November 1, 1996

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

A Mauna Loa SW Rift Eruption 240 Years Ago

William D. Westervelt, in his 1916 book "Hawaiian Legends of Volcanoes", recounted a story about the origin of the two hills called "Na Pu`u a Pele," located on the Ka`u coast, a mile west of where the "road to the sea" reaches the ocean southwest of Hawaiian Ocean View Estates. These prominent hills are "littoral cones" formed in pre-European times by explosions as a major lava flow entered the sea.

In Westervelt's account, these pu`u represent the bodies of two ancient chiefs of Kahuku, who were overwhelmed by a lava flow long ago. The chiefs had fallen in love with a beautiful maiden who visited their villages, but they had become suspicious that the maiden was actually Pele because of her temper. When they decided to spurn Pele, she turned into a wrathful old woman whose "hair floated out in tangled masses, whose limbs shown as if enwrapped with fire, and whose eyes blazed forth like lightning."

When the chiefs ran in terror from Pele, she became enraged and "struck the ground heavily with her feet," "earthquakes swept the land of Kahuku," an "awful fiery flood broke forth from the underworld and swept down over Kahuku." The terrified chiefs tried to reach the sea by fleeing north, but then a new flow made them turn back south. Just as the chiefs almost reached the sea, "Pele threw her arms around her former lovers," and the lifeless bodies of the chiefs are preserved as Na Pu`u a Pele.

Careful geologic mapping of Mauna Loa lava flows by HVO geologists has shown that the extensive lava flow surrounding Na Pu`u a Pele must be the same one alluded to in the Hawaiian legend. This flow (the "Hapaimanu" flow) consists of two lobes. Mapping shows that the southern lobe is older, so that refugees fleeing north from the first flow would indeed have been turned back by the later north flow, exactly as told in the legend. The earthquakes caused by Pele stamping her feet are phenomena which must indeed have preceded the Hapaimanu eruption. Carbonized wood from beneath these lavas have been recently dated by the carbon-14 method as 240 +/- 60 "radiocarbon years," or about AD 1660 in calendar years.

This newly dated flow is one of the largest single flows on the lower Southwest Rift Zone and adds to our quantitative knowledge of volcanic hazards in this area. The flow covers about 100 square kilometers of area (more than three times the area of the 1984 Mauna Loa flow) and forms about 11 kilometers of the Ka`u coastline, from Manuka Bay, southeast to Humuhumu Point.

About one third of the modern subdivisions of this area are located on this flow, whose source vents are located between the 5,400 ft and the 6,400 ft elevation, directly above the Hawaiian Ocean View Estates subdivision. Our mapping shows that some 15 eruptions have occurred in this area since the arrival of the first Hawaiians about 1,500 years ago.

The Hapaimanu flow, which formed Na Pu`u a Pele about 240 years ago, was the largest eruption in this area, but it certainly is not the last. Six younger lava flows have been mapped in this region (the latest in 1926), and more will come in the future -- which is why the Hawaiian Volcano Observatory maintains a constant vigil and in conjunction with the Hawaii County Civil Defense Agency, continually strives to educate residents about lava flow hazard on the Island of Hawaii.

Eruption Status; Earthquakes

The current eruption of Kilauea continues without change. There were six felt earthquakes last week. Four M1.9 to 2.6 earthquakes occurred at the summit of Kilauea on the evening of the 25th, and another M 2.1 at the same location on the evening of the 26th. In the late morning on the 29th a M3.1 earthquake occurred offshore of Kona.