Carolina Guardiola-Albert

Mathematics of Planet Earth

1. Advances in classical statistics relevant to the geosciences.- 2. Frontier statistics.- 3. Compositional data analysis applied to geochemistry.- 4. Data assimilation in geosciences.- 5. Machine learning in geoscience applications.- 6. Spatiotemporal analysis: structural complexity and extreme behaviour. -7. Parameterization of soil systems at different scales.- 8. Fractals, chaos and complexity in the earth system.- 9. Remote sensing a changing world.- 10 Radar remote sensing for the detection, monitoring and modelling of ground instabilities.- 11. Geographic information systems/geoinformatics.- 12. Quantitative methods in geomorphology and land surface processes.- 13. Deformation modelling, geodynamics and natural hazards.- 14. Hydrogeology: From process understanding to improved predictions. - 15. Quantitative hydrology: working across scientific disciplines and time space scales.- 16. Quantitative environmental geology.- 17. Modelling of energy resources.- 18. New developments in oil and gas discovery modelling.- 19. Open session on mathematics of oil recovery.- 20 Geostatistical priors in inversion of geophysical and engineering data.- 21 Mineral and energy resources for planet earth: Evaluation, extraction and optimal management.- 22 Recent advances in quantitative methods applied to stratigraphy and paleontology.- 23 Geo-mathematical models of folds and folding.- 24. Mathematical geosciences and planetary geology.- 25. Mathematics of planet earth.- 26 Geoscience data models for practical interoperability. -27. Advances on stochastic non linear methods and inverse problems for dynamic models.

Interpolation of GPS and Geological Data Using InSAR Deformation Maps: Method and Application to Land Subsidence in the Alto Guadalentín Aquifer (SE Spain)

Land subsidence resulting from groundwater extractions is a global phenomenon adversely affecting many regions worldwide. Understanding the governing processes and mitigating associated hazards require knowing the spatial distribution of the implicated factors (piezometric levels, lithology, ground deformation), usually only known at discrete locations. Here, we propose a methodology based on the Kriging with External Drift (KED) approach to interpolate sparse point measurements of variables influencing land subsidence using high density InSAR measurements. In our study, located in the Alto Guadalentin basin, SE Spain, these variables are GPS vertical velocities and the thickness of compressible soils. First, we estimate InSAR and GPS rates of subsidence covering the periods 2003–2010 and 2004–2013, respectively. Then, we apply the KED method to the discrete variables. The resulting continuous GPS velocity map shows maximum subsidence rates of 13 cm/year in the center of the basin, in agreement with previous studies. The compressible deposits thickness map is significantly improved. We also test the coherence of Sentinel-1 data in the study region and evaluate the applicability of this methodology with the new satellite, which will improve the monitoring of aquifer-related subsidence and the mapping of variables governing this phenomenon.

Comparison of Recharge Estimation Methods During a Wet Period in a Karst Aquifer

Management of water resources, implying their appropriate protection, calls for a sound evaluation of recharge. Such assessment is very complex in karst aquifers. Most methods are developed for application to detrital aquifers, without taking into account the extraordinary heterogeneity of porosity and permeability of karst systems. It is commonly recommended to estimate recharge using multiple methods; however, differences inherent to the diverse methods make it difficult to clarify the accuracy of each result. In this study, recharge was estimated in a karst aquifer working in a natural regime, in a Mediterranean-type climate, in the western part of the Sierra de las Nieves (southern Spain). Mediterranean climate regions are characterized by high inter-annual rainfall variability featuring long dry periods and short intense wet periods, the latter constituting the most important contribution to aquifer water input. This paper aims to identify the methods that provide the most plausible range of recharge rate during wet periods. Six methods were tested: the classical method of Thornthwaite-Mather, the Visual Balan code, the chloride balance method, and spatially distributed methods such as APLIS, a novel spatiotemporal estimation of recharge, and ZOODRM. The results help determine valid methods for application in the rest of the unit of study and in similar karst aquifers.

