shadow zone
Earthquake waves' blindspot
A shadow zone is an area where something—usually a signal or wave—fails to reach.
In seismology, shadow zones are regions on Earth's surface where seismic waves from an earthquake don't arrive directly because the planet's core bends or blocks them.
The term extends to areas where radio signals, radar, or sound waves are blocked or deflected: The mountains created a shadow zone for FM reception.
Any space screened from detection or influence may be called a shadow zone.
Energy moving through rock
- P-waveLongitudinal seismic wave
- S-waveTransverse seismic vibration
- earthquake detectionIdentifying subterranean ground movement
- epicenterPoint above seismic origin
seismometer · outer core · inner core · earthquake monitoring
Unseen domain or territory
- blind spotArea of blocked perception
- uncharted territoryUnmapped, unexplored area
- no-man's-landUnclaimed disputed territory
- gray areaAmbiguous, ill-defined situation
Rapid temperature-change layer
- bathymetrySubaqueous topographical measurement
- ocean stratificationSea divided by density
Waves combining when meeting
- sound absorptionMaterial capturing audio energy
- hydrophoneSubmersible sound sensor
- depth soundingMeasuring water depth
seismic wave
Energy moving through rock
- P-waveLongitudinal seismic wave
- S-waveTransverse seismic vibration
- earthquake detectionIdentifying subterranean ground movement
epicenter · seismometer · outer core · inner core · earthquake monitoring
hidden realm
Unseen domain or territory
- blind spotArea of blocked perception
- uncharted territoryUnmapped, unexplored area
- no-man's-landUnclaimed disputed territory
thermocline
Rapid temperature-change layer
- bathymetrySubaqueous topographical measurement
- ocean stratificationSea divided by density
wave interference
Waves combining when meeting
- sound absorptionMaterial capturing audio energy
- hydrophoneSubmersible sound sensor
- depth soundingMeasuring water depth
- submarine warfaresubmarine, submarines, torpedo, U-boat, sonar
- radio propagationpropagation, skywave, ionosphere, refraction, diffraction
- borderlandsborderland, borderlands, border, border region, border area
- sonaractive sonar, passive sonar, ping, echolocation, hydrophone
- sonar termsping, echo, contact, bearing, reverberation
- strike zoneinside corner, outside corner, knees, knee high, inside edge