Directions: After reading “Kilauea curiosities,” students can connect the article to core concepts in chemistry, physics, biology, earth science and public health by discussing the following questions in groups. There’s one question for each section of the article, tagged with subject areas. Summaries of the sections and key terms are supplied on the “questions and resources” sheet below.
Suggestion for structuring discussion: Post the five questions that follow in five areas of the classroom. If you think it will encourage a more informed discussion, include the section summaries and key terms. Break your students up into five groups and ask each group to visit each discussion prompt and write down their answers. Reconvene to share as a full class if time permits.
Five discussion questions:
Section 1, Earth Science and Chemistry
Section 1 of the article states that the type of lava affected the explosiveness, or magnitude, of Kilauea’s eruption. Why would the amount of silica or gas bubbles in basalt lava, as compared with andesite lava, affect the magnitude of the eruption? What other factors would likely affect the magnitude of a volcanic eruption? Explain how a change in magnitude of a factor might affect the explosiveness of the eruption.
The composition, temperature and gas content of the magma all affect the explosiveness of an eruption. Andesite lava has a higher dissolved gas content than basalt lava, making it more explosive. Similar to opening a can of soda, as the external pressure on a solution with dissolved gases decreases, the dissolved gas becomes less soluble and is no longer held in solution. As magma rises toward the surface of the Earth, the external pressure decreases, and dissolved gases are no longer held in the magma. The amount, volume and pressure of the undissolved gases continue to increase until the system erupts to release the built up pressure. Magmas with greater amounts of dissolved gas are generally more explosive.
Magma’s temperature affects its viscosity, or its resistance to flow. The higher the temperature, the lower the viscosity. The percentage of silica in magma also affects the magma’s viscosity: The more silica present, the more viscous the magma and the more explosive the eruption.
Other factors such as eruption direction and location could also affect its explosiveness.
Section 2, Environmental Science, Public Health and Engineering Design
Thanks to data collected and an understanding of Kilauea’s internal plumbing, scientists were able to warn colleagues elsewhere about a possible eruption. Name and describe an instrument scientists use to predict and study potential volcanic activity. Imagine you were a scientist witnessing the collapse near the summit, write the warning message you would send your colleagues. What specific information about the volcano might you provide? If you were addressing local residents about a volcanic threat, what information would you provide and why?
Scientists use tiltmeters to study volcanic activity. Tiltmeters measure changes in the slope of the ground. The instruments can be used to measure changes on the surface of volcanoes caused by moving magma. Magma moving out of an area will cause the ground to depress. Magma moving into an area will cause the ground to swell. Other instruments to consider include seismometers and seismographs, GPS, infrared and time-lapse cameras, spectrometers for measuring volcanic gases, thermocouple probes for directly measuring lava temperature, electromagnetic ground conductivity mapping for determining how much magma is moving underground, and infrasound sensors to forecast eruptions before they happen.
Warning: At 3:00 p.m., the northeastern rim of the summit crater began collapsing. The collapse is large enough that it could trigger earthquakes. Expect tremors in your area and do what is necessary to keep yourself safe. For scientists working in the field, the most important information might be signs of ground deformation and other observations that could indicate an imminent eruption, as well as the likelihood of lahar flows in the area and volcanic gas levels in the atmosphere.
Students addressing local residents about a volcanic threat might include information on where the lava is flowing, where fissures are likely to erupt and the levels of gases and vog in the air. If possible, it would be good to include the area in danger and the time frame for the threat. This information is important for residents in case they need to stay inside due to poor air quality or evacuate because of the danger posed by other hazards. The information provided should be accurate and informative but should be presented in a way that does not panic the public.
Section 3, Chemistry and Physics
Kilauea’s caldera collapse is described as a “piston-style” collapse. Based on the definition of a piston and the article’s description of the collapse, how is the collapse like a piston and how is it unlike a piston? Draw a diagram to represent the progressive cycle of the collapse at Kilauea. Within your diagram, show the forces that explain each small collapse within the larger progression. Try to incorporate the quantitative data mentioned in Section 3 of the article into your diagram.
