s wave
Low (Technical)Technical/Scientific
Definition
Meaning
A type of seismic wave, also known as a shear wave or secondary wave, that travels through the body of the Earth by moving particles perpendicular to the direction of wave propagation.
In seismology and geophysics, an S wave is a transverse body wave that can only travel through solids, not liquids, and is slower than the primary P wave. It causes shearing motion in the material it passes through.
Linguistics
Semantic Notes
Always capitalised when abbreviated ('S wave'). The 'S' stands for 'secondary' (arriving after the P wave) or 'shear'. In non-technical contexts like general media, the full term 'shear wave' or 'secondary wave' may be used for clarity.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Both use 'S wave' predominantly. British sources may be slightly more likely to use 'secondary wave' in explanatory public-facing texts.
Connotations
Identical technical meaning.
Frequency
Equally low-frequency and confined to technical domains in both varieties.
Vocabulary
Collocations
Grammar
Valency Patterns
The S wave [verb, e.g., travels, arrives, is recorded]An S wave from [source, e.g., the earthquake, the tremor]Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Not used.
Academic
Core term in geophysics, seismology, earth sciences, and engineering geology.
Everyday
Rare, except in news reports about earthquakes, often explained as 'the secondary shaking'.
Technical
Primary term. Used to determine earthquake location, magnitude, and Earth's internal structure.
Examples
By Part of Speech
adjective
British English
- S-wave velocity measurements are crucial.
- The S-wave arrival time was logged.
American English
- S-wave data confirmed the hypothesis.
- An S-wave analysis was performed.
Examples
By CEFR Level
- The earthquake had two main shakes; the S wave was the second one.
- Scientists use the time between the P wave and S wave to find how far away an earthquake is.
- Because S waves cannot travel through the liquid outer core, they create a shadow zone on the opposite side of the Earth from the epicentre.
- Anisotropy in the upper mantle was inferred from the observed splitting of the S wave into two distinct polarisations.
Learning
Memory Aids
Mnemonic
S wave = Secondary & Shear: It comes Second and makes the ground Shake from side to side.
Conceptual Metaphor
The Earth ringing like a bell that has been struck; the S wave is the deeper, slower vibration.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Direct translation 'S-волна' is correct and used. However, confusing it with 'surface wave' (поверхностная волна) is a potential error. Ensure the concept of 'shear' (сдвиг) is understood.
Common Mistakes
- Writing 's-wave' in lowercase.
- Using 'S wave' to refer to any seismic wave, not specifically the shear/secondary body wave.
- Pronouncing it as the letter 'S' (/ɛs/) followed by 'wave', not as one unit.
- Assuming it travels through all states of matter (it does not travel through liquids).
Practice
Quiz
Which of the following is a defining characteristic of an S wave?
FAQ
Frequently Asked Questions
It stands for 'Secondary' (because it arrives after the P wave) and 'Shear' (describing its motion).
No. S waves are shear waves, which require material to have shear strength. Liquids like water cannot support shear stress, so S waves cannot propagate through them.
S waves have larger amplitudes and move the ground in a shearing, side-to-side or up-and-down motion, which causes more structural damage to buildings than the back-and-forth compression of P waves.
The fact that S waves are blocked by the Earth's liquid outer core (creating an S-wave shadow zone) provided the first definitive evidence for the core's liquid nature and helps seismologists map internal boundaries.