Remote Detection of Geothermal Alteration Using Airborne Light Detection and Ranging Return Intensity

The remote detection of hydrothermally altered grounds in geothermal exploration demands datasets capable of reliably detecting key outcrops with fine spatial resolution. While optical thermal or radar-based datasets have resolution limitations, airborne LiDAR offers point-based detection through its LiDAR return intensity (LRI) values, serving as a proxy for surface reflectivity. Despite this potential, few studies have explored LRI value variations in the context of hydrothermal alteration and their utility in distinguishing altered from unaltered rocks. Although the link between alteration degree and LRI values has been established under laboratory conditions, this relationship has yet to be demonstrated in airborne data. This study investigates the applicability of laboratory results to airborne LRI data for alteration detection. Utilising LRI datafrom an airborne LiDAR point cloud (wavelength 1064 nm, density 12 points per square metre) acquired over a prospective geothermal area in Bajawa, Indonesia, where rock sampling for a related laboratory study took place, we compare the airborne LRI values within each ground sampling area of a 3 m radius (due to hand-held GPS uncertainty) with laboratory LRI values of corresponding rock samples. Our findings reveal distinguishable differences between strongly altered and unaltered samples, with LRI discrepancies of approximately ~28 for airborne data and ~12 for laboratory data. Furthermore, the relative trends of airborne and laboratory-based LRI data concerning alteration degree exhibit striking similarity. These consistent results for alteration degree in laboratory and airborne data mark a significant step towards LRI-based alteration mapping from airborne platforms

The Deep Sea and Sub-Seafloor Frontier

The deep sea and its sub-seafloor contain a vast reservoir of physical, mineral and biological resources that are rapidly coming into the window of exploitation. Assessing the opportunities and the risks involved requires a serious commitment to excellent deep sea research. There are numerous areas in this field in which Europe has cutting-edge technological potential. These include drilling and monitoring technology in the field of renewable energies such as geothermal, offshore wind and seafloor resources. Scientific ocean drilling will continue to play a valuable role, for example in the exploration of resource opportunities, in obtaining estimates for ecosystem and Earth climate sensitivity, or in improving understanding about the controlling factors governing processes and recurrence intervals of submarine geohazards. In Europe, there is also the scientific expertise needed to define a framework for policymakers for environmental protection measures and to carry out ecological impact assessments before, during and after commercial exploitation. Taking up these societal challenges will strengthen European scientific and educational networks and promote the development of world-class technology and industrial leadership.Published3.7. Dinamica del clima e dell'oceano4.6. Oceanografia operativa per la valutazione dei rischi in aree marineope

The Argyre Region as a Prime Target for in situ Astrobiological Exploration of Mars

At the time before ∼3.5 Ga that life originated and began to spread on Earth, Mars was a wetter and more geologically dynamic planet than it is today. The Argyre basin, in the southern cratered highlands of Mars, formed from a giant impact at ∼3.93 Ga, which generated an enormous basin approximately 1800 km in diameter. The early post-impact environment of the Argyre basin possibly contained many of the ingredients that are thought to be necessary for life: abundant and long-lived liquid water, biogenic elements, and energy sources, all of which would have supported a regional environment favorable for the origin and the persistence of life. We discuss the astrobiological significance of some landscape features and terrain types in the Argyre region that are promising and accessible sites for astrobiological exploration. These include (i) deposits related to the hydrothermal activity associated with the Argyre impact event, subsequent impacts, and those associated with the migration of heated water along Argyre-induced basement structures; (ii) constructs along the floor of the basin that could mark venting of volatiles, possibly related to the development of mud volcanoes; (iii) features interpreted as ice-cored mounds (open-system pingos), whose origin and development could be the result of deeply seated groundwater upwelling to the surface; (iv) sedimentary deposits related to the formation of glaciers along the basin's margins, such as evidenced by the ridges interpreted to be eskers on the basin floor; (v) sedimentary deposits related to the formation of lakes in both the primary Argyre basin and other smaller impact-derived basins along the margin, including those in the highly degraded rim materials; and (vi) crater-wall gullies, whose morphology points to a structural origin and discharge of (wet) flows

Reconstruction of the 2018 Anak Krakatau collapse using PlanetScope imaging and numerical modeling

The study was focused on the Anak Krakatau sector collapse that occurred on 22 December 2018 in the Sunda Strait (Indonesia). The goal of the study was to monitor and analyze changes of the volcanic edifice and to try to understand causes that may have predisposed and triggered the sector collapse. The use of different remote sensing techniques allowed the acquisition of thermal data, SO2 emission data, structural data and the identification and analysis of the eruptive events that occurred on Anak Krakatau in the period from 1° January 2016 to 28 February 2019. The acquisition of 1221 thermal data and 1156 SO2 emission data was performed using MODIS and OMI. Anak Krakatau began a new and intense activity phase on 30 June 2018 which continued in the following six months preceding the lateral collapse of the SW flank of the volcanic edifice, reaching its climax in September. The activity subsequently followed a decreasing trend, ending shortly after the collapse. The thermal data and the use of PlanetScope images allowed the identification of 8 lava flows, 7 of which developed between July and November 2018, exactly in the months that preceded the collapse. Almost all the lava flows affected the SW, S-SW and S slopes of the volcanic cone. These events led to an increase of the lithostatic load on the area subsequently collapsed. Precisely, their volume is equal to 6.8x106 m3. The volumes of all the lava flows were calculated considering an average thickness of 10m, obtaining a total volume equal to 8.2x106 m3. Further analysis of the satellite images highlighted a shift of the summit crater mainly towards the area subsequently collapsed and the generation of different curvilinear fractures which can be grouped in three main strikes’ groups: NW-SE; E-W and NNE-SSW. The structures with NW-SE strike agree with regional tectonics while those with E-W and NNE-SSW direction delimit the subsequent collapse. What has been observed indicates that there were precursory signs of structural instability. Finally, based on the collected data, bibliographic information regarding the extent of caldera-forming ignimbrite and deep surveys, it was possible to create the first pre-collapse 3D model representing the area present before the 2018 collapse. This model is a key element for a possible simulation of the sector collapse that occurred on Anak Krakatau. The model allows to test three hypotheses of possible predisposing causes in future studies: 1) Increase of the lithostatic load on the SW side of the volcano generated by the deposition of all products erupted during the last phase of activity, considering also its high inclination (\u3e 20 °); 2) Dike intrusion into the shallow portion of the volcanic edifice; 3) External factors which are common predisposing causes that influence the stability of the volcanic slopes such as a failure plane, zones of weakness, hydrothermal activity and mechanical weakening by alteration. The study shows that the collapse of Anak Krakatau could have been anticipated through continuous monitoring of the volcano and its activity using different remote sensing techniques. Finally, we believe that the combination of 3D models, representing areas with signs of instability, and remote sensing techniques is an important method for predicting potentially disastrous events, and Anak Krakatau is an example

Past, Present and Future of a Habitable Earth

This perspective of this book views Earth's various layers as a whole system, and tries to understand how to achieve harmony and sustainable development between human society and nature, with the theme of " habitability of the Earth." This book is one effort at providing an overview of some of the recent exciting advances Chinese geoscientists have made. It is the concerted team effort of a group of researchers from diverse backgrounds to generalize their vision for Earth science in the next 10 years. The book is intended for scholars, administrators of the Science and Technology policy department, and science research funding agencies. This is an open access book