Natural Hazards: Earth Processes as Hazards

Course Announcements

  • Attendance: No attendance taken. Get notes from classmates if missed.

  • Lecture Slides: Available on Canvas.

  • Exam Dates:

    • Exam #1: May 7, 2:00-3:15 pm

    • Exam #2: June 4, 2:00-3:15 pm

  • Materials Needed for Exams: Bring a number 2 pencil.

  • DSP Students: Register with DSP office ASAP.

  • Presentation Sign-Up Deadline: May 5.

  • Office Hours:

    • Kelsey Wight: Mon 11:30-1:30 (HSSB 3224)

    • Reeves Erickson: Tues 4-5pm, Thurs 4-5pm (Zoom)

    • Wesley Noble: Mon 12-1pm, Tues 4-5pm (Zoom)

    • Kyle Alves: Mon 1-2pm, Mon 3-4pm (Zoom)

  • TA Review Sessions:

    • Exam 1 Review: May 5/6 5-6pm (Zoom)

    • Exam 2 Review: June 2 4:30-6:30 pm (Zoom)

Grading Breakdown

  • Exam 1: 200 points

  • Exam 2: 200 points

  • Assignments: 100 points total (4 problem sets, each 15 points; presentation 40 points)

Lecture Schedule Overview

  • Week 1:

    • Lecture 1: Intro (Ch 1)

    • Lecture 2: Earth's Internal Structure (Ch 2)

  • Week 2:

    • Lectures 3-4: Plate Tectonics and Seismology (Ch 2 & 3)

  • Week 3:

    • Lectures 5-6: Earthquakes (Ch 3)

  • Week 4:

    • Lectures 7-8: Volcanoes and volcanic hazards (Ch 5)

  • Weeks 5-10: Focus on Tsunamis, Hurricanes, Mass Wasting, and climate change topics, culminating in Exam 2.

Key Topics in Volcanology

Relationship Between Volcanoes and Plate Tectonics

  • Volcanoes are directly related to tectonic plate activity.

Types of Volcanoes

  • Shield Volcanoes:

    • Composition: Basalt

    • Eruptions: Generally not explosive

    • Examples: Hawaiian Islands attributes to low viscosity and low volatiles.

  • Stratovolcanoes (Composite Cones):

    • Composition: Andesitic to rhyolitic

    • Eruptions: Explosive, example includes Mount St. Helens.

  • Calderas:

    • Composition: Rhyolitic

    • Eruptions can be catastrophic, exemplified by Yellowstone.

Volcanic Eruptions

  • Characteristics determined by:

    • Chemical Composition

    • Viscosity (related to SiO2 content)

    • Gas content (volatile substances)

Magma Generation Mechanisms

  • Decompression Melting: Occurs at mid-ocean ridges.

  • Addition of Volatiles: Water content decreases the melting temperature of rocks at subduction zones.

  • Addition of Heat: Hotspots create melted rocks that can form magma (e.g., Hawaii).

Viscosity and Volatiles

  • Higher silica content results in more viscous lava, leading to explosive eruptions.

  • The role of volatiles in magma leads to differences in eruption styles (explosive vs. effusive).

Hazards Associated with Volcanoes

  • Volcanic hazards manifest as ashfall, pyroclastic flows, lahars, and volcanic gases.

  • Importance of understanding volcanic activity allows for improved risk mitigation and disaster response strategies.

Geographical Risks

  • Various regions identified as high-risk due to proximity to tectonic plate boundaries or hotspots.

  • Continuous monitoring of seismic activity is vital in these areas to predict eruptions and mitigate risks.