Glossary Terms

2 · 3 · 4 · A · B · C · D · F · G · H · L · M · N · O · P · R · S · V · W

2D seismic survey

An exploration method used to create images of structure and stratigraphy beneath the Earth's surface by placing sensors and sources along a single profile.


3D seismic survey

An exploration method used to collect detailed and comprehensive data of the subsurface by placing and recording sensors along multiple lines in a grid format from source lines orthogonal to them.


4D seismic survey

An exploration technique used to identify and monitor time-lapse changes in the subsurface by repeating and comparing a 3D seismic survey (occasionally 2D surveys) over different time intervals.



A sensor used for measuring the acceleration of a moving or vibrating object.

Active shot

The deliberate creation of seismic waves through controlled energy sources such as vibrators, dynamite or thumpers. [If this is purely for land, OK to include air guns if generic]


A signal processing term that describes the misidentification or distortion of frequencies caused by a signal being sampled at an insufficient rate.

Ambient noise

All the noise present in a given environment and can also be referred to as ‘background noise’


Brute stack

A time section formed by stacked common midpoint gathers that have undergone very basic processing. The brute stack is used as a reference to assess the improvement in quality of the data throughout the processing sequence.


CCUS exploration

The process of searching, identifying and assessing potential subsurface locations for carbon capture, use and storage (CCUS) projects.

CCUS monitoring

The procedure of monitoring and assessing the subsurface environment, primarily the movement and storage of carbon dioxide in underground geological formations before, during and after the injection process in CCUS projects.

Compressive sensing

An approach to signal processing which allows signals and images to be built with lower sampling rates and from multidimensions than those required by Nyquist sampling theorem.



To remove or reduce the noise from a signal, an image or other form of data.


A method used in geophysical exploration which transmits seismic waves, generated by controlled explosions, into the ground.


Full production Pre-stack time migration (PSTM)

A computer based method that considers the complex wave propagation effects and time delays in seismic data prior to stacking or processing, providing clarity and improved subsurface imaging capabilities.

Full-wave inversion (FWI)

A high-resolution seismic imaging technique that utilises the full information provided by seismic traces to extract physical parameters of the subsurface that have been sampled by seismic waves.



A type of sensor used in geophysics to detect and measure seismic waves when placed in or on the ground.

Geothermal exploration

The process of searching, identifying and assessing potential subsurface locations for geothermal projects.

Geothermal monitoring

The procedure of monitoring and assessing the subsurface environment, primarily the movement of fluids in underground geological formations before, during and after the production of energy or heat in geothermal projects.


High-trace-density seismic survey

A subjective appellation given to seismic surveys with a significantly increased spatial sampling, this is achieved by increasing the number of receivers or sources on the surface (or both). High trace density seismic (or sometime shortened to High-density seismic) can significantly increase the quality of the subsurface image and seismic attributes.


Land seismic acquisition

The process of collecting seismic data used to record and create images of the Earth’s subsurface using a combination of sensors and active shots.

Land seismic sensor

A device - such as a velocity sensor or accelerometer- that senses and records seismic waves to aid exploration


Micro-electromechanical systems (MEMS)

A miniature device that integrates mechanical and electronic components.


A faint tremor in the Earth's surface caused by human activity or a natural phenomenon.

Mining exploration

The process of searching, identifying and assessing potential subsurface locations of mineral deposits.


Near surface geophysics

The field of using geophysical methods to explore the uppermost section of the Earth’s crust, ranging from a couple of meters to hundreds in depth.


A small seismic instrument that is used to record the vibrations and seismic waves on a subsurface.


Oil and gas exploration

The process of searching and identifying deposits of hydrocarbons - specifically oil and natural gas - in the Earth’s subsurface.


Passive seismic

The detection and measurement of naturally occurring low frequency vibrations and waves in the subsurface, without the requirement of an active energy source such as vibrating plates or explosives.

Piezoelectric sensor

A device that converts physical factors such strain, pressure or acceleration into an electrical charge or voltage which can be measured.

PSDM (Pre-stack depth migration)

Seismic migration is the process by which seismic events are geometrically re-located in either space or time to the location the event occurred in the subsurface rather than the perceived location that it was recorded at the surface. Migration moves dipping reflectors to their true subsurface positions and collapses diffractions,[4] resulting in an image that typically has an increased spatial resolution and resolves areas of complex geology much better than non-migrated images. Pre-stack depth migration is a class of migration algorithms that takes into account the lateral variation of the velocity field and the complex paths taken by the wavefield.

Pseudo-3D seismic

A technique used to create three dimensional images of the subsurface by recording a series of two dimensional sensor profiles (in regular or irregular grids) from multiple, typically, irregular source lines.


Raw shot gather

The collection of raw seismic data (unprocessed) grouped in a source/receiver order as delivered by the seismic recording system.


Seismic data processing

A set of techniques used to transform raw seismic data into a visual map, images or models of the Earth’s subsurface.

Seismic Interferometry

A technique that uses the interference of seismic wave patterns to gain additional information about the subsurface usually without the need of an active source. Interferometry can turn each receiver into a virtual source which can than be processed in similar way to an active source.

Seismic sensor

An instrument used in seismic exploration to detect and measure seismic waves or vibrations of the Earth.

Seismic source

A device that generates seismic energy (typically in the form of seismic waves) into the Earth.

Seismic survey design

The process of planning and organising the design of seismic data acquisition, including selecting optimal acquisition parameters and the layout of the survey in order to meet specific subsurface imaging requirements.

Signal-to-noise ratio

The ratio of the desired energy to the unwanted (or total) energy in a signal. This can be a complex process as it is very difficult to fully separate the signal from the noise, and the definition of noise can vary depending on the context.


Relating to, or something lying below the surface.

Subsurface imaging

The process of creating images of the earth’s structure and stratigraphy, either beneath soil or water, through the use of sensors to record the propagation and reflection of seismic waves from interfaces below the earth’s surface.

Surface wave inversion (SWI)

A geophysical technique that analyses a certain type of seismic waves (surface waves) to capture and gain a greater understanding of the near surface layers.

Survey design

The process of planning and organising a geophysical survey which involves selecting the appropriate geophysical method, technology and setting the optimal survey parameters - seismic source method, sensor density, location, timing.


Velocity model

A geophysical model that assign an estimated wave propagation velocity to each geological feature in the subsurface.


A method used in geophysical exploration which transmits seismic waves, generated by a vibrating mass at various frequencies, into the ground.

Virtual shot

Usually refers to a seismic data that resembles a shot gather but that have been generated using interferometry between a set of receivers recording ambient noise. This processed can convert each receiver into a virtual source (hence the name).


Weight drop or thumper

A technique used in geophysical exploration that generates seismic waves in to the ground by dropping a heavy weight onto a metal plate or hydraulic cushion from several meters.

Wireless seismic sensor

A device used to detect the seismic activity or vibrations of the Earth, without the need for physical connection to another device or central data acquisition system.