Volcanos: No Longer A Danger
600 Million people are in danger of dying a horrifying death at this very moment (Mountains). That is the number of people who live near an active volcano. To save the lives of so many would require a method to predict exactly when the volcano will erupt, and scientist might not be far off. Using gas releases, spectrometers, and satellite images volcanologists at the United States Geologic Survey (USGS) are nearly able to determine when a volcano will erupt, and how dangerous it will be (USGS). To better understand of the purpose of these volcanologists, and the magnitude of what they have accomplished, we should first know how dangerous a volcano can be.
Dangers: Lava, Pyroclasts, Lahars, and Gases
There is a reason why ancient peoples would compare looking into a volcano as looking into the entrance to hell itself. When a lava is first ejected from a volcano it can be up to 1,200 C or 2,200 F (Cain). The temperature and viscosity, which describes the thickness and texture of the magma, are controlled by the minerals included in the lava. Felsic lavas are made of igneous (volcanic) minerals, which are made of elements like feldspar and quartz, and are the coolest flows between 650-750 C or 1200-1382 F (Cain). The hottest of lavas, which erupt at temperatures over 950 C, or 1742 F, are the Basaltic lavas (Cain). Basaltic lavas are made of igneous minerals such as Plagioclase, Augite, and Magnetite (Cain). It’s clear for us to see that lava flowing at such high temperatures would be deadly; however, it is not just the lava that makes an eruption dangerous.
Other than the lava flow, there are two deadly flows that come with a volcanic eruption, and we must be prepared for them. The first is a pyroclastic flow. Pyroclastic flows are the most dangerous part of a volcanic eruption, and as you can see from the illustration, they are made of a mixture of hot lava, pumice stone, and volcanic gases (Pyroclastic). They move at speeds up to 430 MPH and can retch temperatures up to 1830 F (GCSE). That’s about a hundred MPH faster than the famous bullet trains of Japan. These flows will sweep across a valley as if the hand of Death himself was sweeping through the land. If the mixture of lava and stone doesn’t burn us alive the deadly gases will have us suffocating and as the scientists at USGS say, “Pyroclastic flows destroy nearly everything in their path”. The only way to combat these dangerous forces is to be able to accurately determine when a volcano will erupt, and at how much damage it will insue.
The second flow previously mentioned is a lahar, which comes from the indonesian word meaning a hot mixture of water and rock (Pogram). Lahars can grow to be over 10 times their initial size, and when moving downhill can exceed 120 MPH (Program). This occurs because as the lahar moves down the side of the volcano it continues to pick up anything in its path, until reaching land that is flat enough to slow it down. This is best explained by the experts at USGS when they said that, “The initial flow may be relatively small, but a lahar may grow in volume as it entrains and incorporates anything in its path – rocks, soil, vegetation, and even buildings and bridges…large lahars can crush, abrade, bury, or carry away almost anything in their paths”. The physical lahar taking lives isn’t the only thing we must be worried about when considering the dangers. Lahars are also known for trapping people in. By destroying bridges, polluting the air, and leaving behind rivers of boiling water Lahars can make it impossible for people to escape to safety, or for others to bring resources in (USGSL). Now that we know the true catastrophic effects of a volcanic eruption we know why scientists have been working so diligently to understand when/how a volcano will erupt. Volcanologists worldwide have come to the conclusion that the defining factor of a volcanic explosion is the dissolved gases found within the magma, or lava that has yet to erupt.
The most common gas found in a volcano is water vapor; with sulfur dioxide, carbon dioxide, and hydrogen found in smaller amounts (Grocke). Dr. Oleg Melnik, professor at the university of Bristol in Moscow, explains that when magma moves towards the surface the pressure applied to the magma lessens; and as the pressure levels decrease the amount of space within the magma increases forcing air bubbles to form. These air bubbles create an interconnected system, which controls when the volcano will erupt and with what force (Melnik). This knowledge is useful to us as we have realised that by focusing our efforts on calculating how much gas is being produced by the volcano, we will then be able to anticipate when the volcano will erupt.
