Geoscience Research Research Articles

Downhole Microseismic Monitoring Using Time-Division Multiplexed Fiber-Optic Accelerometer Array

Microseismic monitoring is of importance for several geoscience research aspects and for applications in oil and gas industry. For signals generated by the ultra-weak microseismic events, conventional moving-coil geophone systems have reached their limit in detection sensitivity especially at high frequency range. Here we for the first time present a specially tailored fiber-optic sensing system targeting at downhole microseismic monitoring. The system contains 30 individual interferometric accelerometers and 2 reference sensors, which are time-division multiplexed into a 12-level vector seismic sensor array. The multiplexed accelerometers can achieve ~50 ng/ $\sqrt {\mathrm{Hz}} $ noise equivalent acceleration, which is superior to the commercial available moving-coil geophone systems at frequencies above 200 Hz. The measured sensitivity of the accelerometers can reach ~200 rad/g from 10 Hz to 1 kHz. The dynamic range is above 134 dB over the same frequency range and is higher than its electronic counterpart in the low frequency band. Moreover, the sensors can function properly under the harsh condition of 120 °C temperature and 40 MPa pressure over the 4-hour test duration. The sensor array along with the interrogator has been running uninterruptedly over 3 weeks in a multi-stage hydraulic fracturing stimulation field test. On-site results show that our system can clearly resolve the vector nature of both compressional and shear waves generated by the microseismic events.

UAV-Based Photogrammetry and LiDAR for the Characterization of Ice Morphology Evolution

Ice doline is a particular kind of ice morphology, usually scattered on ice streams which are mostly far from the existing research bases. For this reason, glaciologists rarely have opportunities to document its developments in detail. Satellite observations are too coarse to capture such fine features, whereas unmanned aerial vehicle (UAV)-based structure-from-motion (SfM) and light detection and ranging (LiDAR) technologies have revolutionized geosciences research, especially in less accessed polar regions. We developed two bespoke UAV systems for glaciological investigation and carried out four campaigns during two consecutive Chinese Antarctic expeditions in 2017 and 2018. Founded on manual co-registration and accuracy assessment, a successful application to characterize a doline's spatio-temporal evolution is presented in this article. The overlying weight of surface melting directly triggered the collapse event on Jan 30, 2017 near the Dalk Glacier , and thenthe newborn doline grew for another 8135.6 m $^2$ in area and 280 303.38 m $^3$ in volume by early 2018. The UAV-based results revealed the doline's changes during a year, showing a maximum horizontal extension of 50 m and vertical subsidence of more than 10 m. Furthermore, we evaluate the photogrammetry and LiDAR systems and find the former is cost-effective and time-efficient on a large-scale survey, while the latter enjoys a better capability to characterize ice morphological details. Based on systematic comparisons, other pros and cons of the two techniques are discussed. To achieve the best performance for relevant applications in similar scenarios, we recommend adopting an integrated approach, in which the LiDAR restores the fine features on the basis of extensive SfM coverage.

Relevant and flexible geosurveys: how Geological Survey Ireland is adapting

Abstract Geological Survey Ireland is a division of a government department and has typical origins as a geological survey founded to map the nation's natural resources. In recent years it has changed focus from more traditional geological mapping activities and methods to carrying out major projects of national societal value using, and developing, the latest technology. Programmes include one of the world's largest seabed surveys INFOMAR, a national groundwater mapping and protection programme, and modern geophysical and geochemical mapping under its Tellus programme. In addition the Survey has developed a successful geoscience research programme and a business cluster, Geoscience Ireland. By focusing on stakeholder engagement, effective communication of the value of geoscience and maintaining scientific rigour, geological surveys can be as relevant today as when they were founded.

