Map of flows from Pu`u `O`o: 15 December 2003

Map shows lava flows erupted during 1983-present activity of Pu`u `O`o and Kupaianaha. Shades of red denote Mother's Day flow, which began erupting on May 12, 2002 and continues to the present. Darkest shade indicates lava flows erupted in November and December 2003. Yellow stars indicate centers of recently active, or still active, rootless shields. New shields often form, so it is hard to show all shields on this map. Amalgamated Bend shield is near site of former August 9 rootless shield shown on map.

Through September and into early October 2003, lava was moving along the east and west sides of the Mother's Day flow. The east-side lava (known as the August 9 breakout) came from the August 9 rootless shield, itself fed by the main Mother's Day tube from Pu`u `O`o. The west side lava, known as the Kohola arm of the Mother's Day flow, branched off the tube system below the rootless shield.

In early October 2003, the August 9 breakout stopped moving, the Kohola died back to a trickle, and the one labeled rootless shield gained prominence. By October 16, however, the shield had partly collapsed, leaving several drained perched ponds behind. Upstream from the shield, many hornitos and small flows formed over the Mother's Day tube. Soon thereafter, other rootless shields began to form over the Mother's Day, August 9, and Kohola tubes. These shields have been active throughout November and December.

Vents in West Gap Pit became active in early October, were quiet for 3 weeks, and then resumed intermittent activity that continued well into December. Other vents were also sporadically active in Puka Nui (near West Gap Pit) and in the crater of Pu`u `O`o.