Karst massif susceptibility from rock matrix, fracture and conduit porosities: a case study of the Sierra de las Nieves (Málaga, Spain)

The potential contamination of a karst massif from surface sources can be evaluated and represented in a susceptibility map. In the case of a carbonate aquifer, the susceptibility assessment must take into account their very complex and heterogeneous nature. The complexity originates in the presence of three types of porosity: matrix rock, fracture and conduit porosity. This paper presents a method for karst susceptibility mapping by estimating the three porosity types and evaluates their integration in a single susceptibility index. Matrix rock porosity is measured in the laboratory from samples collected in the field and is well correlated with lithology. Fracture porosity is estimated from fracture mapping and field measurements of secondary fracture porosity. Geostatistical methods are used to obtain continuous fields of rock matrix porosity and fracture porosity. Conduit porosity is calculated from a power model fitted to speleological cave mapping data. However, because of the scarcity and sampling bias of conduit data, probabilistic models are conjectured. A fourth porosity factor evaluated is the detritic filling of karst depressions. The integration of the different porosities in a single susceptibility factor gives a quantitative map that is reclassified to provide a qualitative, easy to interpret susceptibility index map of the karst system. Porosity estimation may also be of interest in recharge estimation and mathematical modelling of flow and transport in karst systems. The case study used to illustrate this approach is the Sierra de las Nieves karstified rock mass, a high relief Mediterranean karst in the province of Málaga in southern Spain.

Groundwater and Subsidence Modeling Combining Geological and Multi-Satellite SAR Data over the Alto Guadalentín Aquifer (SE Spain)

In the current context of climate change, improving groundwater monitoring and management is an important issue for human communities in arid environments. The exploitation of groundwater resources can trigger land subsidence producing damage in urban structures and infrastructures. Alto Guadalentin aquifer system in SE Spain has been exploited since 1960 producing an average piezometric level drop of 150 m. This work presents a groundwater model that reproduces groundwater evolution during 52 years with an average error below 10%. The geometry of the model was improved introducing a layer of less permeable and deformable soft soils derived from InSAR deformation and borehole data. The resulting aquifer system history of the piezometric level has been compared with ENVISAT deformation data to calculate a first-order relationship between groundwater changes, soft soil thickness, and surface deformation. This relationship has been validated with the displacement data from ERS and Cosmo-SkyMed satellites. The resulting regression function is then used as an empirical subsidence model to estimate a first approximation of the deformation of the aquifer system since the beginning of the groundwater extraction, reaching 1 to 5.5 m in 52 years. These rough estimations highlight the limitations of the proposed empirical model, requiring the implementation of a coupled hydrogeomechanical model.

A Method for Automatic Detection and Delineation of Karst Depressions and Hills

Karst depressions of decametric scale (dolines, uvalas, poljes, and other endorheic basins) play an important role in the hydrogeology of karst aquifers. They are traps of sediment and when their detritic filling has an important thickness they can retain a large amount of water delaying their percolation towards the water table or towards the networks of conduits. Many times the delineation of the depressions may be difficult because the study area may be very large, or inaccessible or hidden by vegetation. In those circumstances, it is of great help to have an automatic method of depression detection and delineation. The proposed procedure uses the digital elevation model, a geographical information system, an algorithm of pit removal and basic operations of map algebra. The method provides the depth of each detected depression measured from its rim. This fact can be used to detect the center of maximum depth as well as for calculating morphometric parameters using depth. The final map of depressions can be characterized by altitude in order to have morphometric parameters related with elevation. The algorithm has been extended for detection and delineation of karst hills. The methodology is illustrated with the Sierra de las Nieves karst aquifer in the province of Malaga, Southern Spain, where the depressions and hills show a strong structural control.

