U.S. Geological SurveyFact Sheet 074-97  Online Version 1.1

 

| People         on the Island of Hawai`i face many hazards that come with living on or         near active volcanoes. These include lava flows, explosive eruptions,         volcanic smog, damaging earthquakes, and tsunamis (giant seawaves). As         the population of the island grows, the task of reducing the risk from         volcano hazards becomes increasingly difficult. To help protect lives         and property, U.S. Geological Survey (USGS) scientists at the Hawaiian         Volcano Observatory closely monitor and study Hawai`i's volcanoes and         issue timely warnings of hazardous activity. |
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Late in the evening of June 1, 1950, after many residents ofHo`okena-mauka village on the west coast of the Island of Hawai`i hadalready gone to bed, Mauna Loa Volcano suddenly began to erupt. Hot,glowing lava poured from fissures and rushed down the southwest flankof the volcano. In only 3 hours, the swiftly flowing lava traveled 14miles and entered the village. The darkness was lit by flames as themolten lava consumed several houses and the Post Office. By daybreak,lava flows had crossed the area's only road in two places, cuttingoff all escape routes. Fortunately, the residents of Ho`okena-maukaescaped unharmed, but for some it was a close call.

In 1990,         flows of lava from Kilauea Volcano on the Island of Hawai`i invaded Kalapana,         a coastal community treasured for its historic sites and black-sand beaches.         Although the residents were able to evacuate safely, their homes were         incinerated, and by the end of that year all of Kalapana lay buried under         50 feet of lava. In the past 1,100 years, more than 90 percent of Kilauea         's surface has been covered by new lava flows. Ancient Hawaiian communities         were able to easily relocate when threatened by lava flows, but modern         communities, with their greater dependence on permanent structures, highways,         and utilities, are more vulnerable.
The Island of Hawai`i is composed of five volcanoes, two ofwhich–Mauna Loa and Kilauea–have erupted repeatedly inthis century. Another of these volcanoes, Hualalai, last erupted in1801 and has the potential to erupt again within our lifetime. Mosteruptions at Hawaiian volcanoes are not explosive and arecharacterized by the relatively quiet outflow of very fluid lava.These eruptions can still be deadly, because the lava may be eruptedin huge volumes, and on steeper slopes fluid lava can rapidly travelmany miles from its source.