The Hawaii Volcano Observatory (a geologic organization dedicated to facilitating the monitoring of the volcanoes on Hawaii) and the Hawaii Volcanoes National Park give extensive warning of the hazards caused by the volcanic activity in Hawaii. During our time on the coastline where the lava was actively flowing, we had to take into account many of these safety hazards.
First of all, it is definitely a good idea to always wear good, sturdy shoes and long pants when walking on the lava flows. When lava cools, it turns to glass. Anyone who has ever broken a window or shattered a light bulb can imagine how painful it would be to walk across the shards with bare feet. The lava on Hawaii is much the same. Falling on this jagged lava (brown color) could result in serious lacerations.
|Photo by Ed Epp|
|Photo by USGS
Another hazard that lava presents occurs when molten lava enters the sea. The problem with lava entering the sea is that 2000 degree F, molten, material is hitting a surface that is 75 degrees F. The water instantly cools the lava, and in the process, literally rips it apart, sending hot, steaming debris in every direction. Sometimes these explosions can be so powerful that steaming hot debris can land distances of more than three hundred feet away!
When lava enters the ocean, new land is created in a fan-shaped platform known as a lava delta. These deltas are formed from the accumulation of the debris that exploded as the lava hit the water.
Sketch by J. Johnson, 2003
Venturing out onto these platforms would be perilous. These platforms are rarely long lived features, and are prone to collapse into the ocean at anytime. When this happens, the hot magma still beneath the platform explodes as the sea water rushes in. Often, areas the size of several football fields can disappear overnight.
Staying clear of the sea cliffs is also a good idea. Some of these cliffs have wave cut overhangs that could give way under a person’s weight.
|Photo by Tim Lincoln|
Being aware of volcanic gases is important to assure that visitors to Hawaii’s active volcanoes are safe. Gases, such as sulfur dioxide, carbon dioxide, and carbon monoxide, among others, are very toxic in dense enough concentrations. The smell of sulfur dioxide is often noticeable near volcanic vents and fumaroles on the island (it smells like rotten eggs). Its presence is also apparent as a yellow discoloration of the rocks around the vent. These vents can emit hazardous concentrations of sulfur dioxide, so the best way to stay safe in and around the vents is to simply keep a conservative distance from anything that hisses or steams.
Sulfur Banks. Toxic gases seep up through this fumarole and are released through cracks and fractures between the rocks.
Photo by Jason Kennedy
Another danger is to walk in and around the lava flows when there was a high risk of methane explosions. These explosions happen when plants are overrun by the lava and burn beneath it. The methane released by the combustion can flow through the soil and then explode unexpectedly.One hazard that we were extremely cautious about was walking on the lava flows at night. Since our visibility was so reduced, the flows were downright scary in the dark. Not only was the heat around us very disorienting, but even with the aid of our flashlights, we could tell which rocks beneath our feet were hot and which weren’t. Often, they were too hot to touch, and we could feel the heat penetrating through the soles of our boots. At most places we could see down into the cracks in the lava. About a foot down, the rocks were red hot. It was just really disconcerting, so we decided not to venture out onto them.
Photo by Tim Lincoln
What we couldn’t believe was the fact that most people didn’t realize the danger. We saw folks in shorts and tennis shoes, with strollers and toddlers, walking onto the flows, at night, like it was Disney World. The lava is not a forgiving element to people who don’t respect its danger, and two days later we read about someone who fell in at night and had to be life flighted to the nearest hospital. Remember, there are no rangers on duty at night, and most cell phones don’t work on that point of the island.On the longer term, active lava flows present a significant hazard to man-made structures that cannot easily be moved from the lava’s path. Somewhere beneath the lava flow used to be a two lane highway. The area through which lava is flowing on Hawaii is actually rather small, so I guess that these signs along the road simply ran ou