Purpose: This activity will help students understand the tools and monitoring devices that scientists use to study ongoing volcanic activity. They will identify trends in monitoring data and relate those trends to volcanic behavior.
Procedural overview: After watching video clips about the Kilauea eruption and reading online materials, students will answer questions about the methods scientists use to study Kilauea. Students will then look for trends in data available for a specific monitoring technique and identify relationships between data and volcanic behavior. Finally, students will communicate their findings to the rest of the class.
Approximate time: 1 to 2 classes (depending on class presentations)
Activity Guide for Students
Classroom computer projector to show video clips about the Kilauea eruption
Computers for students to access the U.S. Geological Survey websites
Directions for teachers:
Depending on the time available, play some or all of the suggested video clips below to familiarize students with Kilauea and types of volcanic behavior. Discuss the importance of being able to monitor and predict volcanic behavior with your students. Ask students what it might feel like to live close to an active volcano, or if they would consider living close to an active volcano. Once students are finished with the activity, you could revisit the questions to see if student answers have changed.
Kilauea Summit Eruption: Lava returns to Halema‘uma‘u. This excellent 24-minute overview, made before the 2018 eruptions, gives background on Kilauea and how scientists study it.
Help students access and explore the USGS Hawaiian Volcano Observatory website on monitoring techniques at volcanoes.usgs.gov/hvo/hvo_monitoring.html. Include the interactive data map, which shows earthquakes recorded within the last four weeks. Help students start to observe patterns in the data and relate these patterns to volcanic behavior.
Divide the students into four groups as outlined below. Assign each group to read and answer questions about one of the volcano monitoring techniques.
The last question for each section asks students to study available data and look for relationships between the data collected and volcanic behavior. Once students have completed this question, they can summarize and present their findings to the class.
Directions for students: Individually read the article assigned by your teacher and answer the questions that follow as a group. Be prepared to present a summary to the class.
Read “Monitoring earthquakes in Hawaii” at https://volcanoes.usgs.gov/observatories/hvo/hvo_monitoring_earthquakes.html.
1. What did you learn from the first three paragraphs about the seismic network?
Seismic sensors measure ground shaking. Hawaiian Volcano Observatory maintains approximately 60 seismic measuring stations on the island of Hawaii and approximately 40 on other islands across the state.
2. What types of seismic instruments are used to record waves of sound and motion?
(1) Short-period sensors for wave periods of around 1 second. (2) Broadband sensors for wave periods from 0.01 to 120 seconds or higher. (3) Strong motion sensors that can accurately measure shaking even if it is stronger than gravity. (4) Infrasound microphones to measure seismic-related sound waves in air.
3. What characteristics of earthquakes do Hawaiian Volcano Observatory seismologists analyze and why?
Seismic data is analyzed for parameters such as: (1) Hypocenter and magnitude to locate the source and severity of earthquakes. (2) RSAM (Real-time Seismic Amplitude Measurement) to examine trends in average amplitudes over many sensors in a given area. (3) Swarm detection to spot clusters of events localized in time and space that may signal an eruption. (4) Tremor detection to track underground movements of magma and gases.
4. How does the Hawaiian Volcano Observatory report seismic activity?
Via real-time internet updates, news releases and data analyzed and cataloged at a later time.
5. What can you learn from the earthquake data at https://volcanoes.usgs.gov/volcanoes/kilauea/monitoring_kilauea.html? What patterns do you see in the data and how does this relate to the volcanic activity at the time the data was collected? Is there a relationship that you can draw between the data and volcanic behavior?
Read “Deformation monitoring tracks moving magma and faults” at https://volcanoes.usgs.gov/observatories/hvo/hvo_monitoring_deformation.html.
1. What did you learn from the first two paragraphs about deformation monitoring?
Measurements of ground inflation or deflation can help to predict magma flow, eruptions and earthquakes.
2. In what level of detail can Global Positioning System (GPS) sites record ground motion?
Sites that monitor signals from GPS satellites can track ground deformations of less than 1 centimeter in real time.
3. How do tiltmeters record precise changes in ground slope?
Tiltmeters are installed in drill holes 3 to 5 meters below the surface (to avoid interference from weather and other surface effects) and make real-time electronic measurements to report any changes in the local ground slope that might be associated with magma flow.
