GLOSSARY OF SEISMIC TECHNICAL TERMS

 

Wave Terms

Body  Wave  – Seismic  waves  within  the earth.
Longitudinal  Wave  -  Pure  compressional wave with volume changes. 
Love Wave – Surface waves that produce a sideways motion.

Rayleigh Wave - Forward and elliptical vertical seismic surface waves. 
P-Wave - The primary or fastest  waves traveling away from a seismic event through the earth's crust, and consisting of a train of compressions and dilatations of the material(push and pull).

S-Wave - Shear wave, produced essentially by the shearing or tearing motions of earthquakes at right angles to the direction of wave propagation. 
Seismic Surface Wave - A seismic wave that follows the earth's surface only, with a speed less than that of S-waves. 

 

Seismic Engineering Terms

SHM – structural health monitoring

PSA - 5% damped elastic pseudo-obsolete acceleration response spectral ordinates
Response spectra
Design Codes or building codes, like EC, NEHRP or DIN codes.
    - NEHRP - National Earthquake Hazards Reduction Program
    - EC - Eurocode
    - DIN - Deutsches Institut für Normung
PGA - peak ground accelleration
PGV - peak ground velocity
PGD - peak ground displacement

Fundamental Frequency - ...

 

Seismic Terms

Moment Tensor - Moment tensors provide a general theoretical framework to describe seismic sources based on generalized force couples

RSAM - Real-time Seismic-Amplitude Measurement- presents the overall signal size over
periods of 10 minutes. In situations when the number of earthquakes is so high that individual earthquakes can't be seen, or the level of volcanic tremor is such that seismograms no longer show a change in signal level, then RSAM is an excellent way of showing changes with time.
SSAM -  stands for Seismic Spectral-Amplitude Measurement. It shows the relative signal size in different frequency bands. Using SSAM it is possible to get an idea of whether a signal is produced by earthquakes, by wind or traffic noise, or by volcanic tremor. Earthquakes, wind and traffic noise all tend to have energy at a wide range of frequencies (a wide-band signal), while volcanic tremor tends to have energy in a more limited range of frequencies (a narrow-band signal).

Tsunami Terms

Tsunamigenic - Is an term for an EQ which can trigger an tsunami.

Bathymetry - is the study of underwater depth of lake or ocean floors.

Topography - is the study of the shape and features of the surface of the Earth

Inundation - A inundation is an overflow of water that submerges land that is usually dry.

Run Up - Is the level of the tsunami wave on the coast.

Travel Time - The time the tsunami wave need to travel from the EQ source to the coast.

Seismic Hardware

Digitizer

    - Q330 - Quanterra 330 - Datasheet - Documentation