Dynamic Earth Research Articles

The Swedish Deep Drilling Program: the quest for the Earth's inner secrets

The Swedish Deep Drilling Program (SDDP) has been initiated to study fundamental problems of the dynamic Earth system, its natural history and evolution. Many key scientific questions can be addressed through in situ investigations only, requiring deep continental drilling. Some are unique to Scandinavia, most are of international interest and significance. At present, five core projects (Fig. 1) with international teams are integrating scientific problems with societal and industrial applications. If SDDP succeeds to attract the funding required, Sweden will have a number of world‐class boreholes at key locations by 2020.Locations of SDDP drilling project proposals. PFDP—Postglacial Fault Drilling Project; PaMVAS—Palaeoproterozoic mineralized volcanic arc systems: the Skellefte District; COSC—Collisional Orogeny in the Scandinavian Caledonides; DRL—The Dellen Impact Crater, a geoscientific deep rock laboratory; SELHO—Svecofennian accretion, an example of the early structural evolution in a large hot orogen; CISP—Concentric Impact Structures in the Palaeozoic: the Lockne and Siljan craters. Background and inset image from Blue Marble Next Generation data set (NASA Earth Observatory, http://earthobservatory.nasa.gov/Features/BlueMarble/).image

Geodetic Observations of Glacial Isostatic Adjustment: Understanding Glacial Isostatic Adjustment: A Joint DynaQlim/GGOS Workshop; Espoo, Finland, 23–26 June 2009

The phenomenon of glacial isostatic adjustment (GIA), with its unique temporal and spatial signatures, provides one of the great opportunities in the geosciences for obtaining information about dynamic Earth processes. GIA contains information about recent climate forcing, being dependent on the geologically recent loading and unloading of ice sheets. It presents a unique opportunity to study the dynamics and rheology of the lithosphere and mantle; is responsible for substantial sea level variations; and is of fundamental importance to geodesy because site positions, reference frames, Earth rotation, and gravity are all influenced by GIA.The Global Geodetic Observing System (GGOS) of the International Association of Geodesy and the International Lithosphere Program's Regional Co‐ordination Committee Upper Mantle Dynamics and Quaternary Climate in Cratonic Areas (DynaQlim) jointly organized a workshop that attracted 36 international scientists to Finland. The objectives of this workshop were to (1) review the current state of the science in modeling GIA, (2) review the use of geodetic measurements to constrain and test GIA models, (3) identify obstacles to improving GIA models, and (4) identify improvements to the global geodetic observing system that are required to better understand GIA.

Charles Darwin’s Origin of Species, directional selection, and the evolutionary sciences today

The book On the Origin of Species, published in November 1859, is an "abstract" without references, compiled by Charles Darwin from a much longer manuscript entitled "Natural Selection." Here, I summarize the five theories that can be extracted from Darwin's monograph, explain the true meaning of the phrase "struggle for life" (i.e., competition and cooperation), and outline Darwin's original concept of natural selection in populations of animals and plants. Since neither Darwin nor Alfred R. Wallace distinguished between stabilizing and directional natural selection, the popular argument that "selection only eliminates but is not creative" is still alive today. However, I document that August Weismann (Die Bedeutung der sexuellen Fortpflanzung für die Selektions-Theorie. Gustav Fischer-Verlag, Jena, 1886) and Ivan Schmalhausen (Factors of evolution. The theory of stabilizing selection. The Blackiston Company, Philadelphia, 1949) provided precise definitions for directional (dynamic) selection in nature and illustrate this "Weismann-Schmalhausen principle" with respect to the evolutionary development of novel phenotypes. Then, the modern (synthetic) theory of biological evolution that is based on the work of Theodosius Dobzhansky (Genetics and the origin of species. Columbia University Press, New York, 1937) and others, and the expanded version of this system of theories, are outlined. Finally, I document that symbiogenesis (i.e., primary endosymbiosis, a process that gave rise to the first eukaryotic cells), ongoing directional natural selection, and the dynamic Earth (plate tectonics, i.e., geological events that both created and destroyed terrestrial and aquatic habitats) were the key processes responsible for the documented macroevolutionary patterns in all five kingdoms of life. Since the evolutionary development of the earliest archaic bacteria more than 3,500 mya, the biosphere of our dynamic planet has been dominated by prokaryotic microbes. Eubacteria, Archaea, and Cyanobacteria are, together with eukaryotic microorganisms (marine phytoplankton, etc.), the hidden "winners" in the Darwinian struggle for existence in nature.