Solving the Problem: Methods
Calculating the amount of gas within the magma of a volcano is no simple task, as the gases being produced are hazardous to the health of those near it. Chemist for Oregon State University, Dr. Shown R Decker, states that, “For most people even a brief visit to a vent is a health hazard” and “Long term exposure to volcanic fumes may aggravate existing respiratory problems…cause headaches and fatigue in regularly healthy people”. Certain atmospheric conditions can also trap in the gases and make their effects more severe, along with limiting the visibility of those working on/near an active volcano (Decker). In order to accurately foresee when an eruption will occur we must have methods in place to test the volcanos in question.
Testing a volcano for gas release is a dangerous, and painstaking process, but necessary in order to comprehend an active volcano. “Understanding volcanic gases is essential to understanding how and why volcanoes erupt….It is dissolved gases that cause volcanoes to erupt and it is gases emitted at the surface that can cause hazards and changes in climate”, explains Dr. Stephanie Grocke, of The Smithsonian National History Museum previously at the University of Iceland. Dr. Grocke’s specialty is working with the correlation spectrometer, or COSPEC, which was initially made to measure the amount of pollution. Volcanologists soon found that the machine could be used to measure the amount of sulfur dioxide in the air surrounding a volcano. The numbers collected are compared to international standards for light passing through the stratosphere, which we can use to then calculate how soon the volcano will erupt (Grocke). Examining the air for chemicals is a significant part of determining when a volcano will explode, so there are multiple ways to do it.
The Advanced Very High Resolution Radiometer (AVHRR) is a satellite that can be used by volcanologists to test the aerosol layer, a layer that is predominantly water based, created by an erupting volcano. As seen in the image AVHRR has been used to make a base line for the amounts of different gases found on the planet on a ‘normal’ day (AVHRR). The data extracted from an active volcano by AVHRR can be compared to the base model, and the exact amount of gas being released can be calculated.This method was used by Dr. Stowe when measuring the effects of the Mt. Pinatubo eruptions of 1992. The AVHRR was used along with LIDAR, “a ground-based remote sensing method”, that is used to measure circulation and accumulation of different gasses in the atmosphere (Grocke). Total Ozone Mapping Spectrometers (TOMS) are also used to test the ozone layer. TOMS are used to detect the amount of sulfur dioxide in clouds surrounding the volcano (Grocke). A column has been created illustrating the moderate amount of sulfur dioxide found in the ozone, and the numbers derived from TOMS can be correlated to recognize differences between an active and inactive volcano (Grocke). Though all of these methods have their weaknesses, we can still be assured the data extracted from the machinery is pertinent to the development of techniques that will one day be able to forecast when a volcano will erupt, as simply as we might forecast the weather.
Nearly There
Historic volcanos, such as the 1815 Tambora Volcano which killed 10,000 people directly and another 80,000 because of loss of homes and food, are so disastrous because the people had no way of knowing when a volcano was going to erupt (Decker). “No longer shall the cities be destroyed!” exclaims Dr. Thomas Jagger, Founder of Hawaiian Volcano Observatory when discussing the future of volcanic eruptions. Volcanologists worldwide have worked day and night to come up with a solution to the catastrophe that has killed so many; and by way of Satellites, Spectrometers, and our knowledge on the inner workings of volcanoes, we are nearly there.
Works Cited
1) Cain, 2016, What is the Temperature of Lava?: Universe Today.
2) Decker, R., and Decker, B. Volcano World: How do volcanoes affect people? | Volcano World | Oregon State University.
3) GCSE Bitesize: Key facts, 2014, BBC.
4) Grocke, Stowe, Symonds Estimates from Rocks, Minerals, and Inclusions: Measuring Volcanic Gases.
5) Jaggar, T.A. Predicting Volcanic Eruptions: USGS Volcano hazards Program – Predicting Volcanic Eruptions (Text Only)
6) Melnik, O., Barmin, A., and Sparks, R., 2005, Dynamics of magma flow inside volcanic conduits with bubble overpressure buildup and gas loss through permeable magma: Journal of Volcanology and Geothermal Research, v. 143, no. 1-3, p. 53–68, doi: 10.1016/j.jvolgeores.2004.09.010.
7) Mountains, volcanoes and earthquakes Volcanoes: A suitable home?
8) Program, V.H., 2017, Lahars: USGS: Volcano Hazards Program.
9) Pyroclastic flows move fast and destroy everything in their path. USGS: Volcano Hazards Program