Long-Distance 3D Reconstructions Using Photogrammetry with Curiosity’s ChemCam Remote Micro-Imager in Gale Crater (Mars)

The Mars Science Laboratory rover Curiosity landed in Gale crater (Mars) in August 2012. It has since been studying the lower part of the 5 km-high sedimentary pile that composes Gale’s central mound, Aeolis Mons. To assess the sedimentary record, the MSL team mainly uses a suite of imagers onboard the rover, providing various pixel sizes and fields of view from close to long-range observations. For this latter, we notably use the Remote Micro Imager (RMI), a subsystem of the ChemCam instrument that acts as 700 mm-focal length telescope, providing the smallest angular pixel size of the set of cameras on the Remote Sensing Mast. The RMI allows observations of remote outcrops up to a few kilometers away from the rover. As retrieving 3D information is critical to characterize the structures of the sedimentary deposits, we describe in this work an experiment aiming at computing for the first time with RMI Digital Outcrop Models of these distant outcrops. We show that Structure-from-Motion photogrammetry can successfully be applied to suitable sets of individual RMI frames to reconstruct the 3D shape and relief of these distant outcrops. These results show that a dedicated set of observations can be envisaged to characterize the most interesting geological features surrounding the rover.

Utilization of Digital Mapping and Outcrop Model to Assess Reservoir Characterization and Quality Index: Study Case from Ngrayong Formation in the Randugunting Block, East Java

Digital mapping and digital outcrop modeling are the current state of the art in geology that incorporated traditional field geological mapping and digital technique. Integration of these two techniques produce a realistic earth model that could help to understand its petroleum prospectivity. Our study aims to provide a workflow and illustrate preliminary reservoir characterization as well as reservoir quality index assessment from mapping and digital outcrop model in the area with lack of subsurface dataset, such as limited well and seismic data distribution due to an early exploration stage. We utilized a mix siliciclastic-carbonate outcrop of Ngrayong formation in the Randugunting Block, East Java, collecting several measuring sections and followed by rock sampling per certain interval. Drone acquisition was implemented in the area of interest to generate high resolution 3D outcrop model. The measuring section later on tied with digital outcrop model, producing structural and stratigraphic model. In addition, subsurface reservoir parameters from well and seismic were integrated in order to add accuracy value to our model from surface perspective. Facies and properties model were populated and Reservoir Quality Index (RQI) was calculated to suggest any potential flow units. Our results show excellent alignment between structural, facies, properties model and reservoir quality index to illustrate characteristic of reservoir in the study area. Uncertainty comes from geostatistical approach, data acquisition quality, and theoritical assumption where multiple sensitivity analyses were conducted to optimize the model. Methodology presented in this study can help to assess the reservoir characterization and quality index in the early exploration stage. Thus, reservoir distribution, potential flow units and petroleum prospectivity will be mostly predictable. In addition, this study has successfully visualized and manifested preliminary 3D subsurface reservoir characterization in area with lack of subsurface dataset and reduced significant capital expenditure cost (CAPEX) for acquisition new data on early exploration phase.

An algorithm for the 3D ROck Slope Kinematic Analysis (ROKA) based on RPAS digital photogrammetry data.

<p>Among the several adopted methods for the kinematic analysis of the possible modes of failure that could affect a rock slope, the Markland test is the most used. Whereas, it has the advantage of being simple and fast, it has some limits, as the impossibility to manually consider the several different slope orientations and their interaction with the discontinuity dimensions and positions.</p><p>Recently, the improvements in the Remote Piloted Aerial System (RPAS) digital photogrammetry techniques for the development and mapping of Digital Outcrop Models (DOMs) have given the possibility of developing new automatized digital approaches. In this study, ROKA (ROck slope Kinematic Analysis) algorithm is presented. It is an open-source algorithm, written in MATLAB language, which aims to perform the kinematic analysis of the stability of a rock slope using the discontinuity measurements collected onto 3D DOMs. Its main advantage is the possibility to identify the possible critical combination between the 3D georeferenced discontinuities and the local surface of the slope. In particular, the critical combinations that can activate the planar sliding, flexural toppling, wedge sliding and direct toppling modes of failures can be detected and highlighted directly on the DOM. Hence, the ROKA algorithm can make the traditional approach for the kinematic analysis of a rock slope more effective, allowing not only to simplify the analysis, but also to increase its detail. This can be very important, in particular, for the analysis of large and complex rock slopes.</p>

3D Digital Outcrop Model analysis of fracture networks: insights from the Mt. Vettore Fault Zone.

