Coexisting with volcanoes

Volcanoes have been in the news a lot lately: Etna (Italy), Reventador (Ecuador), Pago (New Britain, Papua New Guinea), Popocatepetl (Mexico)-even our own Mauna Loa. We usually hear about volcanoes only when one is erupting or getting ready to erupt. As a consequence, the news often makes volcanoes look pretty negative. That’s understandable, of course, for some eruptions can cause loss of life and destruction of property. We need to know about that!

But there is another side to volcanoes, a quiet side that generally gets lost in all the doom and gloom. It is this side that attracts people, makes for good living, provides natural resources for society, and inspires awe in those fortunate enough to observe volcanoes in all their glory. And, at most volcanoes, this side prevails for much of the time.

Let’s take Hawai`i. All of the islands were made by volcanoes. There wouldn’t be a Hawai`i without volcanoes. Even the coral reefs are built on volcanic rocks. Long after the islands formed, continued volcanic activity has given them features that we consider beneficial to society. Imagine a Waikiki without Diamond Head, a Mauna Kea without the cinder cones that dot its flanks, or a lower Puna without Kapoho Cone. Hilo Bay exists only because Mauna Loa erupted the Pana`ewa lava flow about 1,400 years ago. Kiholo Bay was enhanced by a Mauna Loa flow in 1859. The list goes on and on.

Think of all the benefits to society from an erupting volcano in Hawai`i, such as Kilauea or, potentially, Mauna Loa. Increased visitation and the needs of those visitors come to mind immediately. Watching lava flows and fountains imparts residents and visitors alike with inspiration, wonder, awe, curiosity, and adventure. Such intangibles are positive additions to our lifestyle, to be balanced against vog and the destruction of property. On balance, most of us would probably agree that we’re fortunate to have Kilauea and Mauna Loa on our island, though we temper this feeling with the terrible reality of the loss of communities, such as Kapoho and Kalapana.

A volcano has to destroy in order to create. This is the yin and yang of volcanoes. A new lava flow may form a bay but has to destroy the beach and whatever else was there first. Volcanic ash has to cover the ground surface before it can create fertile soil.

Destruction usually happens quickly, even by our time scales. A few seconds to a few days-that’s all it takes. But it takes decades or centuries to rebound. This is a time scale hard for us to grasp, one so long and drawn out that we lose track of what is happening. We get out of the habit of thinking about our surroundings as volcanic-until the next eruption starts.

It is possible to minimize problems of eruptions with severe (some would say enlightened) land-use restrictions. Such restrictions require tough choices by society, especially given the generally infrequent occurrence of eruptions on a human time scale. It makes sense to restrict land use in valleys draining a volcano that has a mudflow every few decades, but if that land is fertile or beautiful, what do we do?

Throughout the world, societies on or near a volcano have generally made another choice-simply to coexist with the volcano. The choice has generally been made implicitly; little understanding of the volcano goes into such a decision, and people live there without much knowledge of the hazard but often with a mystical sense of what can happen. Rarely do communities, such as those at the foot of Sakurajima volcano in Kyushu, Japan, make an explicit plan to deal with a volcano, with full knowledge of what could happen in a large eruption.

Such coexistence, whether implicit or explicit, works well most of the time. The benefits of the volcano can be utilized with the understanding that an eruption might change things for the worse, at least over the short haul. An impending eruption is indeed cause for some, at times considerable, concern. But many positive opportunities will likely be found over the long haul, after the eruption has ended. It is not yin or yang, but both.

Activity Update

Eruptive activity of Kilauea Volcano continued unabated at the Pu`u `O`o vent during the past week. Lava flows through a tube system from the vent to the sea. Lava enters the ocean only at the Wilipe`a and West Highcastle lava deltas. The Lae`apuki ocean entry of the east arm of the Mother’s Day flow stopped last week, but another lobe is nearing the coast west of Lae`apuki. Numerous surface breakouts are observed in the coastal flats makai of Paliuli. The public is reminded that the ocean entry areas are extremely hazardous, with explosions accompanying sudden collapses of the new land. The steam clouds are highly acidic and laced with glass particles. The National Park Service has erected a rope barricade to delineate the edge of the restricted area. Do not venture beyond this rope boundary and onto the lava deltas and benches.

There were no felt earthquakes in the week ending on December 5.

Mauna Loa is not erupting. The summit region continues to inflate, but no earthquakes were located in the area for the last seven days.

This article was written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory and is republished by with permission.

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