Multi-level fluid monitoring to understand the origin of transients

Anomalies in timeseries are frequently reported in the context of earthquake precursor studies. The state of knowledge can be summarized as follows: (i) significant anomalies exist, (ii) seismo-tectonically induced anomalies might exist, (iii) anomalies of non-tectonic origin exist and may look very similar to tectonic ones. Thus, presumably only a fraction of all reported precursors is real in the sense that they are of seismo-tectonic origin. A key problem in earthquake prediction research is to understand the origin of an anomaly and thus the separation of internal and external drivers like e.g. rainfall.&#160;&#160;State-of-the-art fluid monitoring techniques allow for a high temporal resolution compared to the low-resolution discrete sampling approach used in the last decades. A unique approach will allow to monitor ascending fluids along a vertical profile in a set of drillings from a depth of a few hundred metres to the surface. This setup can provide hints on the origin of temporal variations related to the opening of fault-valves, admixture of crustal fluids to a background mantle-flow or the release of hydrogen during fault rupturing. Gas migration velocities can thus be measured directly from the arrival times of anomalies at different depth levels. In addition, potential admixtures of mantle fluids with crustal or meteoric fluids during the ascent to the Earth&#8217;s surface can be quantified.A prototype of a multi-level gas monitoring system has been implemented at a mofette. Mofettes are gas emission sites where CO2 ascends through long-lived, narrow channels from the deep crust and possibly the Earth&#8217;s upper mantle and thus provide natural windows to magmatic processes at depth. The primary objective of our research on mofettes is to clarify physical links between fluid properties, their pathways and the relation to swarm earthquakes. The Hartou&#353;ov mofette field with an estimated daily CO2 flux between 23 and 97 t over an area of about 350,000 m2 has been chosen as a key site in the frame of the ICDP project: &#8220;Drilling the Eger Rift: Magmatic fluids driving the earthquake swarms and the deep biosphere.&#8221; It is located in the Cheb Basin, which terminates the Czech part of the Eger Rift to the West and is known for recurring earthquake swarms and mantle degassing. Gas and isotope compositions will be continuously analyzed in-situ at different depth levels (30 m, 70 m, 230 m) reached by three adjacent boreholes.

Download Full-text

Variations of gas compositions during a drilling process: A key study on the Hartoušov Mofette, Czech Republic

10.5194/egusphere-egu2020-5735 ◽

2020 ◽

Author(s):

Kyriaki Daskalopoulou ◽

Heiko Woith ◽

Martin Zimmer ◽

Samuel Niedermann ◽

Cemile D. Bağ ◽

...

Keyword(s):