4. How does Interferometric Synthetic Aperture Radar (InSAR) provide a snapshot of volcano deformation from air and space?
InSAR uses radar images of the ground taken from airplanes or satellites in order to create high-resolution maps of ground deformations.
5. What can you learn from the deformation data at https://volcanoes.usgs.gov/volcanoes/kilauea/monitoring_kilauea.html (click “Deformation Data” on the left side of the screen)? What patterns do you see in the data and how does this relate to the volcanic activity at the time the data was collected? Is there a relationship that you can draw between the data and volcanic behavior?
Volcanic gas group
Read “Monitoring volcanic gas in Hawaii” at https://volcanoes.usgs.gov/observatories/hvo/hvo_monitoring_gas.html.
1. What did you learn from the first three paragraphs about monitoring volcanic gas in Hawaii?
Gases drive volcanic eruptions, so it is important to measure the amount of various gases being produced. Sulfur dioxide (SO2) and carbon dioxide (CO2) are measured in detail, and other gases are measured to some degree as well.
2. How are sulfur dioxide (SO2) rates measured in real time at the Kilauea summit?
SO2 absorbs ultraviolet (UV) light from sunlight, so sensors measure the amount of UV light that penetrates from the sun through a volcanic plume to the sensor, in order to determine the amount of SO2 in the plume. Sensors are mounted facing upward on moving vehicles or on fixed ground stations, or directed across the lava lake.
3. How is the chemical composition of gas emissions measured by Fourier transform infrared (FTIR) spectroscopy?
A FTIR spectrometer analyzes the spectrum of infrared radiation collected by a telescope pointed at lava. Certain absorption or emission lines in the spectrum indicate the presence of different gases. The strength of each line indicates the amount of that gas.
4. How are CO2 and SO2 measured at Mauna Loa Volcano?
These gases are measured via an automated station that is actually located in the crater.
5. What can you learn from the graph of the amount of SO2 released annually during the period 1979–2016?
After a period of inactivity, the East Rift Zone began steadily emitting large amounts of SO2 in 1983. The summit began emitting a huge amount of SO2 in 2008. The Rift emissions drastically decreased in the early 2010s, perhaps because so much gas was being emitted by the summit. Now the summit isn’t emitting much SO2 either.
6. Click on the links at the bottom of the page and describe any useful additional information you find there. What patterns do you see in the data and how does this relate to the volcanic activity at the time the data was collected? Is there a relationship that you can draw between the data and volcanic behavior?
Read “Geological monitoring of Hawaiian eruptions” at https://volcanoes.usgs.gov/observatories/hvo/hvo_monitoring_geology.html.
1. What did you learn from the first two paragraphs about field operations for tracking eruptions and assessing hazards?
Geological monitoring of lava and tephra (ejected rocks) involves some remote monitoring from cameras or aircraft but also a lot of field visits to collect and analyze lava and tephra samples.
2. How do lava-flow maps show the history of Hawaiian eruptions?
Lava flow positions can be recorded using GPS on the ground (slow but accurate) or from the air (fast but less accurate). Combining GPS data from the ground and air with aerial photographs shows how current lava flows are changing the landscape, and also how previous lava flows have built up the existing landscape of Hawaii.
3. How does measuring lava volume over time help to forecast hazards?
The effusion rate (volume of lava erupted per time) can be measured by estimating the flow area and thickness, by measuring the electromagnetic fields of flowing electrically conductive lava or by measuring the amount of associated SO2 released. Increased lava flow volume can be a warning sign for nearby researchers or structures.
4. How do webcams and time-lapse cameras improve interpretation and situational awareness?
Unlike human observers, cameras can be positioned in many different places and can monitor continuously in order to capture interesting events. These images can be combined with other types of measurements to get a better understanding of volcanic behavior and events.
5. How does monitoring lava and tephra chemistry identify changes in magma sources?
Magma that has come via different routes or spent different amounts of time in various locations underground has different fingerprints, in terms of its chemical composition. Analyzing the lava and tephra that result from that magma can indicate the origin, path and history of the magma.
6. Study the webcams at https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_webcams.html that show what Kilauea looks like in real time from many different angles. What patterns do you see in the data and how does this relate to the volcanic activity at the time the data was collected? Is there a relationship that you can draw between the data and volcanic behavior?