Empirical analysis of the planform curvature‐migration relation of meandering rivers

Meandering rivers are among the most dynamic Earth surface systems, exhibiting progressive change in channel location as they migrate across their floodplains over time. Theoretical models of meandering have defined the influence of planform curvature on meandering in the form of a spatial convolution function that expresses migration at any point along the channel as a weighted aggregate of local, upstream, and, most recently, downstream curvature. This study evaluates empirically the spatial planform curvature‐migration relation of meandering rivers using data obtained from natural meandering rivers with varying degrees of planform complexity and compares the empirical results with the assumed relationships embodied in the theoretical meander migration models. The study is based on a framework that views a meandering river as a dynamical input‐output system where the migration process is characterized by a spatial filter through which planform curvature produces migration. Discrete signal processing is used to derive the spatial planform curvature‐migration relation for each study reach and to analyze the characteristics of this relation via transfer function models. The results demonstrate that the spatial structure of the planform curvature effect on migration rates depends on the complexity of the planform geometry. A first‐order difference equation, in which the planform curvature effect is characterized as an exponential decay, can satisfactorily describe the migration process of a planform containing simple bends, but a high‐order difference equation, which includes oscillatory terms superimposed on exponential decay, is necessary to capture the development of complex meander forms. The findings support recent theoretical studies that suggest that high‐order terms are required in spatial convolution models to generate complex bend geometries.

A Novel Approach to Teaching and Understanding Transformations of Matter in Dynamic Earth Systems

The need to engage K-12 and post-secondary students in considering the Earth as a dynamic system requires explicit discussion of system characteristics. Fundamentally, dynamic systems involve the movement and change of matter, often through processes that are difficult to see and comprehend. We introduce a novel instructional method, termed Cause-MaP, designed to enhance non-science major undergraduates' understanding of complex Earth systems. Students are provided with a mechanism for explicitly following matter as it moves through the environment, and are encouraged to describe this movement both verbally, in response to a structured set of questions, and pictorially, in boxand-arrow diagrams. This approach raises awareness of the underlying causes for the dynamic nature of systems, and encourages reasoning, thoroughness, and transferability of skills. Preliminary data suggest that this method is effective with post-secondary students and we encourage adaptation of Cause-MaP to other courses at both the post-secondary and K-12 levels. A follow-up, more rigorous investigation of the impact of this approach on student learning will clarify the effectiveness of this instructional method.

Environmental justice: lessons on definition and delivery from Scotland

This paper considers the concept of environmental justice in Scotland. It reviews the research and developments in law and policy in this area, starting with the Dynamic Earth speech in Edinburgh in 2002. It analyses the findings by grouping causes and solutions to environmental justice and identifies a particularly wide definition of the concept in Scotland. It concludes that the inclusion of social justice is a defining feature of environmental justice in Scotland; however, measures to mitigate environmental injustice are being implemented in an incremental way, with the most significant achievements being through the implementation of international obligations.

Separation of atmosphere‐ocean‐vegetation feedbacks and synergies for mid‐Holocene climate

We determine both the impact of atmosphere‐ocean and atmosphere‐vegetation feedback, and their synergy on northern latitude climate in response to the orbitally‐induced changes in mid‐Holocene insolation. For this purpose, we present results of eight simulations using the general circulation model ECHAM5‐MPIOM including the land surface scheme JSBACH with a dynamic vegetation module. The experimental set‐up allows us to apply a factor‐separation technique to isolate the contribution of dynamic Earth system components (atmosphere, atmosphere‐ocean, atmosphere‐vegetation, atmosphere‐ocean‐vegetation) to the total climate change signal. Moreover, in order to keep the definition of seasons consistent with insolation forcing, we define the seasons on an astronomical basis. Our results reveal that north of 40°N atmosphere‐vegetation feedback (maximum in spring of 0.08°C) and synergistic effects (maximum in winter of 0.25°C) are weaker than in previous studies. The most important modification of the orbital forcing is related to the atmosphere‐ocean component (maximum in autumn of 0.78°C).

