In the near future hyperspectral spaceborne systems will be available providing spectral data with the potential to enhance exploration and mining activities by remote sensing techniques. In that context, new or enhanced methods are required by the industries to address their needs for new hyperspectral applications. Therefore, large volume of hyperspectral data from selected deposits in the Northern Cape South Africa was acquired during an airborne survey in July/August 2015. These data were used to describe spectroscopically mineral deposits and their mineralogical/geological set. Hyperspectral data of different deposits were collected such as from a lead, zinc and copper deposit associated with the meta sediments region of Aggeneys, iron and asbestos deposit linked with the Banded Iron Formations (BIF) around Prieska and iron / manganese deposit bound to a conglomeratic reworked BIF deposit near Postmasburg. The data were acquired by three sensors to cover the visible light, the near infrared and shortwave infrared (VNIR-SWIR) and the long wave infrared (LWIR) with a spatial resolution of 2.5 m. In addition LIDAR data were acquired to create surface and terrain models with a spatial resolution of 1 m. The preprocessing of the individual flight lines included a radiometric correction, an orthorectification and an atmospheric correction using Atcor4. The temperature emissivity separation of the LWIR data was based on the emissivity normalization method. In a first step mineral maps were created separately in VNIR-SWIR and LWIR by a multi feature extraction approach combined with a spectral unmixing approach based on a constrained least squares method to derive the dominant mineral components per pixel. In a second step the results of the VNIR-SWIR and LWIR mineral mapping were cross validated where applicable. A third step was the synergetic information extraction from the spectral derived mineral paragenesis by a context driven assessment of the mineral distribution and a correlation with the geological setting to characterize and identify mineral deposits. The result shows that the mineralization zone of the lead zinc deposit as well as quartz and hematite correlations in the Banded Iron Formation rocks of the hematite/manganese deposit near Postmasburg are detected. All results are discussed in the context of the mineral system and its geology.

The Iberian Pyrite Belt in the south of Portugal and Spain is one of the world’s largest polymetallic massive sulphide complexes with originally >1700 Mt of massive sulphides, which have been extensively mined in the past. The massive sulphides are hosted by a Volcano-Sedimentary-Complex formed in a basinal facies during the Variscan orogeny. Recently, new exploration activities including core drilling to a depth of several hundreds of meter have taken place in Los Frailes (Spain) to evaluate the potential of underground mining in this area. Because the regional mining potential is still existing, especially regarding deeper ore bodies, new application-oriented methods for mineral prospection and exploration combining surface and subsurface information need to be developed. Satellite multispectral and field-based hyperspectral remote sensing data were acquired which provide mineralogical surface information due to mineral-diagnostic absorption features in the solar-reflective spectral range (VNIR-SWIR). The distribution of natural radioactivity (K, Th, U), derived from data of airborne gamma-ray spectroscopy, reveal mineral alteration patterns of the (near-)surface. As the near-surface ore bodies are nearly exhausted, airborne SQUID-based gradient magnetometry data were recorded for subsurface information (up to max. 200 m depth) which show structures that are linked to faults and bodies of magnetic rock.
Imaging and point spectroscopy were performed in the open pit of Los Frailes and on a 580 m drill core taken in this area with the aisaFENIX and ASD FieldSpec4 Hi-Res, respectively. Around the ore body, a typical inner chlorite-rich and a peripheral muscovite-rich hydrothermal alteration zone as well as an enrichment of Fe in these minerals were detected using linear spectral unmixing and multi-feature extraction. Because airborne and/or satellite hyperspectral imagery of this area is not yet available, the potential for mineral mapping of commercial high-resolution WorldView-3 imagery (VNIR-SWIR) acquired in May 2018 over open-pit areas in Aznalcóllar-Los Frailes and Tharsis is evaluated and discussed in the geological and mineralogical context. The airborne radiometric data show a good distinction between the different lithologies of the Iberian Pyrite Belt. The distribution of K in the hydrothermal alteration zones can be used for distinguishing chlorite-rich and muscovite-rich rocks which can be confirmed by the results of the hyperspectral analysis in Los Frailes. The vertical component of the gradient magnetometry data show several weak magnetic anomalies in the study areas which could not always be linked to known geological structures. Therefore, prominent anomalies were investigated in the field. The magnetic anomaly southeast of Tharsis correlates with a chlorite-rich and a surrounding muscovite-rich zone detected with the point spectrometer ASD FieldSpec4 Hi-Res. These results can indicate the presence of a blind ore body.
The combination of remote sensing and geophysical techniques shows the potential of the contribution to mineral deposit prospection by using the data synergistically to define new exploration targets.

