Applied Geophysics

Applied geophysics employs physical measurements—seismic, electrical, electromagnetic, magnetic and gravitational—to image and characterise the subsurface without direct excavation. Seismic techniques probe elastic wave propagation to reveal layer velocities, anisotropy and discontinuities from shallow depths to the deep mantle. Electrical methods, notably resistivity and induced polarisation, map contrasts in conductivity linked to fluid content, porosity and lithology, while electromagnetic surveys extend these insights to greater depths. Magnetic and gravity measurements delineate density and magnetic susceptibility variations, aiding in structural mapping and resource exploration. Recent advances integrate dense sensor arrays, fibre-optic sensing and ambient-noise interferometry with machine-learning algorithms, yielding unprecedented spatial and temporal resolution. Applications span groundwater and mineral resource assessment, hydrocarbon and geothermal exploration, environmental monitoring, infrastructure planning and seismic hazard evaluation. By combining multi-method datasets, practitioners construct three-dimensional models that inform sustainable management of water, energy and mineral resources and support mitigation of natural and anthropogenic hazards.

Research from Nature Portfolio

Innovations in distributed acoustic sensing have transformed existing fibre-optic cables into seismic arrays capable of centimetre-scale strain monitoring over tens of kilometres. A semi-supervised deep-learning framework has been developed to perform accurate P- and S-phase picking on ultra-dense DAS data, substantially improving earthquake detection performance. Complementary work has demonstrated the feasibility of using long-distance telecommunication cables as continuous seismic sensors: by analysing over a year of fibre-optic acquisitions against co-located seismometers, researchers quantified detection probabilities across a broad magnitude range and introduced spectral analysis of fibre data to probe earthquake dynamics. In a foundational study, broadband strain fields captured along a multi-kilometre subsea telecommunication cable imaged faults and dykes with un-aliased, high-resolution detail, validating the potential for global fibre networks to serve as pervasive seismic arrays for environmental and structural monitoring.

Research from all publishers

A novel framework utilises self-organising maps, k-means clustering and a histogram-based centre-selection algorithm to automate lithofacies identification from well-log data in heterogeneous Quaternary aquifers. This approach efficiently rejects noise and yields continuous estimates of hydraulic conductivity that closely match independent measurements. In another development, regression models link post-saturation electrical resistivity of 36 rock types to density, porosity and uniaxial compressive strength, demonstrating that nondestructive resistivity tests can reliably predict key mechanical parameters for preliminary engineering investigations. A third study integrates flood modelling with geoelectric surveys in a sub-Himalayan river basin to assess how varying inundation scenarios affect shallow aquifer vulnerability: by coupling two-dimensional resistivity profiles with hydrodynamic simulations, researchers identified zones at highest risk of contaminant penetration, informing water-resource management under extreme events.

Applied Geophysics publication trend

The graph below shows the total number of articles in applied geophysics across all publications each year (not limited to Nature Index journals).

Technical terms

Seismic tomography: Imaging method that uses recorded seismic wave travel times and amplitudes to reconstruct three-dimensional velocity variations in the Earth’s interior.

Electrical Resistivity Tomography (ERT): Technique that injects current into the ground and measures potential differences to map subsurface resistivity distributions.

Distributed Acoustic Sensing (DAS): Method that uses backscattered laser pulses in fibre-optic cables to measure ground strain continuously at high spatial density.

Apparent resistivity: Simplified resistivity value inferred under the assumption of a homogeneous half-space, used to locate conductive zones.

Ambient noise interferometry: Approach that cross-correlates background seismic noise recordings to retrieve impulse responses between sensors, enabling imaging without active sources.

References

1. Dynamic strain determination using fibre-optic cables allows imaging of seismological and structural features. Nature Communications (2018).
2. Seismic arrival-time picking on distributed acoustic sensing data using semi-supervised learning. Nature Communications (2023).
3. Seismic monitoring using the telecom fiber network. Communications Earth & Environment (2024).
4. Examining innovative unsupervised learning techniques for automated characterization of complex groundwater systems. Results in Engineering (2024).
5. Prediction of physico-mechanical rock characteristics from electrical resistivity tests. Journal of the Southern African Institute of Mining and Metallurgy (2024).
6. Flood modelling and its impacts on groundwater vulnerability in sub-Himalayan region of Pakistan: integration between HEC-RAS and geophysical techniques. Geomatics Natural Hazards and Risk (2023).
7. Emergence of broadband Rayleigh waves from correlations of the ambient seismic noise. Geophysical Research Letters (2004).