wunder beta

📘 How does an earthquake shake a city?

A fault is a fracture or zone of fractures where blocks of Earth's crust can move relative to one another. The blocks may be pushed together, pulled apart, or slid sideways. Friction often keeps a fault from moving smoothly, even while tect

5
lessons
~25 min
to learn
Adults
level
Start the course →

What you’ll learn

  1. A fault stores and releases strainExplain how friction, elastic strain, and rupture begin an earthquake.A locked fault stores strain until slip releases energy from a focus.
  2. P and S waves carry the messageDistinguish P and S waves by particle motion, speed, and arrival time.Compressional P waves arrive before slower shear S waves and help locate the source.
  3. The surface turns waves into shakingConnect wave type, distance, frequency, and building rhythm with ground motion.Surface waves and structure-specific response turn seismic energy into city shaking.
  4. Soil decides how the wave is changedExplain why soft sediment and saturated loose soil can increase hazard.Local layers amplify or prolong motion, and liquefaction can remove soil strength.
  5. Read a city's earthquake storySynthesize rupture, waves, site conditions, and structures into one causal model.The observed damage pattern is the product of source, travel, ground, and buildings.

Questions this course answers

What is the focus of an earthquake?

The focus, or hypocenter, is where slip starts below the surface.

Put the fault process in order.

Loading and stored strain come before slip and wave release.

Why does a P wave usually arrive before an S wave?

P waves are faster compressional body waves, so they arrive first.

Match each wave clue to the wave type.

Wave motion and arrival timing distinguish the main clues.

Why can a tall building respond differently from a short building?

Height and stiffness give structures different rhythms.

What does intensity describe?

Intensity varies from site to site, unlike a single source magnitude.

Grounded in trusted sources

  • U.S. Geological Survey, The Science of Earthquakes, https://www.usgs.gov/programs/earthquake-hazards/science-earthquakes
  • U.S. Geological Survey, What are the Effects of Earthquakes?, https://www.usgs.gov/programs/earthquake-hazards/what-are-effects-earthquakes
  • U.S. Geological Survey, Elastic Rebound, https://www.usgs.gov/media/videos/elastic-rebound
  • U.S. Geological Survey, What is liquefaction?, https://www.usgs.gov/faqs/what-liquefaction
  • Incorporated Research Institutions for Seismology, About Seismic Waves, https://ds.iris.edu/aed2/c/aboutWaves.phtml
  • Incorporated Research Institutions for Seismology, How are Earthquakes Located?, https://www.mgs.md.gov/seismic/education/no6.html
  • Wikimedia Commons MediaWiki API, https://commons.wikimedia.org/w/api.php

Every Wunder lesson is built from real, reputable sources — never invented.

Related courses

📘How does a glacier carve a valley?📘How does lightning choose its path?📘How does a total solar eclipse happen?📘How Stars Die📘How Black Holes Bend Light📘How does a comet grow a tail?📘How does a rover drive on Mars?📘How does the eye focus?

Wunder is a personalized learn-anything platform — tell it any topic and it builds a beautiful, fact-checked course in minutes, with narration, a knowledge check, and a college-style University track.

All topics · Home

© 2026 Wunder Learning LLC · Terms & Privacy