<p>In the last years, several studies investigated the Mt. Vettore Fault Zone (MVFZ), activated during the 2016 Central Italy seismic sequence. Research has focused mainly on aftershocks and mainshock locations, coseismic slip and surface cracks, while an accurate study of the fracture network in the MVFZ was never conducted.</p><p>In this study we present a fracture analysis performed using very high resolution (0.5 – 5 cm) Digital Outcrop Models (DOMs) that developed by Unmanned Aerial Vehicle (UAV)-based digital photogrammetry. The UAV gave the possibility to investigate outcrops with dimensions up to hundreds of metres high and wide, and acquire big and precise fracture data using 3D digital automatic and manual mapping techniques. To investigate the structural variability of the MVFZ fracture network, we realized several DOMs located in different positions, along and around the major fault. All the selected outcrops are formed by Calcare Massiccio Fm., which better records brittle deformation in the study area.</p><p>This analysis aimed to better understand the MVFZ fracture network, including mechanics, kinematics and local structural evolution. In particular, it allowed to determine: 1) the main sets of fractures; 2) the geometrical parameters of the fracture network (e.g. fracture density, persistence, roughness and aperture); 3) the relative timing of the main tectonic brittle events. The preliminary analysis of the DOMs suggests a variability of the fracture network parameters over the MVFZ, especially for what concerned fracture set orientation and density. </p><p> </p><p> </p>

High-resolution Sampling and Photogrammetry of the Permian-Triassic Boundary Within the Festningen Profile, Svalbard

<p>The Permian period ended with a mass extinction event about 252 million years ago. A likely trigger of the mass extinction was the eruption of large volumes of magma which had moved through the Tunguska Basin in Siberia. The renowned Festningen section in the outer part of Isfjorden, western Spitsbergen, offers a c. 7 km long nearly continuous stratigraphic section of Lower Carboniferous to Cenozoic strata, where the end-Permian extinction interval is well-exposed. Tectonic deformation associated with the Paleogene West Spitsbergen fold-and-thrust-belt tilted the strata to near-vertical, allowing easy access along the shoreline. The section is a regionally important stratigraphic reference profile and is a key locality for geologists visiting Svalbard. The main objective of our fieldwork in September 2020 was to collect closely spaced mudstone (0.25 to 1 m interval) and ash layer (6 layers of 0.5 to 1.5 cm thickness) samples across the Festningen Permian-Triassic boundary for chemostratigraphic and geochronological assessments. Carbon isotope data reveal a well-defined negative deltaC13 excursion in the lower part of the Vardebukta Fm. Zircons are present in most of the ash layer samples and these will be dated at the University of Oslo TIMS U-Pb Isotope Geology Laboratory. In this contribution, we will also present a new digital outcrop model of the P-Tr boundary section acquired using a UAV (Mavic 2 Pro, 20MP Hasselblad camera). During acquisition, the maximum drone speed was set to 1 meter/second (i.e., “tripod mode”), and photographs were taken automatically at set time intervals (e.g., 1 photo every 5 seconds ≈ meters). The digital outcrop model offers a pixel resolution of 7.27 mm/pixel. The Festningen model will be available online through the Svalbox.no geoscience data platform.</p>

APLIKASI FOTOGRAMETRI PADA REKAHAN ALAMI BATUAN DASAR GRANITIK DAERAH MUARO SILOKEK, SUMATERA BARAT

<p class="Abstract">Daerah penelitian berlokasi di Sungai Indragiti, Daerah Muaro Silokek, Kabupaten Sijunjung, Provinsi Sumatera Barat. Tujuan ini digunakan untuk mengetahui orientasi rekahan alami dari data <em>Digital Outcrop Model (DOM)</em>. Pengambilan data <em>Digital Outcrop Model (DOM)</em> menggunakan metode fotogrametri menggunakan drone, untuk menganalisis rekahan alami dengan skala makro. Interpretasi rekahan pada <em>Digital Outcrop Model (DOM)</em> digunakan untuk mengetahui domain struktur pada daerah penelitian. Hasil interpretasi rekahan alami, terdapat tiga domain struktur yang memiliki orientasi utara baratlaut-selatan tenggara, selatan timurlaut-barat baratdaya, dan timurlaut-baratdaya. Domain struktur yang terbentuk merupakan rekahan yang terbentuk akibat sesar mendatar menganan yang berorientasi tenggara-baratlaut berdasarkan sistem riedel.</p>

An Open-Source Algorithm for 3D ROck Slope Kinematic Analysis (ROKA)

The Markland test is one of the most diffused and adopted methods of kinematic analysis for the identification of critical intersections of rock discontinuities that could generate rock failures. Traditionally, the kinematic analysis is based on the use of a stereographic approach that is able to identify the critical combination between the orientations of discontinuities and the rock wall. The recent improvements in the use of Digital Outcrop Models (DOMs) created the conditions for the development of a new automatized approach. We present ROck Slope Kinematic Analysis (ROKA) which is an open-source algorithm aimed at performing the Kinematic Analysis using the discontinuity measures collected onto a 3D DOM. The presented algorithm is able to make a local identification of the possible critical combination between the identified discontinuities and the orientation of the slope. Using this approach, the algorithm is able to identify on the slope the presence of critical combinations according to the traditional kinematic analysis of planar failure, flexural toppling, wedge failure, and direct toppling modes of failures and then visualize them on DOMs. In this way, the traditional approach is more effective and can be adopted for a more detailed analysis of large and complex areas.