We applied the Small Baseline Subset multi-temporal InSAR technique (SBAS) to two SAR datasets acquired from 2003 up to 2013 by Envisat (ESA, European Space Agency) and COSMO-SkyMed (ASI, Italian Space Agency) satellites to investigate spatial and temporal patterns of land subsidence in the Sibari Plain (Southern Italy). Subsidence processes (up to ~20 mm/yr) were investigated comparing geological, hydrogeological, and land use information with interferometric results. We suppose a correlation between subsidence and thickness of the Plio-Quaternary succession suggesting an active role of the isostatic compensation. Furthermore, the active back thrusting in the Corigliano Gulf could trigger a flexural subsidence mechanism even if fault activity and earthquakes do not seem play a role in the present subsidence. In this context, the compaction of Holocene deposits contributes to ground deformation. Despite the rapid urbanization of the area in the last 50 years, we do not consider the intensive groundwater pumping and related water table drop as the main triggering cause of subsidence phenomena, in disagreement with some previous publications. Our interpretation for the deformation fields related to natural and anthropogenic factors would be a comprehensive and exhaustive justification to the complexity of subsidence processes in the Sibari Plain.
In this work, we map surficial ground deformations that occurred during the years 2004–2010 in the Crati Valley (Southern Italy). The valley is in one of the most seismically active regions of the Italian peninsula, and presents slope instability and widespread landslide phenomena. We measured ground deformations by applying the small baseline subset (SBAS) technique, a multi-temporal synthetic aperture radar interferometry (InSAR) methodology that is used to process datasets of synthetic aperture radar (SAR) images. Ground displacements are only partially visible with the InSAR technique. Visibility depends on the geometry of the acquisition layout, such as the radar acquisition angle view, and the land use. These two factors determine the backscattering of the reflected signal. Most of the ground deformation detected by InSAR can be attributed to the gravitational mass movements of the hillslopes (i.e., landslides), and the subsidence of the quaternary deposits filling the valley. The movements observed along the valley slopes were compared with the available landslide catalog. We also identified another cause of movement in this area, i.e., ground subsidence due to the compaction of the quaternary deposits filling the valley. This compaction can be ascribed to various sources, such as urban population growth and sprawl, industrial water withdrawal, and tectonic activity.
6 December 2022 in Science of The Total Environment
The Erosion Potential Method is a model for qualifying the erosion severity and estimating the total annual sediment yield of a catchment. The method includes a diverse set of equations, which are influenced by different factors such as geology, morphology, climate and soil use. This study describes a PyQGIS YES plug-in, which allows a semiautomatized use of the Erosion Potential Method in Geographic Information System (GIS) environment. In detail, we developed a plug-in using Python programming language that is made up of a series of operations allowing one to estimate sediment production through a wizard procedure. The first stage consists of data preprocessing and involves: (i) loading of the layers (e.g., geological map); (ii) spatial selection of the catchment area; (iii) elaboration of loaded layers (e.g., clipping). During the second stage, the user assigns a relative coefficient to each factor either by selecting a preloaded value from bibliographic sources or by inserting a value inferred from field observations and data. The third stage includes the addition of rainfall and temperature values loaded as: average values, point shapefiles (the plug-in calculates the average monthly values) or tables (the plug-in creates the linear regression depending on altitude). During the final stage, the plug-in executes the equation of EPM Model obtaining the sediment yield value at basin scale. Additionally, the user can use the “squared cell” method choosing the appropriate option in the setting dialogue of the plug-in. This method divides the catchment area in a regularly-spaced grid which allows one to carry out the distribution map of the sediment production during the final stage.
Sea state knowledge has a key role in evaluation of coastal erosion, the assessment of vulnerability and potential in coastal zone utilization, and development of numerical models to predict its evolution. X-band radar measurements were conducted to observe the spatial and temporal variation of the sea-state parameters along a 3km long sandy-gravelly pocket beaches forming a littoral cell on Bagnara Calabra. We produced a sequence of 1000 images of the sea state extending offshore up to 1 mile. The survey has allowed monitoring the coastline, the directional wave spectra, the sea surface current fields, and the significant wave heights and detecting strong rip currents which cause scours around the open inlets and affect the stability of the submerged reef-type breakwaters. The possibility to validate the data acquired with other datasets (e.g., LaMMA Consortium) demonstrates the potential of the X-band radar technology as a monitoring tool to advance the understanding of the linkages between sea conditions, nearshore sediment dynamics, and coastal change. This work proves the possibility to obtain relevant information (e.g., wave number, period, and direction) for evaluation of local erosion phenomena and of morphological changes in the nearshore and surf zone. Sea state knowledge has a key role in evaluation of coastal erosion, the assessment of vulnerability and potential in coastal zone utilization, and development of numerical models to predict its evolution. X-band radar measurements were conducted to observe the spatial and temporal variation of the sea-state parameters along a 3km long sandy-gravelly pocket beaches forming a littoral cell on Bagnara Calabra. We produced a sequence of 1000 images of the sea state extending offshore up to 1 mile. The survey has allowed monitoring the coastline, the directional wave spectra, the sea surface current fields, and the significant wave heights and detecting strong rip currents which cause scours around the open inlets and affect the stability of the submerged reef-type breakwaters. The possibility to validate the data acquired with other datasets (e.g., LaMMA Consortium) demonstrates the potential of the X-band radar technology as a monitoring tool to advance the understanding of the linkages between sea conditions, nearshore sediment dynamics, and coastal change. This work proves the possibility to obtain relevant information (e.g., wave number, period, and direction) for evaluation of local erosion phenomena and of morphological changes in the nearshore and surf zone.