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  • 1
    Type of Medium: Book
    Pages: 100 pages
    ISBN: 9789464206111
    Series Statement: European Marine Board Position Paper 26
    Language: English
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  • 2
    Online Resource
    Online Resource
    Cham :Springer International Publishing AG,
    Keywords: Natural gas-Hydrates. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (501 pages)
    Edition: 1st ed.
    ISBN: 9783030811860
    DDC: 553.285
    Language: English
    Note: Intro -- Preface -- Contents -- Editors and Contributors -- A History of Gas Hydrate Research -- 1 Gas Hydrate Research: From the Laboratory to the Pipeline -- Abstract -- 1.1 General Aspects -- 1.2 Experimental Hydrate Research -- 1.2.1 Multiscale Approach -- 1.2.2 Overview of Experimental Techniques -- 1.2.2.1 Small (Laboratory) Scale -- 1.2.2.2 Pilot Scale -- 1.3 Final Considerations -- Acknowledgements -- References -- 2 Shallow Gas Hydrates Near 64° N, Off Mid-Norway: Concerns Regarding Drilling and Production Technologies -- Abstract -- 2.1 Introduction -- 2.2 The Nyegga Gas Hydrate Location -- 2.2.1 General -- 2.2.2 The BSR -- 2.2.2.1 BSR-Related Drilling and Engineering Concerns -- 2.2.3 Complex Pockmarks -- 2.2.4 Hydrate Pingoes -- 2.2.4.1 A Qualitative Model for Hydrate Pingo Formation -- 2.2.5 Carbonate Rubble -- 2.2.6 Pockmark-, Carbonate Rubble-, and Pingo-Related Engineering Concerns -- 2.2.7 Unique Fauna -- 2.2.8 Fauna-Related Drilling and Engineering Concerns -- 2.2.9 Gas Chimneys -- 2.2.10 Gas-Chimney Related Drilling, Production, and Engineering Concerns -- 2.3 Husmus Geological Setting -- 2.3.1 General -- 2.3.2 The Shallow BSR at Husmus -- 2.3.3 Husmus-Related Drilling and Engineering Concerns -- 2.4 Ormen Lange Gas Seeping Event -- 2.4.1 Gas Seepage-Related Drilling and Engineering Concerns -- 2.5 Conclusions -- Acknowledgements -- References -- 3 Finding and Using the World's Gas Hydrates -- Abstract -- 3.1 Introduction-The Location of Gas Hydrates Beneath the Seabed -- 3.2 History of Gas Hydrate Exploration and Global Assessments of Distribution -- 3.3 The Importance of Natural Gas Hydrates -- 3.3.1 The Role of Gas Hydrates in Climate Change -- 3.3.2 Hydrates as a Control on Benthic Ecosystems -- 3.3.3 The Role of Gas Hydrates in Slope Stability -- 3.3.4 Hydrates as a Future Energy Source. , 3.3.5 Carbon Capture and Storage (CCS) in Gas Hydrate Reservoirs -- 3.4 Evidence of Submarine Gas Hydrates -- 3.4.1 Geophysical Evidence -- 3.4.2 Quantifying Hydrates Through Chemical Measurements of Cores -- 3.4.3 Borehole Logging -- 3.5 Gas Hydrates in the Solar System: Applying Lessons from Earth -- 3.6 Summary -- References -- Gas Hydrate Fundamentals -- 4 Seismic Rock Physics of Gas-Hydrate Bearing Sediments -- Abstract -- 4.1 Introduction -- 4.2 Dry-Rock Moduli -- 4.2.1 Elastic Moduli from Theoretical Models -- 4.2.2 Dry-Rock Elastic Moduli from Calibration -- 4.3 Effective-Fluid Model for Partial Saturation -- 4.4 Permeability -- 4.5 Attenuation -- 4.6 Seismic Velocities -- 4.7 Estimation of the Seismic Velocities and Attenuation -- 4.8 Conclusions -- References -- 5 Estimation of Gas Hydrates in the Pore Space of Sediments Using Inversion Methods -- Abstract -- 5.1 Introduction -- 5.2 Methods, Physical Properties and Microstructures Used for Hydrate Quantification -- 5.3 Strategy for Gas Hydrate Exploration and Quantification -- 5.4 Conclusions -- References -- 6 Electromagnetic Applications in Methane Hydrate Reservoirs -- Abstract -- 6.1 Introduction -- 6.2 Electrical Properties of Gas Hydrates -- 6.2.1 Saturation Estimates -- 6.3 Marine CSEM Principle -- 6.4 CSEM Data Interpretation -- 6.5 CSEM Instrumentation and Exploration History -- 6.5.1 Seafloor-Towed Systems -- 6.5.2 Deep-Towed