As magma rises closer to the Earth’s surface, the pressure on the surface causes the land to be pushed upward. The elevated land is held up by the pressure and upward force of the expanding magma. Once the pressure inside the magma chamber is too great, the volcano erupts and the magma escapes the magma chamber. Once the chamber has lost at least some of its magma, there are no longer upward forces from the magma holding up the overlying rock, so the rock collapses. The collapsing rock forms what is called the caldera. If the collapsing rock stays as a single block of land and loses elevation in a level manner, it is called a piston-style caldera collapse. The caldera, similar to a piston, is collapsing within a close-fitting chamber due to a drop in the force from the chamber below. Just like the piston, the caldera will continue to collapse until the upward pressure is equal to the downward pressure. The motion of a caldera collapse can be similar to the motion of a piston, but unlike a caldera, a piston is the moving part of a larger, man-made system, such as an engine or pump.
Student diagrams should show approximate force vectors of the magma chamber in equilibrium with the collapsed caldera. Students should show that the overlying land collapsed a distance of at least 500 meters.
Section 4, Biology and Environmental Science
How do you think the volcanic lava flow affected the marine ecosystem? Give a specific example of a complex interaction that exists among common plants and animals in a marine ecosystem. How would the ecosystem change over a period of time after the volcanic lava enters the ecosystem: What would change right after the lava event? What about in the weeks, months, decades and centuries that follow? Think about ecological succession, the stages of regrowth and the primary factors of evolution.
When lava eventually makes its way to the ocean, the water boils. The temperature increase can have a devastating effect on marine life. Fish, sea turtles and creatures trapped in tide pools often cannot escape the lava flow. Coral reefs that become covered by lava are destroyed. Reefs on the border of the lava flow are very likely to be stressed because of the hot water and large amount of sediment. Corals provide homes and food for many types of marine organisms. If reefs are destroyed or stressed, that could have a negative impact on the organisms that rely on corals.
Encourage students to think about ecological succession — the process by which ecosystems reestablish themselves after a natural disaster or human disturbance. Students might be more familiar with succession as it plays out in a forested habitat. What parallels can they draw to marine ecosystems? In the first few weeks and months after an eruption event, pioneer species including bacteria, algae and some microscopic predators are the first to colonize. These pioneer species help create an environment that’s appropriate for less hardy species. In the months following the eruption event, when conditions are more hospitable, new coral larvae might move in. But rebuilding coral reefs can take decades. As reefs grow, creatures such as sponges, anemones, fish, eels, crustaceans, turtles and more populate the area. But current global environmental conditions may impact reef growth. Stressors such as increasing ocean temperatures and ocean acidification may affect the ability of corals to bounce back to the form seen before the eruption.
It’s hard to predict what will happen in the centuries that follow; there are so many variables at play. But encourage students to consider the ways in which a changing environment might influence species and how species changes might shape reef evolution over time. Factors at play in established populations include the potential for species to increase in number, the heritable genetic variation of individuals due to mutation and sexual reproduction, competition for limited resources and the proliferation of organisms able to survive and reproduce in the environment.
Section 5, Environmental Science and Public Health
Section 5 of the article discusses the high levels of sulfur dioxide produced by Kilauea. Why is volcanic smog, or vog, a threat to local residents? What other threats might exist for local residents during an eruption, and how might these threats impact daily life? How does an active volcano affect its local environment more generally? What about the global environment? How would you go about creating a plan to mitigate one of the negative effects?
Health effects of vog exposure include eye, nose, throat and skin irritation, coughing, chest tightness and shortness of breath, fatigue and dizziness. People with asthma, cardiovascular disease and older adults might be at the highest risk for such health effects. Vog might also limit visibility on roads and for planes, and cause damage to jet engines. Other threats from volcanic eruptions include pyroclastic flows, when hot gas and rock race downhill; mudflows called lahars; and lava flows. Volcanic eruptions come with risks of avalanches, earthquakes and tsunamis. These threats may lead to evacuations, damage to homes and infrastructure and reductions in local and regional travel. Local agriculture, fishing and tourism may suffer.
Volcanic activity can wipe out plants and destroy terrestrial and aquatic habitats, alter weather patterns and change air and soil composition. Large eruptions can eject enough gas and dust into the atmosphere to reduce the amount of solar radiation reaching the planet and thus have a cooling effect. Conversely, volcanoes can also belch greenhouse gases into the atmosphere, which can have a warming effect over millions of years.
Since we can’t control volcanic eruptions, the best ways to reduce deaths from volcanic activity are to increase public awareness and understanding of the risks and to set up monitoring, warning and evacuation plans. Some such plans are already in place, for example volcano-alert notification released by the USGS Volcano Observatory. Encourage students to consider what they would need to know to develop an effective and safe evacuation plan. Students might suggest talking with local residents about the dangers of eruptions and researching evacuation plans that have worked for other natural disasters.
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