Seismic Wave
Definition
An elastic wave generated by an earthquake or explosion that propagates through the Earth. Seismic waves carry the energy released at the earthquake source to distant locations.
Example
Seismic waves from nuclear tests are detected by the CTBTO monitoring network.
Related Terms
Related Guides
What Is an Earthquake? A Complete Introduction
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Surface Waves: Love Waves and Rayleigh Waves Explained
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How Long Do Earthquakes Last?
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The 2011 Tohoku Earthquake and Tsunami: A Complete Analysis
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The 2010 Haiti Earthquake: Disaster and Response
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The 1960 Great Chilean Earthquake: The Largest Ever Recorded
At M9.5, the 1960 Chile earthquake remains the most powerful ever recorded. Its tsunami crossed the Pacific Ocean and reached Japan.
The 1964 Alaska Earthquake: The Great Alaskan Quake
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Related Case Studies
The 2018 Sulawesi Earthquake: Strike-Slip Tsunami and Catastrophic Liquefaction in Palu
The earthquake that defied three textbook rules: strike-slip faults generated a destructive tsunami, the rupture propagated at supershear speed, and liquefaction flows traveled 700 meters on nearly flat ground.
The 2011 Tohoku Earthquake: How a M9.1 Megathrust Triggered Japan's Triple Disaster
The only earthquake in recorded history to trigger a simultaneous earthquake, tsunami, and nuclear disaster, fundamentally changing how nations assess cascading risk.
The 2004 Indian Ocean Tsunami: The Deadliest Earthquake Disaster of the 21st Century
The deadliest tsunami in modern history, killing 227,898 people across 14 countries, whose aftermath created the Indian Ocean Tsunami Warning System and transformed global disaster preparedness.
The 1985 Mexico City Earthquake: The Resonance Disaster That Defied Distance
The definitive case study in site amplification and structural resonance, where lake-bed sediments selectively amplified 2-second seismic waves that destroyed mid-rise buildings 350 km from the epicenter.
The 1970 Ancash Earthquake: The Deadliest Earthquake in South American History
The deadliest earthquake in South American history, where a 50-million-cubic-meter avalanche from Mount Huascaran traveled at 300 km/h to bury the town of Yungay, killing 92% of its population.
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.