Coastal Boulder Deposits of the Neogene World: A Synopsis

Modern geoscience research pays significant attention to Quaternary coastal boulder deposits, although the evidence from the earlier geologic periods can be of great importance. The undertaken compilation of the literature permits to indicate 21 articles devoted to such deposits of Neogene age. These are chiefly case studies. Such an insufficiency of investigations may be linked to poor preservation potential of coastal boulder deposits and methodological difficulties. Equal attention has been paid by geoscientists to Miocene and Pliocene deposits. Taking into account the much shorter duration of the Pliocene, an overemphasis of boulders of this age becomes evident. Hypothetically, this can be explained by more favorable conditions for boulder formation, including a larger number of hurricanes due to the Pliocene warming. Geographically, the studies of the Neogene coastal boulder deposits have been undertaken in different parts of the world, but generally in those locations where rocky shores occur nowadays. The relevance of these deposits to storms and tsunamis, rocky shores and deltas, gravity processes, and volcanism has been discussed; however, some other mechanisms of boulder production, transportation, and accumulation (e.g., linked to seismicity and weathering) have been missed.

The virtuous integration of Geoscience research and educational projects: examples from the Piemonte region

During the MIUR Plan for enhancing scientific degrees (PLS 2015-17), the Italian geological community has been involved in a great effort to bring science and research to the young generations and to help them achieving in-depth knowledge and long lasting success in the STEM sciences.We offered two field laboratories to Upper secondary education students and teachers, developed from the geotours of the PROGEO- Piemonte, promoting the conservation and dissemination of geological heritage through research and outreach activities. They explore the geology of southern and northern Piemonte integrating research, dissemination and geoscience education, and were designed and led by researchers and wildlife guides in the Langhe- Roero-Monferrato World heritage Site, and the Sesia Val Grande Global Geopark. To attract the interest of students and teachers we combined an inquiry-based approach, educational activities of cooperative learning, and the use of multimedia tools.To monitor whether the goals of the PLS were fulfilled, satisfaction questionnaires were administered to both pupils and their teachers. The outcome showed that involving the pupils in field research activities allowed to improve their disciplinary knowledge, their soft skills, and contributed to increase their awareness that the Geosciences are not only interesting, but that they permeate our daily life.

The earthquake and tsunami of 426 BC in Greece: observations by Thucydides and contextual interpretations

The earthquake and subsequent tsunami in the Maliac Gulf in Greece in 426 BC were so im- pressive that several authors, but especially Thucydides, left us with detailed reports of the phenomena, events and damage. We reinterpret these descriptions and use maps of different intensities (EMS- or ESI-Scale) to show the extent of destruction. Thus, we contribute to hazard and risk assessment based on archaeo- and palaeoseismological interpretations, because there is a lack of geoscientific research and unambiguous results in this area to confirm the descriptions.

Reconciling Storegga tsunami sedimentation patterns with modelled wave heights: A discussion from the Shetland Isles field laboratory

AbstractThe Shetland Isles represent an ideal field laboratory for tsunami geoscience research. This is due to the widespread preservation of Holocene tsunami sediments in coastal peat deposits. This study uses published accounts of the Holocene Storegga Slide tsunami to illustrate how two different approaches – mapping of tsunami sediments and numerical modelling – produce radically different run‐up heights. The Storegga Slide is one of the world largest submarine slides and took place ca 8150 cal yr bp on the continental slope west of Norway. The tsunami generated by the landslide deposited locally extensive sheets of marine sand and gravel, as well as redeposited clasts of peat across the contemporary land surface. These sediment accumulations have subsequently been buried by peat growth during the Holocene while exposures of the deposits are locally visible in coastal cliff sections. In several areas, the tsunami sediments can be traced upslope and inland within the peat as tapering sediment wedges up to maximum altitudes of between ca 8·1 m and 11·8 m above present sea level. Since reconstructions of palaeo‐sea level for Shetland for ca 8150 cal yr bp suggest an altitude of 20 m below high tide on the day that the tsunami struck, it has been inferred that the minimum tsunami run‐up was locally between 28·1 m (8·1 + 20 m) and 31·8 m (11·8 + 20 m). However, numerical models of the tsunami for Shetland suggest that the wave height may only have reached a highest altitude in the order of +13 m above sea level on the day the tsunami took place. In this paper a description is given of the sedimentary evidence for tsunami run‐up in the Shetland Isles. This is followed by an evaluation of where the palaeo‐sea level was located when the tsunami occurred. Significant differences are highlighted in tsunami inundation estimates between those based on the observed (geological) data and the theoretically‐modelled calculations. This example from the Shetland Isles may have global significance since it exemplifies how two different approaches to the reconstruction of tsunami inundation at the coast can produce radically different results with modelled wave height at the coast being considerably less than the geological estimates of tsunami run‐up.

