May 9, 1997

A weekly feature provided by scientists at the Hawaiian Volcano Observatory.

Kilauea: Eruption Status--May 9

Many residents have noticed the bright orange glow coming from Kilauea's eruption site on recent nights. Judging from the phone calls we receive at the U.S. Geological Survey's Hawaiian Volcano Observatory, this sight strikes some viewers as lovely and others as alarming, probably depending on their past experience with lava flows.

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In fact, the source of the glow is fairly benign. Since mid-April, most of the lava erupted from vents on the south and southwest flanks of Pu`u `O`o cone has ponded on relatively flat ground near the southern base of the cone. These ponded flows are responsible for most of the glow, which may vary in intensity from one night to the next, depending mainly on cloud cover.

The ponded flows frequently spill over their own levees to feed channeled a`a flows that move south and southeast. The longer flows have advanced as far as 2.6 km (1.6 mi) southeast of the cone, but none has traveled downslope far enough to be visible from the coastline.

Lava is issuing from two areas on the southwest flank of the cone, both of which are topped by impressive spatter cones 10-12 m (33-39 ft) high. A pit crater below one of these spatter cones intermittently fills with lava and overflows westward. These flows are often visible with binoculars from the Pu`u Huluhulu overlook, a short hike from the Mauna Ulu parking lot in Hawaii Volcanoes National Park.

During the last half of April, the pond at the bottom of the Pu`u `O`o crater was mostly crusted over, but a spatter cone on the southwest edge of the crater floor was intermittently active. Lava spilled from the cone to cover as much as a third of the floor. At the beginning of May, the cone stopped erupting, and no active lava has since been observed inside the crater.

Big Island Earthquakes

A magnitude 3.9 earthquake was felt by residents of Waimea at 8:28 a.m. on Friday morning, May 9. The temblor was located 22 km (13 mi) northwest of Kawaihae at a depth of 41 km (25 mi).