Czech Republic ◽

Isotope Composition ◽

Earthquake Swarms ◽

Earthquake Activity ◽

Drilling Process ◽

Deep Biosphere ◽

Eger Rift ◽

Environmental Air ◽

A Minor ◽

Cheb Basin

The Eger Rift (Czech Republic) is an intraplate region without active volcanism but with emanations of magma-derived gases and the recurrence of mid-crustal earthquake swarms with small to intermediate magnitudes (ML < 5) in the Cheb Basin. To understand the anomalous earthquake activity and CO2 degassing, an interdisciplinary well-based observatory is built up for continuous fluid and earthquake monitoring at depth.The fluid observatory is located at the Hartou&#353;ov Mofette (Cheb Basin), an area characterized by intense mantle degassing with a subcontinental lithospheric mantle (SCLM) contribution of He that increased from 38% in 1993 to 89% in 2016. Two drillings with depths of 30 and 108 m (F1 and F2, respectively) are being monitored since August 2019 for the composition of ascending fluids. Additionally, the environmental air composition is monitored. Gas concentrations were determined in-situ at 1-min intervals, while direct sampling campaigns took place periodically and samples were analyzed for their chemical and isotope composition. Samples of gases emerging in the mofette were also collected. During this period, a third borehole (F3) with a depth of 238 m was drilled.At Hartou&#353;ov, carbon dioxide is the prevailing gas component (concentrations above 99.5%), with helium presenting a mantle origin (up to 90% considering a SCLM-type source). The atmospheric contribution is negligible, even though during drilling of F3 enrichments in atmospheric components such as Ar and N2 have been observed. An increase in both CH4 and He has been noticed in F2 (108 m borehole) at 40 m depth, whilst a decrease in He has been observed at 193 m depth in both F1 and the natural mofette. Enrichments in less soluble gases (eg. He and N2) at various depths accompanied by a minor CO2 decrease have also been noticed. Such variations may have been caused by the different solubilities of gases in aquatic environments. Moreover, a decrease in CO2 followed by a subsequent enrichment of CH4 and CxHy during the first days after the initial drilling could promote the hypothesis of the generation of microbialy derived CH4. Diurnal variations were observed for the majority of the gas components during the last phase of the F3 drilling, when the well reached a depth >200 m.This research is a part of the MoRe - &#8220;Mofette Research&#8221; project, which is included in the ICDP project &#8220;Drilling the Eger Rift: Magmatic fluids driving the earthquake swarms and the deep biosphere&#8221;). This work was supported by the DFG grant# WO 855/4-1 and BA 2207/19-1.

Download Full-text

The Global Geodetic Observing System (GGOS) – infrastructure underpinning Earth science

10.5194/egusphere-egu21-3927 ◽

2021 ◽

Author(s):

Basara Miyahara ◽

Laura Sánchez ◽

Martin Sehnal

Keyword(s):

Mass Transport ◽

Gravity Field ◽

Reference Frames ◽

Earth Science ◽

International Association ◽

Analytical Techniques ◽

Temporal Variations ◽

Core Element ◽

The Earth ◽

Surface Kinematics

The Global Geodetic Observing System (GGOS) is the contribution of Geodesy to the observation and monitoring of the Earth System. Geodesy is the science of determining and representing the shape of the Earth, its gravity field and its rotation as a function of time. A core element to reach this goal are stable and consistent geodetic reference frames, which provide the fundamental layer for the determination of time-dependent coordinates of points or objects, and for describing the motion of the Earth in space. Traditionally, geodetic reference frames have been used for surveying, mapping, and space-based positioning and navigation. With modern instrumentation and analytical techniques, Geodesy is now capable of detecting time variations ranging from large and secular scales to very small and transient deformations with increasing spatial and temporal resolution, high accuracy, and decreasing latency. GGOS has been working closely with components of International Association of Geodesy (IAG) to provide consistent and openly available observations of the spatial and temporal changes of the shape and gravity field of the Earth, as well as the temporal variations of the Earth&#8217;s rotation. These efforts make available a global picture of the surface kinematics of our planet, including the ocean, ice cover, continental water, and land surfaces, as well as estimates of mass anomalies, mass transport, and mass exchange in the System Earth. Surface kinematics and mass transport together are the key to global mass balance determination, and are an important contribution to understanding the energy budget of our planet. In order to play its vital role, GGOS has following missions; a) to provide the observations needed to monitor, map, and understand changes in the Earth&#8217;s shape, rotation, and mass distribution, b) to provide the global geodetic frame of reference that is the fundamental backbone for measuring and consistently interpreting key global change processes and for many other scientific and societal applications, c) to benefit science and society by providing the foundation upon which advances in Earth and planetary system science and applications are built. For the mission, GGOS works tighter with components of the IAG, more specifically, IAG Services, IAG Commissions and IAG Inter-Commission Committees. The IAG Services provide the infrastructure and products on which all contributions of GGOS are based, and the IAG Commissions and IAG Inter-Commission Committees provide expertise and support to address key scientific issues within GGOS. Together with the IAG components, GGOS provides the fundamental infrastructure underpinning Earth sciences and their applications.