BiLSTM-CRF for geological named entity recognition from the geoscience literature

Many detailed geoscience reports lie unused, offering both challenges and opportunities for information extraction. In geoscience research, geological named entity recognition (GNER) is an important task in the field of geoscience information extraction. Regarding numerical geoscience data, research on information extraction remains limited. Most conventional NER approaches are heavily dependent on feature engineering, and such sentence-level-based methods suffer from the tagging inconsistency problem. Based on the above observations, this paper proposes a neural network approach, namely, attention-based bidirectional long short-term memory with a conditional random field layer (Att-BiLSTM-CRF), for name entity recognition to extract information entities describing geoscience information from geoscience reports. This approach leverages global information learned from an attention mechanism to enforce tagging consistency across multiple instances of the same token in a document. Experiments on the constructed dataset show that our method achieves comparable performance to that of other state-of-the-art systems. Additionally, our method achieved an average F1 score of 91.47% in the NER extraction task.

Early history of petroleum exploration offshore Norway and its impact on geoscience teaching and research

Early history of petroleum exploration offshore Norway and its impact on geoscience teaching and research

Virtual Display System of Geological Body Based on Key Algorithms of Three-dimensional Modelling

In order to study the virtual display system of geological body, the key algorithm of three-dimensional modelling is used to analyze it, and the virtual display scheme of geological body is realized. Three-dimensional modelling of geological bodies is a frontier field of current geoscience research, and also a hot issue in computer science. Its research can complement and improve the theoretical basis of virtual reality technology and expand its application fields. Geological body three-dimensional modelling software can meet the needs of geoscientists to study geological problems more effectively from three-dimensional space, and has considerable practical value. In the network environment, users' information needs are diversified and individualized, and special attention is paid to the breadth, novelty and timeliness of information. Faced with massive information resources, the information users need is a drop in the ocean in the huge and disorderly network information space. Users need to spend a lot of time and energy to find valuable information in all kinds of uniform systems. Traditional system information services can no longer help users effectively get rid of information overload and information lost. Therefore, the concept of personalized service system has become a hot spot of people' s attention as soon as it is put forward. In recent years, personalized systems have emerged in endlessly. In the early stage of formulation and implementation of personalized service strategy, the existing personalized service generally lacks the attention to context information such as user' s environment. There are weak links in personalization and intellectualization of service, which damages user experience. Therefore, Shepard algorithm and Kriging algorithm of three-dimensional modelling are used to study the virtual display system of geological bodies. The results show that these two key algorithms play a very important role in the research process of geological virtual display system, and also provide a new idea for further research on the popularization of geological knowledge.

GeoBeam: A distributed computing framework for spatial data

Artificial intelligence and big data technology are important technical means to improve quantitative understanding of natural phenomena in Earth sciences. Large-scale spatial data provides a basic geospatial background for geoscience research. An effective and efficient distributed computing frame for spatial data is an indispensable infrastructure. It is still a challenge for disk-based distributed computing framework to analyze and process large-scale data efficiently. Such a challenge has driven the rapid development of various memory-based distributed computing platforms such as Spark, Flink, Apex, and more. Now, it is urgent to develop an efficient platform-independent distributed computing framework with a unique focus on large-scale spatial data. This paper provides a memory-based distributed computing framework named GeoBeam. It abstracts all the operations of spatial data into spatial pipeline, collection and transforms. Finally, they are encapsulated as feature dataset and feature store interfaces in GIS to shield the details of the underlying distributed operations. Experimental results show that GeoBeam can support efficient range query and processing of large-scale spatial data on Spark cluster and Flink cluster. GeoBeam provides an effective cross-platform distributed computing solution for fast processing of large-scale spatial data.