Integral Porosity Estimation of the Sierra de Las Nieves Karst Aquifer (Málaga, Spain)

Karst aquifers are very complex and heterogeneous systems because of the presence of three kinds of porosity (matrix rock porosity, fracture porosity, and conduit porosity) that generally have a large spatial variability. In order to have realistic karst models the three kinds of porosity and their spatial variability must be taken into account. A quantitative model of a karst aquifer is proposed by integration of the three kinds of porosity in a three dimensional numeric model. Nevertheless, the main task of this work is restricted to the proposal of methods for their evaluation. Matrix rock porosity has been measured in the laboratory from samples collected in the field. Matrix rock porosity is well correlated with the lithology and with the structural position of the rock. Fracture porosity has been estimated from fracture mapping and field measurements. A geostatistical method is used to obtain a continuous field of fracture porosity. Conduit porosity has been calculated from a power model fitted to speleologic cave mapping data. However, because of the scarcity of conduit data, probabilistic models must be conjectured. The integration of the three kinds of porosity gives a three dimensional numerical model that can be used in vulnerability mapping, recharge estimation, and mathematical modeling of flow and transport in karst systems. The approach is illustrated with the Sierra de las Nieves karst aquifer in the province of Malaga in Southern Spain.

SlugIn 1.0: A Free Tool for Automated Slug Test Analysis: S. Martos-Rosillo et al. Groundwater xx, no. x: x-xx

The correct characterization of aquifer parameters is essential for water-supply and water-quality investigations. Slug tests are widely used for these purposes. While free software is available to interpret slug tests, some codes are not user-friendly, or do not include a wide range of methods to interpret the results, or do not include automatic, inverse solutions to the test data. The private sector has also generated several good programs to interpret slug test data, but they are not free of charge. The computer program SlugIn 1.0 is available online for free download, and is demonstrated to aid in the analysis of slug tests to estimate hydraulic parameters. The program provides an easy-to-use Graphical User Interface. SlugIn 1.0 incorporates automated parameter estimation and facilitates the visualization of several interpretations of the same test. It incorporates solutions for confined and unconfined aquifers, partially penetrating wells, skin effects, shape factor, anisotropy, high hydraulic conductivity formations and the Mace test for large-diameter wells. It is available in English and Spanish and can be downloaded from the web site of the Geological Survey of Spain. Two field examples are presented to illustrate how the software operates.

Numerical Karst: Spatio-Temporal Modelling of Karst Aquifer Systems

The quantitative study of karst aquifers is of great interest due to their enormous importance as water resources and their environmental impact on both the surface and underground. Most attempts to model karst systems use black box models where a transfer function of the system is estimated based on the statistical relationship between input time series (rainfall) and output time series (spring discharge). These models consider the karst system as a whole and do not provide distributed spatial information of the system. In this paper, a methodology called numerical karst is proposed for spatio-temporal modelling of karst systems. The hierarchy of the karst flow system is recognized and three types of flow are considered: vertical flow through the vadose zone, channel and pipe flow inside the karst conduit network system and flow in the saturated zone. The modelling involves several steps: conceptual karst modelling, spatio-temporal recharge evaluation, simulation of a conduit network, soil-epikarst assessment and mapping and mathematical modelling of all of the flow processes. An inverse procedure is used for model calibration, using daily spatially distributed discharge values. The methodology is tested in the Sierra de las Nieves aquifer, a high relief karst system located in Malaga province, Southern Spain.

Geostatistical Analysis of PSI Radar Data: A Methodology to Assess Serviceable Limit State of Buildings

A new methodology to assess serviceability limit state of buildings is presented. It is based on the geostatistical analysis of advanced radar interferometry (PSI) results. This methodology has been tested in the historical buildings of Orihuela City (SE Spain), damaged during the last two decades due to ground subsidence caused by aquifer overexploitation. Results demonstrate that the proposed PSI post-processing methodology can be a cost effective tool to rapidly identify potential problematic buildings and infrastructures in urban areas where forensic analysis should be made.