Download Full-text

Solar and Interplanetary Dynamics (Symposium Summary)

Symposium - International Astronomical Union ◽

10.1017/s007418090006808x ◽

1980 ◽

Vol 91 ◽

pp. 547-552 ◽

Cited By ~ 1

Author(s):

M. Kuperus

Keyword(s):

Solar Atmosphere ◽

Interplanetary Medium ◽

Temporal Variations ◽

Magnetic Structures ◽

Solar Observations ◽

The Earth ◽

The Subject ◽

Physical Phenomena ◽

Made In

Solar and interplanetary dynamics comprises dynamic and plasma-physical phenomena in the solar atmosphere, the corona and the interplanetary medium in the broadest sense. In this symposium, however, one has essentially tried to restrict the subject matter to the study of the propagation of a disturbance, produced in the solar atmosphere, through the corona and the interplanetary medium. In studying solar and interplanetary dynamical phenomena we find ourselves in the unique position, with respect to other astrophysical disciplines, to be able to relate solar observations obtained with the highest possible spectral, spatial and time resolution with in situ measurements made in the interplanetary medium. It has now turned out that the two fundamental questions to be answered are:a) How does the medium in between the sun and the earth and beyond the earth's orbit, the socalled heliosphere, look like? Does a basic undisturbed heliosphere actually exist, and is one able to model its observed magnetic structures and plasma motions with their spatial and temporal variations?b) How and where in the solar atmosphere are the disturbances generated and what are the characteristic time scales, geometries and energies involved?

Download Full-text

The Estimation of Surface Albedo from DSCOVR EPIC

Remote Sensing ◽

10.3390/rs12111897 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1897

Author(s):

Qiuyue Tian ◽

Qiang Liu ◽

Jie Guang ◽

Leiku Yang ◽

Hanwei Zhang ◽

...

Keyword(s):

Temporal Resolution ◽

Surface Albedo ◽

Climate Models ◽

Three Dimensional ◽

Dimensional Structure ◽

High Temporal Resolution ◽

Observation Data ◽

Climate Change Research ◽

Narrow Channels ◽

The Earth

Surface albedo is an important parameter in climate models. The main way to obtain continuous surface albedo for large areas is satellite remote sensing. However, the existing albedo products rarely meet daily-scale requirements, which has a large impact on climate change research and rapid dynamic changes of surface analysis. The Earth Polychromatic Imaging Camera (EPIC) on the Deep Space Climate Observatory (DSCOVR) platform, which was launched into the Sun–Earth’s first Lagrange Point (L1) orbit, can provide spectral images of the entire sunlit face of Earth with 10 narrow channels (from 317 to 780 nm). As EPIC can provide high-temporal resolution data, it is beneficial to explore the feasibility of EPIC to estimate high-temporal resolution surface albedo. In this study, hourly surface albedo was calculated based on EPIC observation data. Then, the estimated albedo results were validated by ground-based observations of different land cover types. The results show that the EPIC albedo is basically consistent with the trend of the ground-based observations in the whole time series variation. The diurnal variation of the surface albedo from the hourly EPIC albedo exhibits a “U” shape curve, which has the same trend as the ground-based observations. Therefore, EPIC is helpful to enhance the temporal resolution of surface albedo to diurnal. Surfaces with a three-dimensional structure that casts shadows display the hotspot effect, producing a reflectance peak in the retro-solar direction and lower reflectance at viewing angles away from the solar direction. DSCOVR observes the entire sunlit face of the Earth, which is helpful to make up for the deficiency in the observations of traditional satellites in the hotspot direction in bidirectional reflectance distribution function (BRDF) research, and can help to improve the underestimation of albedo in the direction of hotspot observation.

