Geohazards and ground motion
The ground moves before it fails. InSAR keeps the ledger.
The ground moves a millimetre. Satellites notice before engineers do.Continental-scale InSAR ground motion mapping
Persistent Scatterer and Small Baseline InSAR techniques convert years of Sentinel-1 radar imagery into millimetre-per-year velocity fields across entire nations, giving geological surveys and infrastructure owners a systematic picture of where the ground is rising or sinking.
Sentinel-1 (IW mode)ALOS-2 PALSAR-2EGMS derived products
The ground moves millimetres per year. The next earthquake moves metres.Interseismic strain accumulation on active faults
Between earthquakes, locked fault segments store elastic strain that will eventually release violently. InSAR time series and GNSS networks can measure this slow accumulation and constrain where slip deficits are growing.
Sentinel-1 (C-band SAR, ESA)ALOS-2 PALSAR-2 (L-band SAR, JAXA)GNSS/GPS continuous networks
The fault moves metres in seconds. The satellite sees every centimetre.Coseismic surface displacement mapping after earthquakes
SAR interferometry and pixel-offset tracking can map coseismic surface rupture, fault geometry, and slip distribution within hours to days of a major earthquake, feeding both source-model inversions and emergency damage assessment.
Sentinel-1 A/B (C-band SAR, ESA)ALOS-2 PALSAR-2 (L-band SAR, JAXA)COSMO-SkyMed (X-band SAR, ASI/Italian MoD)
Magma moves centimetres. InSAR sees millimetres.Volcano inflation and deflation monitoring by InSAR
Interferometric SAR detects ground swelling and subsidence above magmatic and hydrothermal systems with millimetre-scale sensitivity, giving volcanologists a continuous geodetic record that precedes eruptions by days to years.
Sentinel-1 A/B (C-band SAR)COSMO-SkyMed 1–4 / Second Generation (X-band SAR)ALOS-2 PALSAR-2 (L-band SAR)
The slope moves centimetres before it moves kilometres.Pre-failure landslide precursor motion detection
Slow creep on an unstable slope can precede catastrophic failure by months or years. InSAR time-series methods detect that creep at millimetre-per-year sensitivity, giving engineers and civil authorities a measurable warning window.
Sentinel-1 A/B (C-band SAR)ALOS-2 PALSAR-2 (L-band SAR)COSMO-SkyMed (X-band SAR)
The ground moves faster than C-band can follow. Choose your wavelength.Mining-induced subsidence and void migration monitoring
Underground longwall coal and hard-rock mining can drop the surface by metres in weeks. Satellite InSAR and offset-tracking methods, chosen to match deformation rate and geology, turn that motion into regulatory-grade displacement maps.
Sentinel-1 A/B (C-band SAR)ALOS-2 PALSAR-2 (L-band SAR)COSMO-SkyMed (X-band SAR)
The ground gives way in seconds. The warning takes months to read.Urban sinkhole and karst subsidence detection
Sinkholes over dissolving limestone, gypsum and salt can swallow roads in moments, yet PS-InSAR reveals the slow bowl-shaped precursor deformation that precedes collapse. Satellite radar is a risk-screening tool, not a real-time alarm.
Sentinel-1 (C-band SAR, ESA)TerraSAR-X / TanDEM-X (X-band SAR, DLR/Airbus)COSMO-SkyMed (X-band SAR, ASI)
The ground heaves in winter and sinks forever in summer.Permafrost thaw settlement and active-layer dynamics
InSAR time series over permafrost terrain separates reversible seasonal frost heave from irreversible thermokarst subsidence, revealing where ground ice is being lost for good. Rates, extents, and the sensor trade-offs that determine what you can actually measure.
ALOS-2 PALSAR-2 (L-band, 1.27 GHz)Sentinel-1 A/B (C-band, 5.405 GHz)TerraSAR-X / TanDEM-X (X-band, 9.65 GHz)
Cliffs retreat a metre at a time. Satellites catch every step.Coastal cliff and shoreline erosion rate measurement
Soft-rock cliffs can lose metres in a single storm. Repeat satellite SAR, very-high-resolution optical imagery, and photogrammetric change detection now make sub-annual recession budgets tractable without a single site visit.