Ahora Gorge is a 400m deep canyon located along the NE flank of Mt. Ararat (Turkey), a compound volcanic complex covered by an ice cap. In the past, several diarists and scientific authors reported a calamitous event in July 2, 1840, when a landslide triggered by a volcanic eruption or an earthquake erased several villages located at the foot of the volcano. The reasons and effects of this Ahora Gorge Catastrophe (AGC) event have been obscure and ambiguous. To reappraise the 1840 catastrophe and the geomorphic evolution of the Ahora Gorge, we used high-resolution satellite images, remote sense thermal data and observations collected during two field surveys. In particular we used high-resolution Pleiades and SPOT images and medium- resolution Sentinel and Landsat 8 data.
According to our interpretation, an earthquake in 1840 triggered an abrupt volcanic emission, which caused the consequent rapid melting of glacial ice and mountain snow. This event produced significant mud and ice flow along the Ahora Gorge inundating the villages downslope. The flooding, which we interpret as a lahar, built a wide alluvial fan at the foot of the volcano. Today, an elongated landform present within the Ahora Gorge has alternately been interpreted as a landslide deposit. Our integrated analysis and ground-based observations demonstrate that this landform is an unmapped glacier. The shape of the landform coupled with ASTER thermal satellite data and ground-based observations reveal that a debris-covered glacier (DCG) formed soon after the catastrophic lahar. Our discovery of the Ahora Gorge Glacier in context of a reappraisal of the Ahora Gorge Catastrophe highlights the contribution of glaciers in shaping the landscape near ice-capped volcanoes. Moreover, our data underscore the importance of being more aware of the potential future geo-hazards posed by Mount Ararat, particularly where glaciers are still present along several valleys and seismically-induced lahar events might occur.

We use optical satellite data to map the co-seismic displacements of the Mw=7.5 strike-slip earthquake of 28 September 2018 in Palu, Sulawesi, Indonesia. This was a strike-slip faulting event at shallow depth that occurred within the interior of the Molucca Sea microplate, which is part of the Sunda tectonic plate. The earthquake was followed by a localised tsunami that struck the city of Palu, sweeping shore-lying houses and buildings on its way. The combined effects of the earthquake and tsunami led to the deaths of at least 2000 people. We applied optical image correlation on Sentinel-2 and Planet imagery, in order to map the surface rupture extent of the earthquake and to extract the co-seismic offsets. Before- and after- the earthquake image acquisitions were analyzed using MicMac software and the MPIC-OPT service on the ESA Geohazards TEP platform. Multiple Sentinel-2 frames, using different dates pre- and post-earthquake, were combined in order to map the total extent of the fault rupture, while Planet images enabled a finer resolution for a 20 km part of the rupture inside the Palu alluvial valley.
Our results include the mapping of tectonic deformation, namely: a) the detailed rupture trace of the left-lateral fault at the southern part of the region (Palu segment) and b) a more complex deformation pattern at the northern part of the rupture. Moreover, analysis of the horizontal displacement field and sequential profiles across the fault also enabled mapping of the fault zone complexity, secondary faulting, fault zone damage/width and large co-seismic gravitational phenomena. A mean horizontal displacement ranging from 3-5 metres was extracted for a total rupture length of more than 140 km. Our results agree with the focal mechanism solution for the earthquake which indicates that the rupture occurred on a left-lateral, north-south striking fault. The kinematics of this event is also associated with the severity of the tsunami impact. Further investigation is necessary to determine the source of the tsunami as primarily tectonic or due to another mechanism although a more complex mechanism is likely.
Acknowledgement: We acknowledge support of this research by the project ‘‘HELPOS—Hellenic System for Lithosphere Monitoring’’ (MIS 5002697).