Soil Functions: Connecting Earth's Critical Zone

Soil is the central interface of Earth's critical zone—the planetary surface layer extending from unaltered bedrock to the vegetation canopy—and is under intense pressure from human demand for biomass, water, and food resources. Soil functions are flows and transformations of mass, energy, and genetic information that connect soil to the wider critical zone, transmitting the impacts of human activity at the land surface and providing a control point for beneficial human intervention. Soil functions are manifest during bedrock weathering and, in fully developed soil profiles, correlate with the porosity architecture of soil structure and arise from the development of soil aggregates as fundamental ecological units. Advances in knowledge on the mechanistic processes of soil functions, their connection throughout the critical zone, and their quantitative representation in mathematical and computational models define research frontiers that address the major global challenges of critical zone resource provisioning for human benefit. ▪ Connecting the mechanisms of soil functions with critical zone processes defines integrating science to tackle challenges of climate change and food and water supply. ▪ Soil functions, which develop through formation of soil aggregates as fundamental eco-logical units, are manifest at the earliest stages of critical zone evolution. ▪ Global degradation of soil functions during the Anthropocene is reversible through positive human intervention in soil as a central control point in Earth's critical zone. ▪ Measurement and mathematical translation of soil functions and critical zone processes offer new computational approaches for basic and applied geosciences research.

Geo‐Data Science: Leveraging Geoscience Research with Geoinformatics, Semantics and Open Data

Geo‐Data Science: Leveraging Geoscience Research with Geoinformatics, Semantics and Open Data

Project and Community Management in Polar Sciences – Challenges and Opportunities

Abstract. Because geoscientific research often occurs via community-instigated bursts of activity with multi-investigator collaborations variously labelled as e.g., years (The International Polar Year IPY), experiments (World Ocean Circulation Experiment WOCE), programs (International Ocean Discovery Program), missions (CRYOSAT spacecraft), or decades (The International Decade of Ocean Exploration IDOE), successful attainment of research goals generally requires skilful scientific project management. In addition to the usual challenges of matching scientific ambitions to limited resources, on-going coordination and specifically project management, planning and implementation of polar science projects often involve many uncertainties caused by, for example, unpredictable weather or ocean and sea ice conditions, large-scale logistical juggling; and often these collaborations are spatially distributed and take place virtually. Large amounts of funding are needed to procure the considerable infrastructure and technical equipment required for polar expeditions; permissions to enter certain regions must be requested; and potential risks for expedition members as well as technical issues in extreme environments need to be considered. All these aspects are challenging for polar science projects, which therefore need a well thought-through program including a realistic alternative “plan B” and possibly also a “plan C” and “plan D”. The four most challenging overarching themes in polar science project management have been identified: international cooperation, interdisciplinarity, infrastructure, and community management. In this paper, we address ongoing challenges and opportunities in polar science project management based on a survey among 199 project and community managers and an additional of 85 project team members active in the field of polar sciences. Case studies and survey results are discussed with the conclusive goal to provide recommendations on how to fully reach the potential of polar sciences project and community management.