Sentinel-1 SAR (C-band, ESA)Sentinel-2 MSI (ESA)Planet SuperDove
Water fills a reservoir. The crust underneath does not stay still.Reservoir-induced seismicity and dam-body deformation monitoring
InSAR can detect millimetre-scale deformation of dam bodies and surrounding bedrock before that motion becomes a seismic or structural event. This page explains the physics, the sensors, and the honest limits of the method.
Sentinel-1 (C-band SAR, ESA)COSMO-SkyMed (X-band SAR, ASI)TerraSAR-X / TanDEM-X (X-band SAR, DLR)
The fault is there. The question is whether you can measure it.Active tectonic plate boundary and fault mapping from SAR and optical
SAR backscatter, interferometric coherence, and high-resolution stereo DEMs let geologists trace active fault lines and fold scarps from orbit, even where field access is impossible. Resolution limits are real but quantifiable.
TanDEM-XSRTMSentinel-1 SAR
The ground is sinking. The pumping records rarely say how fast.Land subsidence from groundwater and hydrocarbon extraction
InSAR time series from Sentinel-1 and decades of ERS/Envisat archive data can measure broad subsidence bowls caused by aquifer compaction and hydrocarbon withdrawal at millimetre-per-year precision, giving regulators the attribution evidence that piezometers alone cannot provide.
Sentinel-1 A/B (C-band SAR)ERS-1/2 and Envisat ASAR (C-band SAR, archive)ALOS-2 PALSAR-2 (L-band SAR)
Fluids move underground. The surface cannot hide it.Geothermal field surface deformation and resource monitoring
InSAR tracks millimetre-scale uplift and subsidence at geothermal fields caused by injection, extraction, and thermally driven pressure changes. Published work at Reykjanes, Wairakei, and The Geysers shows how Sentinel-1 and TerraSAR-X time series reveal reservoir behaviour that wellhead sensors alone cannot capture.
Sentinel-1 (C-band SAR, ESA)TerraSAR-X (X-band SAR, DLR / Airbus)COSMO-SkyMed (X-band SAR, ASI)
The rock does not lie. The image interpreter sometimes does.Structural geological mapping for mineral and hydrocarbon exploration
Multispectral, hyperspectral, and SAR imagery can reveal lithological contacts, alteration halos, and structural lineaments across terrain that would take years to map on foot. The method is powerful and genuinely cost-reducing, but ambiguity between tectonic and non-tectonic features demands disciplined ground-truth before exploration capital is committed.
ASTER (Terra)Sentinel-2 MSISentinel-1 SAR (C-band)
The fault moves. No earthquake. Satellites notice anyway.Slow slip event detection on subduction zones
Slow slip events release tectonic stress aseismically over days to months, producing surface displacements too small for seismometers but resolvable by InSAR time-series and GNSS. This page covers the physics, the processing chains, and the public datasets that have documented SSEs on Cascadia, Hikurangi and Guerrero.
Sentinel-1 A/B (ESA)ALOS-2 PALSAR-2 (JAXA)COMET LiCSAR (NERC/COMET)
The fault stops rupturing. The ground keeps moving for decades.Postseismic viscoelastic relaxation and afterslip mapping
After large earthquakes, the crust deforms for months to years through afterslip and viscoelastic flow. InSAR time-series from Sentinel-1 and ALOS-2 separate these mechanisms and constrain the rheological models that underpin long-term seismic hazard assessment.
Sentinel-1 A/B (C-band SAR, ESA)ALOS-2 PALSAR-2 (L-band SAR, JAXA)ARIA GUNW (processed Sentinel-1 unwrapped interferograms, NASA/Caltech JPL)
Ice leaves. Rock rises. Separating the two signals is the hard part.Glacial isostatic adjustment and ice-unloading uplift measurement
As ice sheets shed mass, the mantle rebounds upward at millimetres to centimetres per year. Sentinel-1 InSAR stacking and continuous GNSS now resolve that signal, but disentangling ancient GIA from present-day elastic rebound demands careful modelling.
Sentinel-1 A/B (C-band SAR)TanDEM-X (X-band SAR)Continuous GNSS (SONEL / UNAVCO networks)
Salt moves slowly. The surface above it does not lie.Salt diapir rise and dissolution subsidence at surface
Active salt diapirs produce domal uplift or dissolution-driven subsidence bowls measurable by InSAR at sub-millimetre precision. Sentinel-1 and ERS archive data reveal halokinetic rates across the Zechstein basin and Dead Sea region that matter for infrastructure siting and hazard assessment.