DInSAR deformation rate measurements support a wide range of applications in the field of geology, geophysics and geo-hazards. The inherent differential nature of the interferometric measurements and the additive delays like troposphere and ionosphere make the accuracy of such measurements strongly dependent on the distance. That means that large scale processes like tectonic movements can be observed with lower accuracy than small scale phenomena like urban subsidence or infrastructure monitoring. However it has been shown [1] that external correction of atmosphere and other geodetic effects can strongly improve the potential accuracy achieving the goal of σ=1 mm/year even at several hundreds of kilometres and with a reduced time series length. Nonetheless the integration with GPS measurements provides a calibration of the interferometric data:
- further reducing the atmospheric residuals on the final results
- removing dependency on the reference point
In this work a calibration strategy based on the knowledge of the measurement uncertainties is presented. Given a deformation rate map estimated using DInSAR and a set of GPS displacement rates on the same area the difference between Line of Sight projected GPS displacements and the deformation rates map is computed. For every GPS station an offset w.r.t. DInSAR results is then available. The mean value of this offset represents the motion of the reference point not included in interferometric measurements. The residuals w.r.t. this offset represent on the other side a further calibration screen that can be applied to the deformation rates. However this information is sampled on the GPS stations’ grid. Knowing the DInSAR as well as GPSs uncertainties, it is now possible to perform a covariance-based interpolation of the offsets in order to compute a calibration screen to be removed from the interferometric data. Spatial covariance of the atmospheric residuals of DInSAR data can be computed as in [1] analysing the variograms of the interferograms formed with a short temporal baseline. The variograms are averaged in order to derive a covariance matrix of the GPS/DInSAR offsets C_atmo. The clutter related noise of the interferometric measurements and the GPS uncertainties contribute with a diagonal to the offset covariance matrix σ_clut^2 I ,σ_(GPS,LoS)^2 I . For every point of the DInSAR map is possible to compute a calibration constant linearly combining the GPS/DInSAR offsets with coefficients a that can be computed as:

a=( (σ_clut)^2 I + (σ_(GPS,LoS))^2 I + C_atmo )^(-1) r

where r represents the vector of the covariance values between the given point and the input offsets. The methodology has been first tested on simulated examples and then implemented on real data scenario. For the study two Sentinel 1-A/B stacks covering the north part of Holland have been used. The stacks have been corrected for troposphere using ECMWF ERA-5 data and processed using PSInSAR technique. No spatial high pass filtering or polynomial de-trending has been applied on the final data. The GPS data used for the study are available on Nevada Geodetic Laboratories webpage (geodesy.unr.edu) [2]. The above described technique has been applied on both results. Figures show the final calibration of the two results in comparison to the original processing, and the position of the GPS stations used in the combination.

[1] F. Rodriguez Gonzalez, A. Parizzi and R. Brcic, "Evaluating the impact of geodetic corrections on interferometric deformation measurements," EUSAR 2018; 12th European Conference on Synthetic Aperture Radar, Aachen, Germany, 2018, pp. 1-5
[2] Blewitt, G., C. Kreemer, W.C. Hammond, and J. Gazeaux (2016). MIDAS robust trend estimator for accurate GPS station velocities without step detection, Journal of Geophysical Research, 121, doi:10.1002/2015JB012552

