In recent years, the Quetta Valley and surrounding areas have experienced unprecedented levels of subsidence, which has been attributed mainly to groundwater withdrawal. However, this region is also tectonically active and is home to several regional strike-slip faults, including the north–south striking left-lateral Chaman Fault System. Several large earthquakes have occurred recently in this area, including one deadly Mw 6.4 earthquake that struck on 28 October 2008. This study integrated Interferometric Synthetic Aperture Radar (InSAR) results with GPS, gravity, seismic reflection profiles, and earthquake centroid-moment-tensor (CMT) data to identify the impact of tectonic and anthropogenic processes on subsidence and earthquake patterns in this region. To detect and map the spatial-temporal features of the processes that led to the surface deformation, this study used two Synthetic Aperture Radar (SAR) time series, i.e., 15 Phased Array L-band Synthetic Aperture Radar (PALSAR) images acquired by an Advanced Land Observing Satellite (ALOS) from 2006–2011 and 40 Environmental Satellite (ENVISAT) Advanced Synthetic Aperture Radar (ASAR) images spanning 2003–2010. A Small Baseline Subset (SBAS) technique was used to investigate surface deformation. Five seismic lines totaling ~60 km, acquired in 2003, were used to map the blind thrust faults beneath a Quaternary alluvium layer. The median filtered SBAS-InSAR average velocity profile supports groundwater withdrawal as the dominant source of subsidence, with some contribution from tectonic subsidence in the Quetta Valley. Results of SBAS-InSAR multi-temporal analysis provide a better explanation for the pre-, co-, and post-seismic displacement pattern caused by the 2008 earthquake swarms across two strike-slip faults.

The foreland fold-and-thrust belt of northern Pakistan is located at the western end of the Himalayan arc, where salt tectonics is responsible for structural styles, hydrocarbon source areas and seismicity. Three sub-regions of fold-and-thrust belt are the Potwar Plateau-Salt Range, Kohat Plateau-Surghar Range and the Bannu BasinKhisor Range. The difference in deformation intensity between these regions is mainly attributed to the presence, or absence, of an Infra-Cambrian salt layer. This study investigates the active tectonics of the Potwar Plateau and Salt Range region, emphasizing the role of salt, using the Small Baseline Subset Interferometry (SBAS) technique and 2-D seismic interpretations. Ten PALSAR images and four seismic profiles from western Potwar Plateau-Salt Range region were used. SBAS results, derived from PALSAR images spanning from 2007 to 2010, suggest that the Potwar Plateau-Salt Range is active with the western portion of the region experiencing an uplift at an average rate of around 10 mm/year. Two uplift anomalies were observed, which were interpreted as zones of transpression and salt diapirism. Time-migrated seismic profiles show that the salt layer acts as a detachment. Our results show that salt has different roles in different regions of the fold-and-thrust belt; in the Potwar Plateau region the salt layer acts as a detachment, while in Salt Range salt flow-induced structures are prominent. The integration of SBAS and 2D seismic interpretation reveals that the deformation of western Potwar Plateau-Salt Range is influenced by two main faults, the dextral Kalabagh fault and the Main Frontal Thrust. Finally, this work was compared to the Kuqa fold-and-thrust belt in western China due to their structural similarities.

Synthetic Aperture Radar (SAR) is a potential application of remote sensing to geological and hydrometeorological hazards. This paper presents sustainability strategies for smart cities: the use of SAR Sentinel-1 for monitoring flood inundation and landslide hazards in Aceh Province, Indonesia. In this study, for flood detection, we attempt to uses Sentinel-1A (S-1A) in the same direction and acquisition through polarization of Vertical transmit and Vertical received (VV) – Vertical transmit and Horizontal received (VH) with a temporal baseline of 6 days. Those data were then analysed using the SNAP Toolbox. The results showed that the S-1A was successfully for detecting a flood inundation in which VH polarization is more sensitive than VV. For landslide monitoring, we apply multitemporal SAR images, where one of them is the Quasi-Persistent Scatterers (Q-PS) technique. Using ascending and descending orbit pass results in a better velocity map where both sides of the slope are detected due to the different sensor angle of both orbital passes. This technique has resulted in the undulating areas being monitored well and this will also fill the gap of layover and shadowing phenomena of the slant range SAR image. The Q-PS combinations were very effective to identify the deformation features associated with the land movement. For a smart city, natural hazards such as landslides and floods require continuous monitoring to ensure the potential as well as management and mitigation of natural hazards. Therefore, the InSAR technique is one of the effective ways for doing this strategy.

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