Symbiogenesis, natural selection, and the dynamic Earth

One century ago, Constantin S. Mereschkowsky introduced the symbiogenesis theory for the origin of chloroplasts from ancient cyanobacteria which was later supplemented by Ivan E. Wallin's proposal that mitochondria evolved from once free-living bacteria. Today, this Mereschkowsky-Wallin principle of symbiogenesis, which is also known as the serial primary endosymbiosis theory, explains the evolutionary origin of eukaryotic cells and hence the emergence of all eukaryotes (protists, fungi, animals and plants). In 1858, the concept of natural selection was described independently by Charles Darwin and Alfred R. Wallace. In the same year, Antonio Snider-Pellegrini proposed the idea of shifting continents, which was later expanded by Alfred Wegener, who published his theory of continental drift eight decades ago. Today, directional selection is accepted as the major cause of adaptive evolution within natural populations of micro- and macro-organisms and the theory of the dynamic Earth (plate tectonics) is well supported. In this article, I combine the processes and principles of symbiogenesis, natural selection and the dynamic Earth and propose an integrative 'synade-model' of macroevolution which takes into account organisms from all five Kingdoms of life.

CO2 geological storage field development–Application of baseline, monitoring and verification technology

The creation of a robust Baseline, Monitoring, and Verification (BMV) plan is key to assuring containment integrity in CO2 geological storage projects. A BMV plan has three main aims: Monitor CO2 movement in the subsurface, Calibrate dynamic earth models and finally, Verify volume of stored CO2. Wide ranges of potential BMV technologies available are currently tested in CCS pilots and industrial scale projects. This paper describes how to optimize the BMV plan design by adopting a risk-based approach and how the value of information (VOI) of specific monitoring technologies needs to be assessed to meet program objectives.

Jellyfish, and: Teleology of Islands, and: Savants

Jellyfish, and: Teleology of Islands, and: Savants Jessica Johnson (bio) Jellyfish What cleanly drawn, transparent beings,lit, encased for education's sakein fluid neither flown nor flowing: your umbilically corded brain'sa ring, your world's the same on every side. Handless, eyeless,what have you to say to those of us with faces,who have faced and turned, and turned, and piled our ghostly fingerson your glass? Nothing at all—a lung,a flutter, not a thing—the thindifference betweenpushing away and letting in. [End Page 141] Teleology of Islands What is there to say, night swimmer,lodged in the kindled mechanism of the stars,black water pooling around your feet. The curved arms of the white plastic chairyou dragged from someone's summer housedraw the colder pieces of light. Breath wells up, overflowing the ribs,as blood brings heat to every restless cell,where your lonely genes are coiling and uncoiling in the dark, as the sea droplets dryto crystal on your skin, as your body goes onexpressing what it can. As the beacon sweeps around again, catching the cedarsand madrones across the bay, throwingprehistoric shadows on the wild, unfinished coast. Savants The same-faced houses are waiting for the sea.Their ledges keep binoculars, their wallshang maps of depths. In bedrooms madeto harbor light, the children wake. Fathers slouch in patio chairs, glancingfrom their sun hats toward contingent things— [End Page 142] a sail snapped full, a gull hanging on air,answering each wrinkle in the wind. The children have absorbedmore knowledge than you'd guess: the logicof the lens, the evolution of the wing. They've seenin time-lapse video, the blind, dynamic earth . . . Tonight, before sleeping, they'll conjure the tripover contour lines to the blistering deep,the sonar's ping, the reckoning place,where the seafloor departs from the map. Jessica Johnson Jessica Johnson's poems and reviews have appeared in Burnside Review, the Kenyon Review Online, Mid-American Review, the New Republic, and the Paris Review, among other journals. She lives in Portland, Oregon. Copyright © 2008 University of Nebraska Press

Diffusion in Solid Silicates: A Tool to Track Timescales of Processes Comes of Age

Understanding how processes occurring on a wide range of temporal and spatial scales combine to produce a stable dynamic Earth is a major goal of the Earth scientist. Determining durations of processes is a key step toward attaining that goal. Records of incomplete diffusive equilibration preserved in minerals are uniquely suited for the purpose of unraveling timescales of a variety of processes. Compositional zoning in minerals is like the tracks of a CD that can be decoded with suitable technology. This review discusses the causes for the limited use of this tool until recently and how these hindrances are being overcome. Examples are presented to illustrate that diffusion modeling can clock processes that last from only a few days to those that last over tens of millions of years, recorded in rocks that range in age from current volcanic eruptions to condensates from the early solar nebula.

