Volcanic Ejecta from Sunset Crater

Kéyah Math Project development team: Nancy Zumoff, Christopher Schaufele, Steven Semken, Tracy Perkins, Lynn Onken, Philippe Laval, David Gonzales, and Andrew Becenti (deceased).
Kéyah Math Project directed by Steven Semken , Arizona State University; and Christopher Schaufele and Nancy Zumoff, Professors of Mathematics, Emeritus.
Archived at Arizona State University School of Earth and Space Exploration.


Students are provided with equations and geological data to estimate the velocities and impact effects of volcanic bombs that were ejected during the last eruption of Sunset Crater, a young cinder cone volcano in northern Arizona.

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Learning Goals

  • Given quantitative data and a set of equations of motion, calculate the velocities of volcanic bombs ejected during a geologically recent cinder-cone eruption.
  • Assess the potential impact effects if such an eruption were to occur today.

Mathematical Skills
  • Basic algebra
  • Solving equations

Context for Use

This activity consists of a set of quantitative problem-solving exercises that can be used as an in-class activity or an assignment in any introductory course with a unit on volcanism or volcanic hazards, such as:
  • Physical geology or physical geography
  • Geology of National Parks or geology of the Western United States
  • Environmental geology, natural hazards, natural disasters
  • Earth system science or Earth and space science
  • Earth materials
  • Introductory volcanology

Description and Teaching Materials

Teaching Notes and Tips

An Instructor's Guide to all Kéyah Math activities is available online from the Instructor Resources page on the Kéyah Math website.


Students record their work and answers in a word-processor document or a notebook, which can be submitted to the instructor for assessment. Solutions to these problems are available online from the Instructor Resources page on the Kéyah Math website.