Slow-flowing lava threatens to destroy Hawaiian town of Pahoa

The lava flow from Mt. Kilauea inches closer to the village of Pahoa, Hawaii.

Lava that has been flowing from a Hawaiian volcano for the past week is about to swallow its first houses in a town that is being threatened with destruction.
Mount Kilauea, on eastern side of the Big Island of Hawaii, began spewing a river of molten lava back in June when a new vent opened up, sending a fresh flow of molten rock directly towards the town.
Initially there wasn’t much concern in the nearby town of Pahoa, because for decades whenever the volcano had erupted, its lava always headed south, directly into the ocean. At the same time, a series of eruptions in early 1990 destroyed over 180 homes, highways and historical sites, burying the town of Kalapana with lava as much as 10 meters thick.
This time, however, when the new volcanic crater opened up, fresh lava flow bubbled to the surface and unexpectedly headed northeast, clearly aimed directly at the town of Pahoa, which has a population of about 800.
With temperatures on the south side of 900 Celcius, the lava has continued to creep forward, burning everything it touches, from vegetation to tires and a garden shed so far. But now the town itself is in danger.
Today the National Guard has been sent in to patrol blocked streets and neighbourhoods, and more than a dozen families have already been evacuated. As the unrelenting lava flow advances at speeds of 10 meters per hour, it is now poised to devour Pahoa’s main street and currently has 20 homes in its path.
Scientists are also monitoring for toxic sulfur dioxide gases. The lava flow is unpredictable and no one knows when it will stop.
Mount Kilauea is considered one of the world’s most active volcanoes, having erupted 62 times in the 250 years that it has been monitored – about one eruption every four years. However, it is only one of five currently active volcanoes in Hawaii and it really isn’t the one that has scientists worried.
Mauna Loa, the largest volcano on Earth, is due for an eruption many experts believe – and soon.
It last erupted in 1984, for three weeks. Mauna Loa is so massive that it equals about half of the Big Island's mass. In the past year, it has been showing signs of awakening with rumblings, and the nearly 14,000-foot-high mountain is going through the same geologic motions it went through the last two times it erupted.
Seismologists say faint, shallow earthquakes along the flanks of the summit indicate that fresh magma maybe entering the underground system, following the same patterns seen before the last eruptions.
The potential for destruction would be on a much bigger scale with Mauna Loa – with as much as half of the Big Island covered with past flows from the volcano.
The lava flow we are now seeing from Mount Kilauea has already been going on and off for nearly three decades, but if Mauna Loa is any indication, it could get a lot worse.
Frank Trusdell, a geologist with the Hawaiian Volcano Observatory, said a Mauna Loa blast may last a long time.
"On Mauna Loa, there was a period where lava flows lasted five centuries." he said.
While researchers say there is no need to worried just yet, looking at geological records, Mauna Loa in the past three millennia has on average erupted every six years or so. With a 30 year dry spell, it may mean that it’s overdue to blow its top again.