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Preparing a term paper requires students to acquire thorough knowledge of a topic through study of the literature and to prepare a written summary in the student's own words. Although most reference materials for term papers should be from published literature, the Internet provides abundant sources from which to select a topic and gather information. Due to the irregular distribution of information on the Internet, locating specific information can be very challenging, especially for novice users. Students should be cautious when using Internet sources for a term paper, as the Internet does not have the high content standards typical of professional journals. This paper is intended as a short guide to be presented to students as part of a term-paper assignment. A style guide for the citation of Internet sources is also presented.

This paper analyses the mechanical and mathematical models in Yanbin Wang et al.‘s six papers on mechanical analysis of marine riser: “Wang, Yanbin, Gao, Deli, Fang, Jun 2014. Static analysis of deep-water marine riser subjected to both axial and lateral forces in its installation. J. Nat. Gas Sci. Eng. 19, 84–90”, “Wang, Yanbin, Gao, Deli, Fang, Jun 2014. Axial dynamic analysis of marine riser in installation. J. Nat. Gas Sci. Eng. 21, 112–117”, “Wang, Yanbin, Gao, Deli, Fang, Jun 2015. Coupled dynamic analysis of deepwater drilling riser under combined forcing and parametric excitation. J. Nat. Gas Sci. Eng. 27, 1739–1747”, “Wang, Yanbin, Gao, Deli, Fang, Jun 2015. Study on lateral vibration analysis of marine riser in installation-via variational approach. J. Nat. Gas Sci. Eng. 22, 523–529”, “Wang, Yanbin, Gao, Deli, Fang, Jun 2015. Mechanical behavior analysis for the determination of riser installation window in offshore drilling. J. Nat. Gas Sci. Eng. 24, 317–323”, and “Wang, Yanbin, Gao, Deli, Fang, Jun 2015. Finite element analysis of deepwater conductor bearing capacity to analyze the subsea wellhead stability with consideration of contact interface models between pile and soil. J. Pet. Sci. Eng. 126, 48–54”; and finds that the mechanical and mathematical models described in these papers are clearly incorrect. Therefore, new mechanical and mathematical models have been suggested in this study. Keywords: Marine riser, Mechanical analysis, Mechanical model, Mathematical model

Filter paper technique (FPT) is known to measure both matric and total suctions in a wide measurement range. However, it has many individual errors due to the uncertainty of calibration curve and sensitivity of the measurements to the temperature and relative humidity variations. Besides, the ASTM procedure for FPT does not specify any sample preparation and repetition for experiments. In this regard, this study covers the reliability of suction measurements using the FPT and its application on zeolite–bentonite mixtures (ZBMs), which were proposed for use of liner material in the literature. A calibration curve for Whatman No. 42 filter paper was constructed and compared to the other calibration curves given in the literature. Due to large scatter of calibration curves, total suction measurement is found to be inconvenient for suction values under 1000 kPa. An improvement in sample preparation and necessary minimum numbers of tests are also suggested. When preparing the test specimen, the compacted sample is recommended not to be cut but to be compacted separately as upper and lower parts where the contact filter paper to be placed in between in order to obtain good contact area to measure the matric suction accurately. The necessary minimum numbers of tests for ± 10% accuracy band in a confidence level of 95% for ASTM procedure on ZBMs are suggested. Repetitions were found to vary depending on the suction type and bentonite content. Repetitions of six and eight times are recommended for 10% ZBMs for matric and total suction measurements, respectively. Similarly, for 20% ZBMs the repetitions of six and ten times are found for matric and total suction measurements, respectively. In addition, the influence of index properties and compaction states on suction was also investigated. Matric suction values decrease from dry of optimum water content to the wet of optimum water content and approach to zero for higher water contents. The suction values are found to increase with decreasing water contents where the dry density and the void ratio were constant. On the other hand, for a given water content, matric suction values are found to be increasing with increasing dry densities, while the void ratio was decreasing being more evident at relatively higher saturation degrees. © 2017, Springer-Verlag GmbH Germany.

