Revealing the untold stories of sinkhole land subsidence over the remains of an underground river in tuff soil by Ground Penetrating Radar
Why is this work in the frame?
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
No Canadian affiliation. An affiliation-only frame — the usual design — would never have seen this work. It is one of the works that make the case for inverting the frame.
The three-model screen
all 1,000 screened works →All three models called this out of scope.
Geophysical survey using ground penetrating radar to detect sinkhole subsidence.
This applies ground-penetrating radar to sinkhole detection, not research practice.
Geotechnical GPR study of sinkhole land subsidence; domain engineering.
Abstract
Sinkhole-induced land subsidence poses a critical hazard in urban areas underlain by pyroclastic tuff formations. This study applies a calibrated Ground Penetrating Radar (GPR) method to detect subsurface anomalies in Malang city, Indonesia, where residual underground river flow contributes to stratigraphic instability. Using a 90 MHz GPR OKO AB-90 system, calibrated with a portable Vector Network Analyzer (VNA), dielectric values ranging from 4.3 to 13.6 were obtained across dry tuff, saturated clay, and concrete layers. These values yielded reflection coefficients (R) between −0.023 and 0.035, indicating clear contrasts between restored culverts, suspected new sinkholes, and groundwater zones. GPR imaging revealed subsidence features at depths of 4 – 7 m , with high-density signal zones exceeding 0.85 normalized amplitude units. The signal accuracy was validated via Signal-to-Noise Ratio (SNR) and Normalized Root Mean Square Error (NRMSE), with SNR values above 22 dB and NRMSE values below 0.07, confirming reliable anomaly detection. A regression analysis ( R 2 = 0.64 , p < 0.0001 ) between flood severity and subsidence events further supported the hydrogeological linkage and erosion-driven subsurface instability in pyroclastic terrains. These findings demonstrate that calibrated GPR effectively distinguishes subsurface anomalies in moisture-variable tuff environments. This approach enhances early detection of sinkhole-prone zones and supports urban geohazard mitigation strategies. • GPR delineates subsurface anomalies in sinkhole-prone urban volcanic tuff zones. • VNA calibration improves permittivity accuracy and signal reliability for GPR scans. • SNR > 22 dB and NRMSE < 0.07 confirm high-quality subsurface anomaly detection. • Rainfall and flood recurrence contextualize subsidence vulnerability in urban terrain. • Calibrated GPR offers a replicable method for urban geohazard mapping in tuff areas.
Stored with the screening record, where it is evidence for the labels above.
The record
- Venue
- GEOMATICA
- Topic
- Geophysical Methods and Applications
- Field
- Engineering
- Canadian institutions
- —
- Funders
- Universitas AirlanggaUniversiti Teknologi MARA
- Keywords
- Ground-penetrating radarSinkholeGeohazardSubsidenceHydrogeologyAquiferGroundwaterPiezometerRadar
- Has abstract in OpenAlex
- yes