Download Full-text

Variations of seismic activity caused by the Chandler Wobble

E3S Web of Conferences ◽

10.1051/e3sconf/201912703007 ◽

2019 ◽

Vol 127 ◽

pp. 03007

Author(s):

Elena Blagoveshchenskaya ◽

Evgenia Lyskova ◽

Konstantin Sannikov

Keyword(s):

Seismic Activity ◽

Statistical Parameter ◽

Specific Rotation ◽

Temporal Variations ◽

Chandler Wobble ◽

Seismic Events ◽

Slow Rotation ◽

Global Dynamic ◽

The Earth ◽

Rotation Of The Earth

The problem of the correlation of the global dynamic phenomenon “Chandler wobble” with the local dynamics in different parts of the Earth’s crust and lithosphere is wide of the solution. In this study, an attempt was made to approach the solution by analyzing the temporal variations of local seismic activity in the restricted geospace volumes (GSV) within the uniform seismoactive regions. The driver of Chandler wobble is the deep mantle – the most hard and most massive Earth’s layer, whose large inertia tensor value is able to keep up Chandler’s specific rotation of the Earth for a long time. We use the geocentric coordinate system where daily rotation is absent. In this system Chandler wobble is very slow rotation of the Earth around the current equatorial axis (the pole of which is denoted as EP14). Probably, this slow rotation can influence on the seismic events in the GSV. This influence is proposed to determine by the some statistical parameter EP14gsv that indicates the most typical position EP14 on equator when the most part of the earthquakes have occurred in the given GSV. For some geospace volumes the distribution indicates certain longitudes, where the number of seismic events is maximal or minimal.

Download Full-text

Introduction

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1978.0021 ◽

1978 ◽

Vol 288 (1355) ◽

pp. 385-386

Keyword(s):

Heat Transfer ◽

Lower Mantle ◽

Large Scale ◽

Radiative Heat ◽

Reasonable Doubt ◽

Mantle Flow ◽

Conductive Heat ◽

Mantle Material ◽

Radiative Processes ◽

The Earth

During the last fifteen years, three major developments have influenced thinking on temperature distributions within the Earth and on the origin of magmas. Perhaps the most important was the recognition that large scale plate movements which have occurred at the Earth’s surface require large scale counterflow of mantle material in the solid state. The thermal diffusivity of mantle rocks and the scale of mantle flow are such that even if the flow velocity is as low as 1 mm/a, the temperature distribution within the Earth is governed by convective, rather than conductive, transfer of heat. This has meant that the majority of thermal models of the Earth’s interior have had to be discarded as irrelevant; nearly all were based on assumptions of conductive heat transfer with a transition downwards to radiative processes. It was a feature of these models that they all gave rather high temperatures in the lower mantle; indeed, in order to keep the lower mantle below its melting temperature it was commonly necessary both to invoke radiative heat transfer and to postulate concentration of nearly all the radioactive heat production in the upper few hundred kilometres. Today the approach is very different. Conductive calculations are thought to be appropriate for only the outermost part of the mantle — that part which is incorporated in the surface plates; below the plates and at their margins, which are zones of localized up welling or downward motion, temperatures are related to the circulating motions within the mantle. It is not clear at present how deep these motions extend; beyond reasonable doubt to 700 km, but possibly over the full depth of the mantle. Remaining constraints on the distribution of heat-producing elements are largely chemical rather than physical.

Download Full-text

On the forcing mechanism for the H2-driven deep biosphere

International Journal of Astrobiology ◽

10.1017/s1473550408004205 ◽

2008 ◽

Vol 7 (2) ◽

pp. 157-167 ◽

Cited By ~ 16

Author(s):

Helge Hellevang

Keyword(s):