Sentinel-1 A/B (C-band SAR, ESA)ERS-1/2 and Envisat ASAR (C-band SAR, ESA archive)COSMO-SkyMed (X-band SAR, ASI)
The ground moves before the crack appears. InSAR catches it first.Surface settlement monitoring above tunnel and metro construction
Mechanised tunnelling creates predictable Gaussian settlement troughs at surface. X-band InSAR tracks these troughs at millimetre precision, flagging deviations from Peck-curve predictions before structural damage reaches buildings or utilities.
TerraSAR-X / TanDEM-XCOSMO-SkyMed (first and second generation)Sentinel-1 A/B
A building tilts millimetres before it cracks centimetres.Differential settlement and tilt monitoring of individual buildings
Persistent Scatterer InSAR resolves line-of-sight displacement on individual buildings to sub-millimetre precision, detecting differential settlement weeks or months before visible structural damage appears. This page explains the method, its real limits, and what published studies in Mexico City, Shanghai and Rotterdam have demonstrated.
TerraSAR-X / TanDEM-XSentinel-1 A/BCOSMO-SkyMed (first and second generation)
Trains run on millimetres. InSAR measures them from orbit.Railway embankment and trackbed deformation from InSAR
Persistent Scatterer InSAR detects sub-centimetre settlement along railway embankments, correlating deformation with load cycles and groundwater. Published UK and Italian programmes show it works at scale.
Sentinel-1 A/B (C-band SAR, ESA)TerraSAR-X / TanDEM-X (X-band SAR, DLR/Airbus)COSMO-SkyMed (X-band SAR, ASI/Italian MoD)
Peat breathes with the water table. InSAR can hear it.Peatland surface oscillation and carbon-stock change detection
Intact peatlands oscillate vertically by several centimetres each season; drained ones subside irreversibly. InSAR time-series turns millimetre-scale surface motion into a proxy for water-table depth, carbon storage and degradation risk.
Sentinel-1 A/B (C-band, 5.6 cm wavelength)ALOS-2 PALSAR-2 (L-band, 23.6 cm wavelength)Envisat ASAR (C-band archive, 2002-2010)
Deltas sink faster than the sea rises. The gap is measurable.River delta sediment compaction and relative sea-level rise
Major river deltas subside at rates that dwarf global mean sea-level rise, driven by sediment compaction, fluid withdrawal and starved fluvial supply. InSAR from Sentinel-1 and ALOS-2 quantifies these rates at millimetre-per-year precision, and combined with tide-gauge records, yields the relative sea-level rise figure that coastal planners actually need.
Sentinel-1 A/B (C-band SAR, ESA)ALOS-2 PALSAR-2 (L-band SAR, JAXA)Envisat ASAR archive (C-band SAR, ESA)
The ice lifts off its bed. InSAR sees exactly where.Ice sheet grounding line migration and basal melt detection
The grounding line separating grounded ice from floating ice shelf shifts as ocean heat melts ice from below. Differential InSAR captures the tidal flexure zone that marks this boundary, revealing retreat rates on glaciers like Thwaites and Pine Island.
Sentinel-1 A/B (C-band SAR, ESA)ERS-1/2 Tandem Mission archive (C-band SAR, ESA)Envisat ASAR (C-band SAR, ESA)
Ice moves too fast for InSAR. Physics still leaves a trail.Glacier surge and rapid flow velocity mapping by SAR offset tracking
Surging glaciers can accelerate from metres to kilometres per year in weeks, breaking conventional InSAR. SAR amplitude offset tracking and multiple-aperture InSAR recover full 2-D velocity fields where phase-based methods fail entirely.
Sentinel-1 A/C (C-band SAR, ESA)ALOS-2 PALSAR-2 (L-band SAR, JAXA)Landsat 8/9 OLI (optical, USGS/NASA)
The ice is invisible. The creep is not.Rock glacier creep rate and permafrost ice content estimation
Rock glaciers move centimetres to metres per year, and that velocity encodes permafrost temperature and ice content. InSAR and SAR offset tracking on Sentinel-1 and ALOS-2 PALSAR-2 turn surface motion into a structural and thermal proxy.