The European Plate Observing System (EPOS) is a long-term plan to foster and facilitate the integrated use of data, products, software and services available from distributed Research Infrastructures (RI) in Europe in the field of Solid Earth Science (SES). EPOS is a pan-European Research Infrastructure of the ESFRI Roadmap; EPOS has recently become a European Research Infrastructure Consortium (ERIC) hosted by INGV in Italy and supported by 25 European countries and several international organizations.
EPOS integrates a large number of existing European RIs belonging to several fields of Solid Earth Science, from seismology to geodesy, near fault and volcanic observatories as well as anthropogenic hazards and satellite observations. In the EPOS vision there is the integration of the existing national and trans-national research infrastructures that will increase the access and use of the multidisciplinary data recorded by the solid Earth monitoring networks, acquired in laboratory experiments and/or produced by computational simulations. The establishment of EPOS will foster the interoperability of products and services in the Earth science field to a worldwide community of users. Accordingly, EPOS aims at integrating the diverse and advanced European Research Infrastructures in the field of Solid Earth Science and building on new e-science opportunities to monitor and understand the dynamic and complex Solid Earth System.
One of the EPOS Thematic Core Services (TCS), referred to as Satellite Data (SATD), aims at developing, implementing and deploying advanced satellite data products and services, mainly based on Copernicus data (namely Sentinel acquisitions), suitable to be largely used by the SES community.
This work intends to present the technological enhancements and the activities carried out to implement the TCS SATD and to deploy effective satellite services in a harmonized and integrated way. In particular, EPOS has recently concluded the validation process and is going to enter, in 2019, in the pre-operations phase. The TCS Satellite Data has successfully passed the internal and external validation processes and will deploy, in the pre-operations phase, three services (EPOSAR, GDM, COMET) developed to generate advanced Differential Synthetic Aperture Radar (SAR) Interferometry (DInSAR) products, such as interferograms, deformation maps, deformation time series, and velocity maps, based on the exploitation of Sentinel-1 data. These services can work in two different operative scenarios: systematic processing and on-demand processing. In the first case, the satellite products are automatically generated on specific and defined areas when new satellite acquisitions are available; the users can discover the available products directly in the EPOS central hub and download or integrate them with other EPOS products (GPS measurements, geological information, seismological observations, etc.). In the second case, the users can benefit from advanced web-tools made available by the TCS to process the DInSAR datasets of interest. With the on-demand services, the users exploit, through user-friendly interfaces, the availability, in the same environment, of SAR archives, Earth Observation tools, and Cloud Computing resources.
The TCS SATD is integrated within the EPOS infrastructure through a common and harmonized interface that allows service providers and users to search, process, implement and share satellite images, results and processing tools. Such gateway of the TCS SATD is represented by the ESA Geohazards Exploitation Platform (GEP), a new cloud-based platform for satellite Earth Observations, designed to support the scientific community in the understanding of high impact natural disasters. TCS Satellite Data will use GEP as common interface of the TCS toward the EPOS portal to benefit from community-recognized data and metadata formats and standards as well as machine-to-machine protocols. Moreover GEP can host the TCS SATD on-demand processing tools that can be easily implemented in the advanced cloud-based environment provided by GEP, thus allowing users to gather and process on a cloud-computing infrastructure large DInSAR datasets without any need to download them locally and install desktop applications.
In addition to the abovementioned three DInSAR services (EPOSAR, GDM, COMET), TCS SATD is also working on value-added tools and services able to provide synoptic information on the Earth surface displacements, their source mechanisms and their impacts. In particular, 3D-Def and MOD services, together with EPOSAR and COMET, will distribute source models, 3D displacement maps, and seismic hazard maps derived from satellite products both on-demand and in a systematic and continuous way. These latter services integrate satellite measurements, in situ observations and modelling techniques to extract information on the source mechanisms that have generated the surface deformation phenomena and to provide a synoptic view of the investigated phenomena. The implementation and integration within the EPOS infrastructure of the value-added services is on going and they will be released during 2019.
Finally, all the products and results provided by the TCS SATD observe the FAIR principles. In particular, they are findable, accessible, interoperable and reusable, since the TCS uses formats and standard accepted by the community (e.g., ISO 19119, GEOTIFF, ASCII) and guarantees the open and free access to its products and results by applying CC-by and CC-by-NC licences.