This November 20 aerial image released by the US Geological Survey shows the farthest downslope breakouts of the June 27th lava flow from the Kilauea Volcano that are still situated around the ground crack system, near the abandoned well site in Pahoa, Hawaii. AFP PHOTO

 Steff Gaulter

Lava is oozing over the landscape of the island of Hawaii, slowly consuming everything in its path. The temperature of the molten rock can reach as high as 900°C (1600°F), so it’s no surprise that nothing in its path can survive. Trees and shrubs ignite instantly, asphalt burns and even a home has been swallowed up by the molten flow.

Living in Doha, it’s sometimes hard to imagine the mountainous, rocky landscapes that can be seen in other volcanic parts of the world. Places like Iceland and New Zealand owe their stunning scenery to volcanic activity, but while these countries can be beautiful, they can also be very hazardous.

The majority of countries that were formed by volcanic activity are still prone to earthquakes and volcanic eruptions to this day. Iceland certainly is, and no one who was trying to fly to or from Europe in 2010 can forget the eruption of Eyjafjallajokull. The volcano with the unpronounceable name erupted, spewing a huge ash cloud high into the atmosphere, triggering the worst disruption to air travel since World War II. A total of 100,000 flights were cancelled, and one million people were unable to fly.

New Zealand is also still very vulnerable to earthquakes. You may remember the devastating earthquake that struck the country’s South Island in February 2011. The quake was a 6.9 magnitude and struck close to the city of Christchurch. This was disastrous, particularly for the eastern sections of the city which were built on a former swamp. Shaking turned water-saturated layers of sand and silt beneath the surface into sludge which squirted upwards through cracks. 185 people were killed in the earthquake, and more than half of the buildings in the central business district had to be demolished.

The island chain of Hawaii is another example of a region that owes its very existence to volcanic activity. The chain was formed as the Pacific tectonic plate (one of the vast slabs of solid rock which make up the earth’s surface) moved slowly above a volcanic hotspot. As the plate is constantly moving, the hot spot caused volcanic islands to form and then carried them away, so the volcanoes slowly became extinct. This process is painfully slow; an underwater volcano called Loihi is located off the southern coast of Hawaii Island. This volcano has not erupted since 1996, and is expected to break the surface of the sea in about 250,000 years, adding a ninth island to the Hawaiian chain.

The island of Hawaii, also known as the ‘Big Island’, is made up of five volcanoes: Kohala, Mauna Kea, Hualalai, Mauna Loa, and Kilauea. However, the volcanoes in Hawaii are not the traditional conical shaped ones that you might first imagine when you think of a volcano. Instead they are known as ‘shield’ volcanoes, which are generally broad masses with shallow-sloping sides.

Like other volcanoes, shield volcanoes form when molten rock from inside the Earth reaches the surface, and generates lava, ash and volcanic gasses. However, the shape and nature of a volcano depends on the viscosity of the molten rock. The lava in a shield volcano is not very viscous, and therefore flows relatively easily. This means the lava can flow easily for many kilometres. It cannot pile up around the edges of the volcano and therefore creates gently sloping sides.

The good news for the people living near a shield volcano is that they are much less dangerous than other types of volcanoes. The eruptions are not usually explosive and unlike Iceland’s Eyjafjallajokull, they won’t produce the gas and lava that soars into the air. Instead the lava simply flows down the shallow mountainside. Although this lava has low viscosity, it is still very slow flowing and generally you would be able to avoid it if you were in a car, or even just on foot.

Hawaii is home to the world’s largest shield volcano, Mauna Loa. However, it’s Kilauea which is far more active. Kilauea is one of the most active volcanoes in the world and has been erupting continuously since 1983. Yet despite its active nature, it’s still relatively safe to approach. It’s situated in Hawaii Volcanoes National Park and is one of the most accessible volcanoes in the world; you can walk down a short trail to peer into its crater.

Although the molten rock moves slowly, it does gradually make progress. Over the last thirty years that it has been erupting, it has wrecked dozens of the surrounding buildings and landscapes, including the Royal Gardens and parts of the town of Kalapana. Now a section of the lava is creeping towards the small village of Pahoa. One portion of the molten rock has engulfed the Pahoa cemetery and as the lava burns the surrounding grass and vegetation, the air quality has deteriorated.

The real concern for the locals is that no one can predict exactly where and how fast the flow will spread. The lava flow is simply monitored and the residents of Pahoa are advised accordingly. It is impossible to tell if they will need to evacuate next week, or next month. Some of the residents have already fled, abandoning their homes. We may not have beautiful mountains in Doha, but at least we can sleep easy in our beds, without the fear of an erupting volcano.

 


 

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