Sentinel-1 A/B (C-band SAR, ESA)ALOS-2 PALSAR-2 (L-band SAR, JAXA)TerraSAR-X / TanDEM-X (X-band SAR, Airbus/DLR)
The ground moves millimetres. The liability moves billions.Oil and gas field surface deformation from reservoir pressure change
Production-induced pore-pressure changes compact or rebound reservoir rocks, producing surface signals detectable by InSAR at millimetre precision. Sentinel-1 and archival ERS/Envisat data let operators quantify compressibility, anticipate casing damage, and assess induced-seismicity exposure before regulators do.
Sentinel-1 A/B (C-band SAR, ESA)Envisat ASAR (C-band SAR, ESA archive)ERS-1/2 (C-band SAR, ESA archive)
CO2 stays underground. The ground above it does not stay still.CO2 geological storage site surface uplift monitoring
Injecting supercritical CO2 into deep formations raises pore pressure and lifts the surface by millimetres to centimetres. InSAR time-series turn that motion into an independent mass-balance check and a regulatory compliance record.
Sentinel-1 A/B (C-band SAR, ESA)TerraSAR-X / TanDEM-X (X-band SAR, DLR)Envisat ASAR (C-band SAR, ESA, archived)
Injection wells cannot hide what they do to the crust beneath them.Induced seismicity risk from wastewater injection and InSAR precursors
Deep disposal of oilfield wastewater raises pore pressure on pre-existing faults, triggering earthquakes. Sentinel-1 InSAR time-series can detect millimetre-scale surface deformation that precedes or accompanies these events, constraining fault geometry and causal injection volumes.
Sentinel-1 A/B (C-band SAR, ESA)ALOS-2 PALSAR-2 (L-band SAR, JAXA)COSMO-SkyMed (X-band SAR, ASI)
The slope has failed. Now measure exactly what moved where.Post-failure landslide runout and deposit volume mapping
DEM differencing between pre- and post-event elevation models quantifies landslide deposit volume and runout geometry within days of failure, directly informing dam-break and downstream flood risk. This page covers the methodology, co-registration error budgets, and published results from the 2017 Maoxian and 2018 Baige events.
TanDEM-X bistatic DEMCopernicus DEM GLO-30Pléiades 1A/1B stereo
The fault moves silently. The radar notices every millimetre.Aseismic fault creep rate measurement on strike-slip faults
Some fault segments slip continuously without earthquakes, accumulating or relieving seismic moment deficit. InSAR time-series over ERS, Envisat and Sentinel-1 archives resolves surface creep rates to sub-millimetre per year precision, constraining where the next locked patch begins.
Sentinel-1 A/B (C-band SAR, ESA)ERS-1/2 and Envisat ASAR (C-band SAR, ESA archive)ALOS-2 PALSAR-2 (L-band SAR, JAXA)
Lakes appear in decades. They can vanish in days.Thermokarst lake expansion and drainage in thawing permafrost
Thawing permafrost creates thermokarst lakes that expand laterally for years, then drain catastrophically through ice-wedge breaches. Multitemporal Landsat and Sentinel-1 track area change; InSAR resolves the ground settlement that precedes and follows each event.
Sentinel-1 A/B (C-band SAR, 5.6 cm wavelength)ALOS-2 PALSAR-2 (L-band SAR, 23.6 cm wavelength)Landsat 8 and 9 (OLI/TIRS)
Dunes move. The question is how fast, and toward what.Aeolian sand dune migration rate and sediment flux mapping
Active sand dunes migrate at metres to tens of metres per year, threatening roads, pipelines and farmland. SAR amplitude offset tracking and sub-metre optical feature tracking now make systematic, basin-wide measurement routine.
Sentinel-1 A/B (C-band SAR)Pléiades 1A/1B (optical, sub-metre)COSMO-SkyMed (X-band SAR)
The seabed shifts. Inspection vessels visit once a year.Seabed movement detection above subsea pipelines and cables
Satellite InSAR and photon-counting lidar can detect millimetre-scale onshore settlement and nearshore bathymetric change above subsea corridors between survey campaigns, but both methods have hard depth and turbidity limits that operators must understand before trusting the data.
Sentinel-1 C-band SAR (ESA)ICESat-2 ATL03/ATL07 photon-counting lidar (NASA)TanDEM-X bistatic SAR (DLR)
The ground moves for months before it falls. InSAR sees it.Abandoned shallow mine void and crown-hole collapse risk mapping
Shallow historic mine workings produce millimetre-scale precursor subsidence before crown-hole collapse. Persistent-scatterer and small-baseline InSAR can detect that signal weeks to months in advance, if you choose the right wavelength for the terrain.