Roček, Zbyněk (2016): Bibliography Of Original Scientific Papers And Books By Zdeněk V. Špinar. Fossil Imprint 72 (1-2): 9-14, DOI: 10.14446/FI.2016.9, URL: http://dx.doi.org/10.14446/fi.2016.9

The paper by Sell et al. (2014) reports new, high quality and high precision data that constrain the Lower Toarcian time scale, and provides further dates from the K-LIP,1 emplaced during the same time interval. The Early Toarcian records an episode of mass extinction of marine fauna correlated with a global negative CIE. The extensive magmatism of the K-LIP has been proposed as the leading explanation for the environmental changes (Svensen et al., 2007, 2012; McElwain et al., 2005). In past studies we and coauthors have investigated this potential association by dating sills of the K-LIP event across South Africa (Svensen et al., 2012) and verifying the stratigraphic correlation using a fossiliferous bentonite-bearing shale section in western Argentina (Mazzini et al., 2010). We have also conducted a number of detailed investigations of the mode of emplacement of the Karoo sills and their effects on the intruded sedimentary rocks, concluding that the heat from the intrusions contributed to devolatilization

Current desktop technology is largely mouse-driven, but many analysts predict that in less than five years we will have a professional workforce that have only experienced learning in a touchscreen environment. Midland Valley have developed a digital mapping tool for smartphones called FieldMove Clino, which has been downloaded more than 20 000 times over the past year. The free version offers an effective way of introducing students to digital field mapping. However, many geoscience departments and teachers of field mapping have yet to make the switch from traditional paper-based methods to digital technology. This article aims to answer some of the frequently asked questions about digital field mapping and outlines some of the advantages for improving field skills and geological thinking in students.

The paper published by Sial et al. (2016) contains geochemical information which does not fit into the scheme of the existing planktonic foraminiferal succession across the K/Pg boundary in the Um Sohryngkew River section, Meghalaya India, worked out by either Mukhopadhyay (2008) or Pandey (1981, 1990). The K/Pg boundary reported by Sial et al. (2016) is not compatible with any of these two. In this perspective some of the controversies are highlighted.

We welcome the discussion of our paper on the geological map of the central sector of the Montagna dei Fiori by Santantonio and co-workers, because this will contribute to improving the understanding of the complex geological setting of the area and, eventually, helping to disentangle the pre-orogenic and syn-orogenic evolutionary history that is recorded in the tectono-sedimentary pattern exposed in the Montagna dei Fiori anticline.

Alkenylsuccinic Anhydride (ASA) is commonly applied as oil-in-water emulsions in papermaking industry. Herein, a particle stabilized ASA emulsion was developed for avoiding the adverse effect of surfactant, further improving the sizing performance and reducing the hydrolysis of ASA Pickering emulsions, where Laponite nanoparticles were employed as a stabilizer of the ASA Pickering emulsions after being modified with carbon nitride quantum dots. It was found that the hydrophilic Laponite particles became partially hydrophobic after being modified with CNQDs in dosage of 20–40 wt%, and thus promoted the formation of emulsions with fine and uniform droplets that resisted creaming/coalescence formation. The adsorption of the Laponite/CNQDs particles on the ASA droplet surface improved the emulsion stability, which was verified by fluorescent confocal laser scanning microscopy. Meanwhile, by using Laponite/CNQDs nanoparticles, the storage stability of ASA Pickering emulsion and its sizing performance on paper was also improved.

In the paper entitled “Two independent real-time precursors of the 7.8 M earthquake in Ecuador based on radioactive and geodetic processes – Powerful tools for an early warning system”, Toulkeridis et al. (2019) claim that they found radiation and GPS signal anomalies before the April 16th 2016 Pedernales earthquake (Ecuador) and that their findings can be used to forecast earthquakes in the medium and short term in active continental margins. Using an extended data set that overlaps Toulkeridis et al. (2019) study period, we find: (1) the success rate of predicting earthquakes using radiation anomalies is 2.5 %; (2) radiation anomalies, including the one recorded during the hours before the M 7.8 earthquake, temporally correlate with local rainfall; (3) Toulkeridis et al. (2019) GPS results are physically unrealistic and inconsistent with previously published GPS and InSAR analysis; (4) there is no anomaly in the GPS time series before the earthquake. Therefore, Toulkeridis et al. (2019) results are not reliable evidence of precursors to the M 7.8 earthquake in 2016 in Ecuador, and their proposed method cannot be used to forecast earthquakes.