The Effect of Using Inquiry and Multiple Representations on Introductory Geology Students' Conceptual Model Development of Coastal Eutrophication

Collegiate introductory Earth science courses are frequently terminal science courses for non-science majors. As a result these courses, such as the introductory physical geology course in this research study, are the final opportunity Earth science instructors have to support and develop student learning in the sciences. The use of inquiry-based learning (IBL) and multiple representations (e.g., physical models and information technology) has been a call for reform in science education and may be a means to reach students in introductory courses. This research tested the pedagogical coupling of IBL and multiple representations to support introductory students' conceptual model development of the complex and dynamic Earth process, eutrophication, through the evaluation of student drawings and written reports. In this research, participants from nine laboratory sections were randomly placed into experimental (IBL and multiple representations style labs) and control (workbook style labs) groups. Statistical results indicated significant (ρ < 0.05) pre-post differences in the conceptual model drawings in only the experimental group, where student performance on the reports and drawings were significantly different (ρ < 0.01) between test groups. These results indicated that the use of IBL and multiple representations had a positive impact on introductory students' conceptual model development of eutrophication.

수치해석을 이용한 우물통 기초의 관성력과 동적토압의 위상관계 분석

Dynamic earth pressure acting on geotechnical structures can be driving force or resisting force for the displacement of the structure according to the phase relation between the dynamic earth pressure and inertia force of structures. In this research, the evaluation procedure of the phase relation between the dynamic earth pressure and the inertia force was proposed. According to the procedure, numerical analyses on caisson foundation of bridges were performed and the phase relation was analyzed. The analysis results showed that the dynamic earth pressure becomes the driving force, which increases the displacement of the structure, if the displacement amplitude of ground is larger than that of structure due to the low stiffness of the ground, and the dynamic earth pressure becomes the resisting force against the displacement of the structure if the displacement amplitude of ground is smaller than that of structure due to the high stiffness of the ground.

An Efficient System for Creating Synthetic InSAR Images from Simulations

In this work we visualize tsunami and earthquake simulation results with graphics hardware acceleration. The rapid improvement in the computational power of graphics hardware and its programmability has made general computation on Graphics Processing Units (GPUs) very compelling. We generate Synthetic InSAR images using GPUs. Interference phenomena have formed the underlying theory for Interferometric Synthetic Aperture Radar (InSAR) in unveiling dynamical Earth movements. In our approach light path differences are defined by the surface values to be visualized. These path differences then modulate the lighting intensity to generate the interference patterns. We can interactively visualize surface deformation patterns by leveraging the computational power of GPUs. Our visualization method is applied to simulations of rupture fault displacements during the tsunamogenic earthquake events, which are vital to understanding the subsequent wave propagation. We also integrate the visualization results into Google Earth virtual globe to provide the geological context of the visualized regions.

Response and Modeling of Cantilever Retaining Walls Subjected to Seismic Motions

Abstract: A series of nonlinear, explicit finite difference analyses were performed to determine the dynamic response of a cantilever retaining wall subjected to earthquake motions. This article outlines the calibration and validation of the numerical model used in the analyses and comparisons are presented between the results from the finite difference analyses and results from simplified techniques for computing dynamic earth pressures and permanent wall displacement (i.e., Mononobe‐Okabe and Newmark sliding block methods). It was found that at very low levels of acceleration, the induced pressures were in general agreement with those predicted by the Mononobe‐Okabe method. However, as the accelerations increased to those expected in regions of moderate seismicity, the induced pressures are larger than those predicted by the Mononobe‐Okabe method. This deviation is attributed to the flexibility of the retaining wall system and to the observation that the driving soil wedge does not respond monolithically, but rather responds as several wedges. Additionally, it was found that the critical load case for the structural design of the wall differed from that for the global stability of the wall, contrary to the common assumption made in practice that the two load cases are the same.

Experimental investigation of EPS geofoam seismic buffers using shaking table tests

The paper reports the results of six shaking table tests using reduced-scale model walls constructed with expanded polystyrene (EPS) panels to reduce dynamic earth loads due to base shaking. The results are compared with a nominal identical rigid (control) wall constructed without a seismic buffer. The test results show that dynamic load attenuation increased with decreasing geofoam stiffness. The test with the highest buffer stiffness resulted in a 15% reduction in dynamic load and the test with lowest stiffness resulted in a 40% reduction in dynamic load compared with the control wall. The results of these experiments provide proof of the concept that EPS panels placed against rigid walls can act as seismic buffers to attenuate dynamic loads due to ground shaking (e.g. earthquake). Additional quantitative data related to load–deformation–time response, back-calculated elastic modulus values for the EPS seismic buffer configurations, dynamic interface shear properties, acceleration amplification in the backfill soil and post-excitation stress relaxation-creep behaviour are also reported.

