Learning and teaching resources on Cascadia volcanoes and their associated hazards are provided in this section. We explain the origins of and chemistries of magma and how these are related to plate tectonics in general and Cascadia regional plate tectonics in particular. The types of volcanoes and the explosiveness of their eruptions are addressed by examining the “three Vs of volcanology”, viscosity, volatiles, and volume. Major volcanic provinces and the importance of volcanic rocks in the geologic history of the Pacific Northwest are outlined. Cascadia volcanic hazards include ash flows, ash fall, and volcanic mud and debris flows. We provide a short introduction to methods of monitoring volcanic activity and warning signs of impending eruption.
We recommend that you start by viewing the Cascadia Volcanoes and Volcanic Hazards PowerPoint Presentation. This presentation provides the basic concepts and observations as well as links the teaching resources appropriate for a middle school audience.
A PDF Guide to Cascadia Volcanoes and Volcanic Hazards is also available. This guide is an outline of the Cascadia Volcanoes and Volcanic Hazards topic that contains links to and a table of contents of TOTLE teaching resources on this topic.
Carbon dioxide (CO2) is a major volcanic gas. It is invisible, odorless, and heavier than air. CO2 can accumulate in low-lying areas near volcanoes where unsuspecting people can be asphyxiated by walking into the invisible cloud of CO2 gas. This inquiry-based demonstration shows how CO2 gas produced from vinegar and baking soda displaces oxygen and sequentially snuffs candles representing different elevations.
This 5-page PDF provides a brief introduction to the primary methods of monitoring volcanoes. Approaches to monitoring ground deformation on and around volcanoes are described along with methods for monitoring earthquake activity beneath a volcano and monitoring volcanic gas emissions.
Some volcanic craters form by the violent expulsion of magma (liquid rock) when it reaches Earth’s surface where liquid rock is referred to as “lava”. However, many volcanic craters form by collapse of the rock near the summit of the volcano. When magma pushes up through Earth’s crust, it must displace the surrounding and overlying rocks as it works its way toward the surface. When magma enters a shallow reservoir beneath a volcano, the ground above that magma chamber can “inflate,” pushing the ground upward and outward away from the center of the volcano.
This activity allows teachers to demonstrate how magma intrudes the rocks beneath a volcano, sometimes leading to an eruption of lava from the summit or flanks of the volcano. The gelatin volcano is transparent so students can observe the process of intrusion as the “magma” shoulders surrounding rocks aside to form dikes (vertical igneous rock bodies in the subsurface) or sills (subhorizontal igneous rock layers in the subsurface). The setup time for this classroom demonstration is significant but the payoff can be dramatic!
Bonnie Magura (Jackson Middle School, Portland, Oregon) developed this classroom demonstration of lava viscosity. The viscosity of lava that erupts from a volcano controls the shape of the resulting volcano. In turn, the silica (SiO2) content of the erupting lava controls its viscosity, with higher silica (SiO2) content resulting in higher viscosity.
This Word file is a blank table that students can use to organize their understanding of lava chemistry and properties. The table is designed to be used as part of the Modeling Lava Viscosity Demonstration. The properties of four types of lava (rhyolite, dacite, andesite, and basalt) and the volcanoes that from by eruption of these lavas can be briefly described and / or drawn on the table. The answer key is provided in the completed table “Modeling Lava Viscosity – Table of Volcanic Eruption Styles Answers”.
This Word file is the answer key for the table of lava chemistry and properties. The table is designed to be used as part of the Modeling Lava Viscosity Demonstration.