Hydrogen Production ◽

Ferrous Iron ◽

Plate Tectonics ◽

Large Scale ◽

Ocean Water ◽

Deep Biosphere ◽

The Earth ◽

Hydrothermal Convection ◽

Lithospheric Plates ◽

Reduced State

AbstractHeat produced in the mantle and core of the Earth by the decay of radioactive elements and mineral fusion results in large-scale mantle convection. The outer shell of the Earth that floats on the convective mantle is divided into rigid lithospheric plates. Subduction of dense cold plates into the mantle leads to plate tectonics. At divergent plate margins, heat is dissipated through hydrothermal convection cells. As ocean water is entrained into hydrothermal cells it interacts with fresh magmatic rocks and liberates ferrous iron. This iron reduces the ocean water to such an extent that it decomposes and forms hydrogen. Molecular hydrogen, as the most reduced component in the system, forms a basal component to a deep dark biosphere powered by metastable redox gradients. In this paper we review the driving force behind a hydrogen-driven deep biosphere. We present abundant observations of hydrogen produced at natural hydrothermal settings as well as in laboratory experiments. The key mineral reactions responsible for the bulk of this hydrogen production are then presented. A division of the reaction progression into an oxidized state and a reduced state is suggested. The amount of hydrogen produced is insignificant in the oxidized state whereas it becomes proportional to the amount of ferrous iron oxidized in the reduced state. The bulk of basalt-hosted aquifers are expected to reside in the oxidized state because of the low content of ferrous minerals, whereas abundant olivine in ultramafic-hosted systems is responsible for large-scale hydrogen production. Today the majority of the seafloor is basaltic. The Archean seafloor on the other hand consisted of fewer ultramafic exposures, but was dominated by ultramafic magnesium-rich lavas with a higher potential for hydrogen production than the present seafloor.

Download Full-text

ICDP project Drilling the Eger Rift – present status and further plans

10.5194/egusphere-egu2020-10122 ◽

2020 ◽

Author(s):

Torsten Dahm ◽

Tomas Fischer ◽

Heiko Woith ◽

Pavla Hrubcova ◽

Josef Vicek ◽

...

Keyword(s):

Border Region ◽

Small Scale ◽

Earthquake Swarms ◽

Fluid Composition ◽

Mass Spectrometers ◽

Monitoring Wells ◽

Eger Rift ◽

The Status ◽

Cheb Basin ◽

Natural Laboratory

Within the ICDP-Eger drilling project we are developing one of the most modern and comprehensive laboratories at depth worldwide to study the interrelations between the flow of mantle-derived fluids through the crust and their degassing at the surface, the occurrence and characteristics of crustal earthquake swarms, and the relation to the geo-biosphere. The Cheb basin located in the western Eger Rift at the Czech-German border provides an ideal natural laboratory for such a purpose. In October 2016 the ICDP proposal was accepted for complementing two existing shallow monitoring wells with five new, distributed, medium depth (<400 m) drill holes F3 and S1-S4. The resulting natural laboratory at depth will comprise five drilling sites for studying above mentioned phenomena. The F1-F3 drillings form a unique facility of three wells at one site within an active CO2 mofette of Hartou&#353;ov for continuous recordings of fluid composition and fluid flow rate, as well as for intermittent GeoBio fluid sampling. Drillings S1-S4 are planned for seismological monitoring to reach a new level of high-frequency, near source observations of earthquake swarms and related phenomena such as seismic noise and tremors generated by fluid movements. Instrumentation of the seismic wells S1-S3 will include 8-element geophone chains and a bottom-hole broadband sensor. The borehole sensors will be complemented at S1 by small-scale surface array of approximately 400 m diameter to obtain truly 3D-array configurations. If possible, broadband surface stations and other sensors will be added to each drill location. So far, we have completed drillings at sites S1, S2 and S3, with depth of 402, 480 and 400&#160;m. The drilling of S4 is planned in 2020 at one of the recently discovered Maars at the Czech-German border region. Drilling F3 was completed in September 2019 at a depth of 239&#160;m. It has reached several over-pressurized, CO2 bearing layers. The three boreholes have been connected by underground tubes system to the nearby field laboratory equipped by flowmeters and mass spectrometers allowing for long time precise monitoring of the degassing process. The S1 borehole (Landwust) will be instrumented in January 2020 by a test geophone chain allowing, along with the DAS fibre-optic cable installed behind the casing, to carry out a VSP measurement.In our presentation we provide information on the status of drillings, sensor installation and plans for the complete monitoring and data handling concept.