Sentinel-1 (C-band SAR, 5.6 cm wavelength)ALOS-2 PALSAR-2 (L-band SAR, 23.6 cm wavelength)COSMO-SkyMed (X-band SAR, 3.1 cm wavelength)
The mountain rises. The river cuts back. Satellites measure both.Rock uplift and fluvial incision rate comparison from satellite geodesy
In active orogens, tectonic uplift and fluvial incision compete at rates of fractions of a millimetre to several millimetres per year. Sentinel-1 InSAR, continuous GNSS, and multi-epoch DEMs from SRTM and TanDEM-X can quantify both sides of that balance, with important caveats about atmospheric noise and erosional ambiguity.
Sentinel-1 (C-band SAR, ESA)TanDEM-X (X-band bistatic SAR, DLR)SRTM (C-band radar, NASA/NGA, 2000)
Ash buries the landscape. The elevation difference tells you how much.Syn-eruption tephra deposit thickness and extent mapping
Pre- and post-eruption DEM differencing and SAR amplitude change let analysts estimate tephra volume and thickness, while SWIR optical bands separate fresh ash from cloud and snow during the eruption window itself.
TanDEM-XSentinel-1 C-band SARSentinel-2 MSI
A slope moves millimetres before it moves tonnes.Highway and road-cut slope instability monitoring by InSAR
Time-series InSAR detects millimetre-scale displacement on road-cut slopes and embankments months before failure. Sentinel-1, COSMO-SkyMed and ALOS-2 PALSAR-2 cover different trade-offs of resolution, revisit and vegetation penetration.
Sentinel-1 A/B (C-band SAR)COSMO-SkyMed Second Generation (X-band SAR, spotlight mode)ALOS-2 PALSAR-2 (L-band SAR)
The earthquake happened ten thousand years ago. The scarp is still there.Fault scarp morphology and palaeoseismic rupture mapping from high-resolution DEMs
High-resolution DEMs from spaceborne lidar and bistatic SAR expose fault scarps, sag ponds and pressure ridges that record prehistoric ruptures, letting geologists estimate slip-per-event and recurrence intervals without a trench.
GEDI (Global Ecosystem Dynamics Investigation, ISS)TanDEM-X (X-band bistatic SAR, DLR/Airbus)ALOS World 3D (AW3D30)
Peat burns underground. The surface tells you how much is gone.Peat fire combustion depth and ground-level loss measurement
Subsurface peat combustion during drought can lower the ground surface by tens of centimetres in weeks. Combining InSAR displacement time-series with VIIRS and MODIS fire radiative power separates combustion-driven loss from seasonal peatland oscillation, though attribution between burning, drainage and post-fire compaction requires field validation.
Sentinel-1 A/B (C-band SAR, ESA)ALOS-2 PALSAR-2 (L-band SAR, JAXA)VIIRS 375 m active fire product (Suomi-NPP / NOAA-20)
The waterline moves. The bank remembers every position it held.Reservoir bank erosion and delta sedimentation from multi-temporal imagery
Cyclically fluctuating reservoir levels expose bank materials to wetting, drying and gravity in patterns that satellite time-series can decode. Sentinel-1 InSAR detects centimetre-scale slumping; Sentinel-2 water indices track the moving shoreline that normalises how long each bank zone was exposed.
Sentinel-1 (C-band SAR, ESA)Sentinel-2 MSI (ESA)Landsat 8/9 OLI (USGS/NASA)
The ground moves every summer. Not every movement is subsidence.Thermal expansion and contraction of urban ground and infrastructure from InSAR
Seasonal and diurnal temperature swings expand concrete and masonry by several millimetres, producing InSAR signals that mimic structural settlement. Separating thermoelastic deformation from genuine subsidence requires careful regression against surface temperature records.
COSMO-SkyMed (X-band SAR)TerraSAR-X / TanDEM-X (X-band SAR)Sentinel-1 (C-band SAR)
Sand moves. Forty years of satellites recorded where it went.Barrier island and beach ridge migration from SAR and optical time-series
Barrier islands and beach ridges shift landward or lengthen laterally over years to decades. Combining Landsat's 40-year archive with Sentinel-1 SAR and sub-10 m optical data makes those shifts measurable, defensible and actionable.
Landsat 4-9Sentinel-2 MSIPlanet SuperDove