Marine seismic reflection data have been collected for decades and since the mid-to late- 1980s much of this data is positioned relatively accurately. This older data provides a valuable archive, however, it is mainly stored on paper records that do not allow easy integration with other datasets. A method for converting these records to digital SEGY format has been reported previously, although the accuracy and reliability has not been documented. Using 3.5 kHz pinger, bathymetric and side scan sonar data we test the accuracy and data resolution of converted paper seismic records on the surface and shallow-subsurface of the Barra Fan, NE Atlantic Ocean. Frequencies of navigational updates and printed fix marks are vital in determining positional accuracy as interpolation between fixes, which may be 30 minutes apart, is a significant source of potential error. Vertical data resolution of the converted records is primarily governed by the dimensions of the printed record, with order of magnitude differences noted between the scanned BGS and NOC pinger records. Positional accuracy of pinger data is observed to be within the resolution of the bathymetric grid. BGS 1985 pinger data is located within 40 m of bathymetric constrained locations at 635 m below mean sea level and NOC 1998 pinger data within 25 m of bathymetric locations at 1180 m below mean sea level. This paper-to-digital conversion is not a replacement for modern data acquisition, but it does provide a valuable complement to such data. Where appropriate archival paper data is available for conversion it could be used to assist efficiency of forthcoming surveys and may be used to provide time series evidence of seabed processes.

Joint Paper with Collegues

This short note provides comments and a response to the paper published in Earth Systems and Environment by Albert Parker and Clifford D. Ollier (Volume 1, December 2017) entitled “Is the Sea Level Stable at Aden, Yemen?”

This short film, “From a Sheet of Paper to the Sky”, grew out of research that I conducted for an essay of the same title, written for the catalogue accompanying the Paul Nash exhibition at Tate Britain (October 2016 to March 2017). In that essay, I argued against the traditional art historical tendency to review an artist’s work in different media separately, and instead proposed that a consideration of Paul Nash’s painting alongside his three-dimensional and textile designs, his printmaking, and photography, resulted in a fuller understanding of both the conceptual underpinnings and the recurring visual motifs in Nash’s work.

Because of a combination of new observational tools and a flurry of large megathrust earthquakes, tremendous progress has been made in recent years towards understanding the process of great subduction earthquakes at Cascadia and other subduction zones around the world. This review article attempts to clarify some of widely used geodynamic concepts and identify the most important scientific questions for future research related to megathrust behaviour. It is important to specify how the megathrust seismogenic zone has been defined when comparing data and models. Observations and concepts currently used to define the seismogenic zone include: (A) the stability transition in rate-and-state dependent friction; (B) the slip zone of large interplate earthquakes; (C) the distribution of small-medium earthquakes; and (D) the geodetically-determined zone of fault locking. Land-based geodetic measurements indicate that the Cascadia megathrust is locked to some extent, but the degree of locking is not well constrained. The near absence of detectable interplate seismicity, with the exception of a segment near 44.5°N and near the Mendocino Triple Junction, is presently interpreted to indicate full locking along most of Cascadia. Resolving the locking state requires seafloor geodetic measurements. The slip behaviour of the shallowest segment of the megathrust and its tsunamigenic potential are complex and variable. Structural studies combined with modeling have the potential to improve our understanding of the signature left in the structure by the slip history. For several reasons, but mostly because of interseismic viscoelastic stress relaxation, the downdip limit of megathrust locking cannot be reliably constrained by geodetic data. Independent information is needed on the composition and thermal state of fault zone materials. The spatial relationship between the seismogenic zone and the zone of Episodic Tremor and Slip (ETS) remains controversial. Observations from the Nankai subduction zone and the San Andreas Fault suggest that ETS does not mark a simple spatial transition from seismic to aseismic behaviour and that multiple transitions may be present because of petrological and rheological changes with depth. Coseismic rupture in the AD 1700 Cascadia earthquake has been shown to vary along strike, and it is important to investigate whether the position of boundaries between high slip and low slip are stationary with time (and therefore probably geologically controlled) and are reflected in current interseismic locking of the megathrust.

This note deals with the mechanical behaviour of lateral filter paper drains, used in triaxial testing in the laboratory. It has been found that the maximum influence of the filter paper drain on the measured deviator stress coincides with the development of folds during axial straining. Subsequent reuse of the same filter paper drain caused a significant drop of about 70% in the maximum value of the influence.

