Soft Story
Definition
A building story (usually ground floor) that is significantly weaker than the floors above, often due to large openings like garages or storefronts. Soft stories are the most common collapse mechanism.
Example
The 1994 Northridge earthquake collapsed 200+ soft-story apartment buildings.
Related Terms
Related Guides
The Soft Story Problem: Why Some Buildings Collapse
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The 1989 Loma Prieta Earthquake: The World Series Quake
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Related Case Studies
The 2023 Turkey-Syria Earthquakes: A Double Mainshock That Killed 59,000
The deadliest earthquake disaster of the 2020s, notable for its unprecedented double mainshock sequence and the subsequent criminal prosecution of contractors for building code violations.
The 2010 Haiti Earthquake: How a Magnitude 7.0 Killed 316,000 People
The deadliest earthquake relative to magnitude in modern history, demonstrating that building quality and governance -- not earthquake size -- determine whether people live or die.
The 1995 Kobe Earthquake: The Disaster That Transformed Japan's Building Codes
The earthquake that exposed fatal weaknesses in Japan's pre-1981 building stock, leading to the most sweeping seismic engineering reforms in history and proving that building codes save lives.
The 1994 Northridge Earthquake: America's Most Expensive Seismic Event
America's most expensive earthquake, which revealed that thousands of modern welded steel moment-frame buildings had suffered hidden brittle fractures in their connections.
The 1989 Loma Prieta Earthquake: The World Series Quake That Woke Up California
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Related Tools
Frequently Asked Questions
The epicenter is the point on the Earth's surface directly above the hypocenter (focus) where the earthquake rupture begins. It is typically reported as latitude and longitude coordinates. The strongest shaking usually occurs near the epicenter, though local soil conditions and fault geometry can shift the zone of maximum damage.
A seismograph (or seismometer) is an instrument that detects and records ground motion caused by seismic waves. Modern broadband seismometers can detect movements smaller than the width of an atom. Networks of seismographs around the world enable scientists to locate earthquakes and determine their magnitude within minutes.
P-waves (primary waves) are compressional waves that travel fastest through rock, arriving first at seismic stations. S-waves (secondary waves) are shear waves that arrive later but cause more ground shaking. P-waves travel through solids, liquids, and gases; S-waves only travel through solids. The time difference between them helps determine earthquake distance.
The hypocenter (or focus) is the point within the Earth where an earthquake rupture initiates. It is described by latitude, longitude, and depth. The vertical distance between the hypocenter and the surface directly above is the earthquake's depth, which strongly influences how the earthquake is felt at the surface.
Seismology is the scientific study of earthquakes and the propagation of seismic waves through the Earth. It encompasses earthquake detection, location, and characterization; Earth's internal structure; seismic hazard assessment; and earthquake engineering. Seismologists use data from global seismograph networks to study these phenomena.