Kamoamoa eruption, lava returned to Pu`u `O`o on March 26. The onset occurred during the inflation phase of a deflation–inflation cycle (DI event), and erupting lava formed a small lava lake at the bottom of Pu`u `O`o crater. Activity slowed early in the week, concurrent with the deflation phase of another DI event, and the level of the lava lake subsequently dropped several meters (yards). As of Thursday, March 31, the volcano had begun to inflate again, resulting in an increase in the level of activity at Pu`u `O`o. The lava lake, however, remains more than 95 m (~300 ft) below the east rim of Pu`u `O`o.

A small lava lake was also present deep within the Halema`uma`u Overlook vent last weekend but crusted over or dropped out of view early in the week during the deflation phase of the DI event. The lava lake had reappeared by March 31 during DI inflation. Several small rock falls within the vent cavity have also occurred during the week. Volcanic gas emissions remain elevated, resulting in relatively high concentrations of sulfur dioxide downwind.

One earthquake beneath Hawai`i Island was reported felt this past week. A magnitude-3.1 earthquake occurred at 11:21 p.m., HST, on Sunday, March 27, 2011, and was located offshore, 25 km (16 mi) west of Kailua-Kona at a depth of 34 km (21 mi).
Visit the HVO Web site (http://hvo.wr.usgs.gov) for detailed Kilauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kilauea summary; email questions to askHVO@usgs.gov.

Volcano Watch is a weekly article and activity update written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.