Exploring the long-term academic and career impacts of undergraduate research in geoscience: A case study

Undergraduate research experiences (UREs) have been shown to facilitate students’ pursuit of graduate studies and careers in science, technology, engineering, and mathematics (STEM) fields, including geoscience. Less is known about why or how UREs have a lasting impact on participants, particularly through graduate school and into careers. Furthermore, few studies have captured the views and experiences of former URE participants no longer in STEM. The present study used purposive sampling and semistructured interviews to explore the long-term academic and career impacts of a summer-long geoscience URE (4 to 7 years post-URE; M = 5.4) on 10 former participants: 4 in STEM graduate school, 4 in STEM careers, and 2 in non-STEM careers. During interviews, participants described key long-term URE impacts within three interrelated domains: research/science, graduate school, and careers. These came about through a combination of significant relationships (e.g., mentors) and heightened self-awareness (e.g., clarity of career aspirations), which participants developed during the URE. Often, participants spoke of seemingly proximal URE outcomes that retained or gained significance over time. For example, the URE offered immersive experiences (e.g., in laboratory science) and opportunities for professional development (e.g., programing) that gave participants insight and skills related to their future endeavors. Drawing on these emergent themes, we discuss the importance of examining long-term URE impacts towards a deeper understanding of their benefits and toward the design of more effective URE programs.

Fractal characteristics based on different statistical objects of process-based digital rock models

Fractal characteristics of porous media have been a focus of research in geosciences for several decades and measuring fractal dimensions has become a common method to describe the structural properties of porous media. In this paper, the fractal dimensions of solid phase, pore phase and interface between them are studied by box counting method based on digital rocks. The process-based modeling technique is utilized to construct models with different pore structure firstly, which includes four kinds: grain-size contrast, grain-size variety, compaction and cementation. Then the fractal dimensions of solid, pore and interface of these models are calculated and analyzed using box counting method through different statistical objects. Finally, the fractal dimensions of real digital rocks are calculated, and the relationship between fractal dimensions and rock properties such as pore structure, porosity and permeability is qualitatively analyzed. The research results indicate that only the interface fractal dimension can better distinguish and characterize the pore structure of process-based digital rock models with slight variation in porosity. On the other hand, if porosity of these models varies significantly, both pore fractal dimension and interface fractal dimension are available to distinguish and represent pore structure well, and pore fractal dimension is more sensitive and active to the change of pore structure and porosity. When using fractal dimensions to represent and analyze pore structure of real rocks, the fractal dimensions of pore and interface should be considered comprehensively. Furthermore, the interface fractal dimension is better than the pore fractal dimension in characterizing the pore structure of some sandstone digital rocks.

New Evidence of the Bangestan Geoheritage Resource in Iran: Beyond Hydrocarbon Reserves

Iran boasts internationally important deposits of hydrocarbons. The hydrocarbons can be regarded not only as an exceptional energy resource, but also a geological heritage (geoheritage) resource. A new investigation of the Bangestan carbonate rocks from the Cretaceous age in the Fars Province has permitted to find several unique features and to assign these to six geoheritage types, namely sedimentary, palaeontological, stratigraphical, palaeogeographical, structural, and economic. The most important from these is the economic type that is ranked nationally. The Bangestan geoheritage is valuable for geoscience research, geoeducation, and geotourism, and this geoheritage is a subject of geoconservation. As these activities can bring some socio-economic benefits, this geoheritage has to be considered a true natural resource. Field studies have permitted to emphasize its appropriate manifestation in the Nowdan anticline (an area in the Zagros Mountains near the cities of Shiraz and Kazeroon), which is suggested as a geosite. Hydrocarbon-related industrial tourism and geotourism activities can be coupled for their mutual benefit. The Nowdan anticline geosite should be used for the purposes of tourism, but it requires some simple infrastructure building and involvement in excursion programs coordinated by a local museum or visitor centre.