Many types of hydrothermal ore deposits form at overpressured conditions during high fluid flux through fault zones in the continental seismogenic regime. These include many orogenic gold deposits, some types of Fe oxide Cu-Au systems, and a variety of intrusion-related deposits, including some high-sulfidation epithermal systems. The internal structures of these deposits indicate formation while faults were active, in a regime involving episodic slip. Partial to complete sealing of fault zones by precipitation of hydrothermal minerals occurs between slip episodes. Such ore deposits occur typically within low displacement faults, or networks of such faults. Lodes seldom occupy areas much greater than 1 km 2 of fault surfaces, and net slip accumulated during ore formation is typically less than 150 m. Fluid injection experiments in low-permeability rocks, and seismicity styles in hydrothermally active settings, provide new insights about the dynamics of ore formation in high fluid-flux faults. In particular, they indicate that swarm seismicity is the characteristic response to injection of large volumes of overpressured fluids into intrinsically low-permeability rock. Injection-driven swarm seismicity and related permeability enhancement involves repeated sequences of thousands of ruptures, mostly with moment magnitude M w in the range −2 w 2 ; maximum cumulative slip is usually less than a few centimeters. Diffusion-like migration of a seismicity front away from the injection source at rates up to hundreds of meters per day is a key characteristic of injection-driven seismicity, and correlates with migration of a fluid pressure front along activated faults. By analogy with injection experiments and natural injection-driven swarm seismicity, the formation of fault-related ore deposits in overpressured, high fluid-flux regimes is interpreted to involve swarm seismicity, rather than mainshock-aftershock sequences. Recurrence intervals of swarms in contemporary injection-driven swarm sequences indicate that the total slip associated with formation of fault-hosted lodes can accumulate in periods as short as 104 to 105 years, during thousands of swarm episodes, and commonly involve >10 6 ruptures with −2 w 4 to 10 5 m 3 of fluid at injection rates of at least several tens of L.s −1 . Up to tens of kg Au are deposited per swarm. Cascades of thousands of microseismic ruptures and associated permeability enhancement, coseismic dilatancy, and fluid pressure changes during individual injection-driven swarm sequences create very dynamic hydrologic and reaction regimes. Ore formation involving transitory bursts of rapid flow, abrupt fluctuations in flow rates and fluid pressures, and possibly also fluid temperatures, is likely to promote severe chemical disequilibrium. This has implications for controls on ore deposition and grade distribution in many fault-related ore systems.

Igneous intrusions, notably carbonatitic–alkalic intrusions, peralkaline intrusions, and pegmatites, represent significant sources of rare-earth metals. Geophysical exploration for and of such intrusions has met with considerable success. Examples of the application of the gravity, magnetic, and radiometric methods in the search for rare metals are presented and described. Ground gravity surveys defining small positive gravity anomalies helped outline the shape and depth of the Nechalacho (formerly Lake) deposit within the Blatchford Lake alkaline complex, Northwest Territories, and of spodumene-rich mineralization associated with the Tanco deposit, Manitoba, within the hosting Tanco pegmatite. Based on density considerations, the bastnaesite-bearing main ore body within the Mountain Pass carbonatite, California, should produce a gravity high similar in amplitude to those associated with the Nechalacho and Tanco deposits. Gravity also has utility in modelling hosting carbonatite intrusions, such as the Mount Weld intrusion, Western Australia, and Elk Creek intrusion, Nebraska. The magnetic method is probably the most successful geophysical technique for locating carbonatitic–alkalic host intrusions, which are typically characterized by intense positive, circular to sub-circular, crescentic, or annular anomalies. Intrusions found by this technique include the Mount Weld carbonatite and the Misery Lake alkali complex, Quebec. Two potential carbonatitic–alkalic intrusions are proposed in the Grenville Province of Eastern Quebec, where application of an automatic technique to locate circular magnetic anomalies identified several examples. Two in particular displayed strong similarities in magnetic pattern to anomalies accompanying known carbonatitic or alkalic intrusions hosting rare-metal mineralization and are proposed to have a similar origin. Discovery of carbonatitic–alkalic hosts of rare metals has also been achieved by the radiometric method. The Thor Lake group of rare-earth metal deposits, which includes the Nechalacho deposit, were found by follow-up investigations of strong equivalent thorium and uranium peaks defined by an airborne survey. Prominent linear radiometric anomalies associated with glacial till in the Canadian Shield have provided vectors based on ice flow directions to source intrusions. The Allan Lake carbonatite in the Grenville Province of Ontario is one such intrusion found by this method. Although not discovered by its radiometric characteristics, the Strange Lake alkali intrusion on the Quebec–Labrador border is associated with prominent linear thorium and uranium anomalies extending at least 50 km down ice from the intrusion. Radiometric exploration of rare metals hosted by pegmatites is evaluated through examination of radiometric signatures of peraluminous pegmatitic granites in the area of the Tanco pegmatite.