Download Full-text

Mantle flow in planets: lessons from sugar syrup, hair gel, milk skin and marble cake.

10.5194/egusphere-egu2020-11190 ◽

2020 ◽

Author(s):

Anne Davaille

Keyword(s):

Laboratory Experiments ◽

New Physics ◽

Dimensional Structure ◽

Short Time Scale ◽

Mantle Flow ◽

Cold Surface ◽

Mantle Dynamics ◽

Dual Nature ◽

The Earth ◽

New Phenomena

Even in the eon of supercomputers, I would claim that laboratory experiments remain an invaluable tool to investigate new phenomena and old problems, for at least 6 reasons: &#160;(1) Since they let nature solve the equations, they can explore new phenomena for which such equations do not yet exist. (2) You usually can turn around them and have a good look at their three-dimensional structure. (3) You can observe their evolution through time. (4) you can simplify the system until you understand something ! (5) On the other hand, experiments can explore ranges of parameters, or geometries, where the equations are too challenging to be solved analytically or even numerically. (6) They are at the same time fun and thought-provoking. So yes, laboratory experiments are crucial for exploring new physics, testing theories and computer codes, and show your students, colleagues and family &#171; how it works &#187;.&#160; Mantle dynamics, and thermal convection, is a good example. &#160;The emergence of mantle convection models was dictated by the failure of static, conductive, and/or radiative thermal history models to account for the mantle temperature regime, the Earth&#8217;s energy budget, and the Earth&#8217;s lateral surface motions. Convection, which transports heat by material flow, is the only other physical mechanism capable of explaining these observations. The force driving flow is gravity, whereby material lighter than its environment rises, while denser material sinks. Such density anomalies can be produced by differences in composition and/or temperature. Then, the flow patterns produced by convection also strongly depend on the way the material deforms when submitted to a force: cold surface rocks break (typical of a solid) on short time scale and distances, while hot mantle rocks creep (typical of a liquid !) on geological time scales. This dual nature of a solid and a liquid is the main source of complexity, and debate, in mantle dynamics. Modern physics calls these solid-liquid materials &#171; soft matter &#187;, and we use plenty of them in the everyday life and in the kitchen. I will show how differently mantle plumes and lithospheric plates form in honey syrup, hair gel, milk and cake. And how marble cake can help us understand mantle mixing.

Download Full-text

Results From the Insight Mission After a Year and a Half on Mars

10.5194/egusphere-egu2020-22031 ◽

2020 ◽

Author(s):

William T. Pike ◽

William Banerdt ◽

Suzanne Smrekar ◽

Philippe Lognonné ◽

Domenico Giardini ◽

...

Keyword(s):

Local Environment ◽

Atmospheric Temperature ◽

Environmental Sensors ◽

Noise Levels ◽

The Past ◽

The Earth ◽

Planetary Rotation ◽

The Magnetic Field ◽

Tectonic Origin ◽

Insight Mission

<div> <div> <div> <div> The InSight mission landed on Mars in November of 2018 and completed installation of a seismometer (SEIS) on the surface about two months later. In addition to SEIS, InSight carries a diverse geophysical observatory including a heat flow and sub-surface physical properties experiment (HP3), a geodesy (planetary rotation dynamics) experiment (RISE), and a suite of environmental sensors measuring the magnetic field and atmospheric temperature, pressure and wind (APSS). For more than a year, SEIS has been providing near-continuous seismic monitoring of Mars, with background noise levels orders of magnitude lower than that achievable on the Earth. Since installation was completed, the SEIS team has identified more than 400 events that we have not attributed to the local environment or spacecraft activity, and dozens that appear to be marsquakes of tectonic origin. We present an overview of observations by the SEIS instrument as well as a summary of other geophysical observations made by InSight during the past year and a half. </div> </div> </div> </div>

Download Full-text