GemPy 1.0: open-source stochastic geological modeling and inversion

Abstract. The representation of subsurface structures is an essential aspect of a wide variety of geoscientific investigations and applications, ranging from geofluid reservoir studies, over raw material investigations, to geosequestration, as well as many branches of geoscientific research and applications in geological surveys. A wide range of methods exist to generate geological models. However, the powerful methods are behind a paywall in expensive commercial packages. We present here a full open-source geomodeling method, based on an implicit potential-field interpolation approach. The interpolation algorithm is comparable to implementations in commercial packages and capable of constructing complex full 3-D geological models, including fault networks, fault–surface interactions, unconformities and dome structures. This algorithm is implemented in the programming language Python, making use of a highly efficient underlying library for efficient code generation (Theano) that enables a direct execution on GPUs. The functionality can be separated into the core aspects required to generate 3-D geological models and additional assets for advanced scientific investigations. These assets provide the full power behind our approach, as they enable the link to machine-learning and Bayesian inference frameworks and thus a path to stochastic geological modeling and inversions. In addition, we provide methods to analyze model topology and to compute gravity fields on the basis of the geological models and assigned density values. In summary, we provide a basis for open scientific research using geological models, with the aim to foster reproducible research in the field of geomodeling.

Anton Linder Hales 1911–2006

Anton Linder Hales died in Canberra on 11 December 2006. He was a distinguished geophysicist of international renown who made major contributions to understanding the structure and evolution of the deep Earth through the combination of theoretical developments, field experimentation and laboratory measurements, including in whole-mantle convection, palaeomagnetism, geochronology and seismology. He was also a creative and highly successful builder of research institutions on three continents, in South Africa, the USA and Australia. The last of these was as Foundation Director of the Research School of Earth Sciences at the Australian National University, leaving behind one of the leading geoscience research institutions in the world. His career spanned a period in which earth science was undergoing rapid evolution—from a ‘fixist’ view of the planet to the ‘highly dynamic’ view that we have today, an evolution to which he made important contributions both through his own research and his scientific leadership at institutional and international level.

COMPARATIVE ANALYSES OF COMBUSTION EFFICIENCIES OF COALS FROM NIGERIA FOR POWER GENERATION

Three coal samples from Onyeama (Enugu State), Owukpa (Benue State) and Odagbo (Kogi State) in Nigeria were collected and tested. These were characterized to determine the proximate and the ultimate analyses, calorific value and the thermogravimetric analysis, and their combustion efficiencies for power generation comparatively analyzed. The proximate analysis and the calorific value tests were done at the Energy Research Center, University of Nigeria – Nsukka, while the ultimate analysis test was conducted at the National Geosciences Research Laboratory, Kaduna. Also, the thermogravimetric analysis was carried out at the Energy Research Center, Usman Danfodio University, Sokoto. From the test results, the moisture contents ranged from 10.60 to 16.80%. The Owukpa coal sample had the highest moisture content of 16.80%, followed by Odagbo with 15.95% and Onyeama bearing 10.60%. The volatile matter contents of the samples indicated that Owukpa had the highest value of 19.95%, followed by Onyeama with 18.65% and Odagbo having the least value of 18.58% respectively. Similarly, the Owukpa coal sample had the highest fixed carbon of 55.22% followed by Onyeama with 53.36% and Odagbo with the lowest value of 50.38%, while the ash contents showed Onyeama to possess the highest value of 17.39%, and closely followed by Odagbo with 15.06% and Owukpa having the lowest content of 8.03%. Moreso, Onyeama coal sample with the highest fuel ratio of 2.86 would give the best ease of ignition and fuel burnout followed by Owukpa (2.77), and Odagbo (2.71). The percentages of the elemental carbon of Onyeama, Owukpa and Odagbo coal samples were 52.2170, 53.8178 and 50.8754% respectively, while the hydrogen contents indicated Onyeama (4.7236%), Owukpa (4.0141%) and Odagbo (3.8163%). The nitrogen, sulphur and oxygen contents obtained revealed Onyeama (1.3756, 0.10 and 13.6938%), Owukpa (1.4350, 0.10 and 15.9031%) and Odagbo (1.4260, 0.92 and 12.8423%) respectively. Consequently, the Onyeama coal sample had the highest heating value of 32.916MJ/kg, followed by Odagbo (32.037MJ/kg) and Owukpa (30.062MJ/kg). Based on the comparative analyses, the Onyeama coal indicated the overall best fuel sample followed by Owukpa and then Odagbo in that order in-view of their fuel ratio, combustion efficiencies, quality of the fuel, ease of ignition and fuel burnout.