Summary of Research on Volcanology - Katie

 For this part of my research, I read The Encyclopedia of Volcanoes (Second Edition) by Haraldur Sigurdsson, Bruce Houghton, Steve McNutt, Hazel Rymer and John Stix and Volcanoes in Human History: The Far-Reaching Effects of Major Eruptions by Jelle Zeilinga de Boer and Donald Theodore Sanders. My goal was to gain a deeper understanding of how eruptions work. We are building a prediction system, so it would behoove us to gain a deeper understanding of the natural disaster we are being tasked to predict. 

• Magma is a substantial mass of molten rock. It is stored 5km to 20km below the surface in underground reservoirs called magma chambers. 
• The constant movement of the magma within these chambers and the vibrations caused by the release of gases are tracked by seismometers. These seismometers don't just track seismic waves from earthquakes, but any large increases of movement within these magma chambers. 
• An eruption is "an event in which magma or rock fragments are expelled explosively and effusively from a volcano." The reason why eruptions are so explosive is because of the build up of gases. As the magma rises, the pressure in the chambers decrease. This causes the gases it expels to expand, and this expansion in turn places buoyant forces on the rising magma. These forces cause the magma to become less dense than the surrounded rock walls of the chamber. When the pressure of gas within a volcano is sufficient to overcome the confining strength of the chamber walls, the magma is violently pushed towards the surface. 
• The glow from molten lava is a result of it's high temperature-- there's nothing actually being burnt. The smoke that's produced is not caused by combustion.-- the ash that's expelled by volcanoes could be turned back into magma if heated at a high enough temperature. 
• "There is no simple answer to the question of what causes an eruption to begin."
• A supply of buoyant magma and escaping gases are essential in order for an eruption to occur. 
• An earthquake is an external trigger that will trigger an eruption. 
• The èruption magnitude is determined by the total mass of material erupted during an eruption. For example, 100 000 tonnes erupted would make the eruption a magnitude 1. 
• The eruption itensity is defined by the rate at which material is erupted. It's measured in kg per second. For example, an eruption rate of 1kg per second is defined as intensity 3. 
• In an average year, 60 volcanoes erupt, and at any time, there are likely to be about 20 volcanoes currently erupting. 
• Many volcanoes which are not actually erupting nevertheless show sufficient signs of unrest that they're considered active. 
• The biggest eruptions tend to occur at volcanoes that erupt least often. The longer the interval of repose between eruptions, the larger the eruption. 
• 1 in 10 eruptions finish in less than a day, and half last less than two months. Fewer than 1 in 5 continue for longer than a year. 
• Lava flows rarely kill people because they move slowly. Less than half of fatalities from from the 500 most dangerous eruptions since the 1600s have been from lava flows. By contrast, pyroclastic flows are the single biggest killer, responsible for 33% of fatalities. This is because they move quickly and it is extremely difficult to build infrastructure that blocks and diverts them. Other major cause of harm as a result of eruptions are tsunamis, famine, disease and respiratory illnesses. 

What are the relevant takeaways from this research? 

That eruptions are uniquely difficult to predict. Apart from very obvious external triggers like a localised earthquake, there are no reliable triggers that can be used as part of our prediction plan. This not only provides a good reason why this wearable is necessary, but shows the importance of connecting our wearable to ground monitoring equipment that's taking in a lot of real time data. Factors that should be paid special attention are increases in the gases being released around the volcano, like carbon dioxide and sulfur dioxide, increases in movement in magma chambers picked up by seismometers and changes in the tilt of the earth that are picked up by tiltmeters, which are the result of a build of gases beneath the surface.