Dynamic active earth pressure on retaining structures

Earth-retaining structures constitute an important topic of research in civil engineering, more so under earthquake conditions. For the analysis and design of retaining walls in earthquake-prone zones, accurate estimation of dynamic earth pressures is very important. Conventional methods either use pseudo-static approaches of analysis even for dynamic cases or a simple single-degree of freedom model for the retaining wall-soil system. In this paper, a simplified two-degree of freedom mass-spring-dashpot (2-DOF) dynamic model has been proposed to estimate the active earth pressure at the back of the retaining walls for translation modes of wall movement under seismic conditions. The horizontal zone of influence on dynamic earth force on the wall is estimated. Results in terms of displacement, velocity and acceleration-time history are presented for some typical cases, which show the final movement of the wall in terms of wall height, which is required for the design. The non-dimensional design chart proposed in the present study can be used to compute the total dynamic earth force on the wall under different input ground motion and backfill conditions. Finally, the results obtained have been compared with those of the available Scott model and the merits of the present results have been discussed.

The use of recycled tire chips to minimize dynamic earth pressure during compaction of backfill

The backfill areas of concrete culverts constructed in roads have been subjected to differential settlement due to poorly compacted soils. Dynamic compaction rollers cannot be fully utilized to compact the backfill soils near the culverts because the high earth pressure induced by dynamic loading frequently results in cracks in the culvert walls. In this study, two cushion materials, recycled tire chips and expanded polystyrene (EPS) boards are applied on the culvert walls in backfill areas to reduce the dynamic earth pressure induced by the compaction loading as well as to improve the characteristics of compacted soils. A numerical analysis is carried out to study the effects of the cushion materials on the stress variation with soil depth in the backfill areas. The numerical analysis shows that a cushion material with low elastic modulus and high damping ratio can effectively reduce the dynamic earth pressure. Field tests are also performed to study the performance of the two cushion materials. It is found from the field tests that the both cushion materials reduce the dynamic earth pressure acting on the culvert wall. However, the recycled tire chips are more efficient in reducing the dynamic earth pressure because of its relatively high damping ratio and low stiffness values compared to the EPS.

The Gulf Stream Voyage: Using Real Time Data in the Classroom

The recent ingression of numerous scientific research sensor networks promises the potential to improve scientific knowledge and influence many societal issues including education. Until the availability of the Internet in classrooms, students used limited and outdated data sets to learn about dynamic earth systems. Internet access creates an important opportunity for students to obtain real-time data, providing them with engaging and up-to-date information. It is essential for research scientists to consider audiences beyond their own research community and think about how and where their data can be used for educational purposes, and to create engaging, clear, concise displays of data in an effort to reach non-scientific audiences. Scientific real-time data sources displayed in a "friendly" manner have been used in classrooms for several years resulting in the discovery of several significant educational advantages including: the infusion of inquiry-based learning, fostering problem solving skills, addressing several learning styles, and student relevance. As an example of ways in which scientific real-time data can be adapted for use in the classroom, this paper describes The Gulf Stream Voyage which is an Internet-based multidisciplinary project that utilizes both real-time data and primary source materials to help guide students to discover the science and history of the Gulf Stream.

Achieving Environmental Literacy with NOAA's Observing Systems Data

The National Oceanic and Atmospheric Administration (NOAA) has significantly increased its commitment to promoting environmental literacy by adopting this effort as a strategic cross-cutting priority, forming an Office of Education and establishing an Education Council. Another of NOAA's strategic cross-cutting priorities is integrating global environmental observations and data management. NOAA possesses a vast array of observing systems that monitor oceanic, atmospheric, and terrestrial parameters. The streaming data from these systems offers broad opportunities to create real-time visualizations of dynamic Earth processes and to capture rare and spectacular events that occur on regional or global geographic scales. Making these visualizations available to and understandable by the general public is not an easy task. The potential return on investment however, is large. NOAA's Education Council realizes the educational potential that observing system data offer and has adopted Earth Observing Systems Education as a top priority. An effort is currently underway in NOAA to assess existing observing system education activities within and outside the Agency and to pilot education programs using the available streaming data. We will report on the process of assessment and on some of the pilot projects we have begun with a focus on a case study provided by the National Estuarine Research Reserve System (NERRS), a program that provides a fully operational network of integrated observing systems focused on the nation's estuaries.