Systems -- 6.5.3 Other Systems -- 6.6 Global Case Studies -- 6.7 Discussion and Conclusions -- References -- Gas Hydrate Drilling for Research and Natural Resources -- 7 Hydrate Ridge-A Gas Hydrate System in a Subduction Zone Setting -- Abstract -- 7.1 Introduction -- 7.2 Tectonic Setting -- 7.3 Stratigraphy and Structure -- 7.4 The Bottom Simulating Reflection Across Hydrate Ridge -- 7.5 Hydrate Occurrence and Distribution Within Hydrate Ridge. , 7.5.1 Hydrate Concentrations from Drilling -- 7.5.2 Inferred Hydrates and Free Gas Regionally Across Hydrate Ridge -- 7.6 Conclusions -- References -- 8 Northern Cascadia Margin Gas Hydrates-Regional Geophysical Surveying, IODP Drilling Leg 311 and Cabled Observatory Monitoring -- Abstract -- 8.1 Introduction -- 8.2 Regional Occurrences of Gas Hydrate Inferred from Remote Sensing Data -- 8.3 The Gas Hydrate Petroleum System for the Northern Cascadia Margin -- 8.4 Gas Hydrate Saturation Estimates -- 8.5 Gas Vents, Focused Fluid Flow and Shallow Gas Hydrates -- 8.6 Long-Term Observations -- 8.6.1 Gas Emissions at the Seafloor -- 8.6.2 Controlled-Source EM and Seafloor Compliance -- 8.6.3 Borehole In Situ Monitoring -- 8.7 Summary and Conclusions -- Acknowledgements -- References -- 9 Accretionary Wedge Tectonics and Gas Hydrate Distribution in the Cascadia Forearc -- Abstract -- 9.1 Introduction -- 9.2 Data -- 9.3 Results -- 9.4 Summary -- Acknowledgements -- References -- 10 Bottom Simulating Reflections Below the Blake Ridge, Western North Atlantic Margin -- Abstract -- 10.1 Geologic Setting -- 10.2 A Brief History of Blake Ridge Gas Hydrate Research -- 10.3 Blake Ridge BSR Distribution, Character and Dynamics -- 10.3.1 A Dynamic BSR on the Eastern Flank of Blake Ridge -- 10.3.2 Gas Chimneys Extending from BSRs -- 10.3.3 The Role of Sediment Waves in Gas Migration from the BSR -- 10.3.4 The Blake Ridge Diapir -- 10.4 Unanswered Questions and Future Research -- References -- 11 A Review of the Exploration, Discovery and Characterization of Highly Concentrated Gas Hydrate Accumulations in Coarse-Grained Reservoir Systems Along the Eastern Continental Margin of India -- Abstract -- 11.1 Introduction -- 11.2 India National Gas Hydrate Program-Scientific Drilling Expeditions -- 11.3 Representative Gas Hydrate Systems-Krishna-Godavari Basin. , 11.3.1 Krishna-Godavari Basin Geologic Setting -- 11.3.2 NGHP-02 Area C Gas Hydrate System -- 11.3.3 NGHP-02 Area B Gas Hydrate System -- 11.4 Summary -- Acknowledgements -- References -- 12 Ulleung Basin Gas Hydrate Drilling Expeditions, Korea: Lithologic Characteristics of Gas Hydrate-Bearing Sediments -- Abstract -- 12.1 Introduction -- 12.2 Geological Setting of the Ulleung Basin -- 12.3 Overview of the First and Second Ulleung Basin Gas Hydrate Drilling Expeditions (UBGH1 and 2) -- 12.4 Lithologic Characteristics of Gas Hydrate-Bearing Sediments in the Ulleung Basin -- 12.5 Summary -- References -- 13 Bottom Simulating Reflections in the South China Sea -- Abstract -- 13.1 Introduction -- 13.2 Geological Setting and Gas Hydrate Drilling Expeditions -- 13.3 The Characteristics of BSRs Within Various Sediment Environments -- 13.3.1 BSR and Cold Seeps in Taixinan Basin -- 13.3.2 BSRs in the Pearl River Mouth Basin -- 13.3.3 BSRs in the Qiongdongnan Basin -- 13.4 Well Log Anomalies of Different Types of Gas Hydrate -- 13.5 BSR Dynamics and Response to Fluid Migration -- 13.6 Summary -- Acknowledgements -- References -- 14 Gas Hydrate and Fluid-Related Seismic Indicators Across the Passive and Active Margins off SW Taiwan -- Abstract -- 14.1 Introduction -- 14.2 Geological Setting -- 14.3 Seismic Observations -- 14.3.1 Gas Accumulation -- 14.3.2 Fluid Migration -- 14.3.3 Presence of Gas Hydrate -- 14.4 Distribution of the Seismic Indicators and Implications for Understanding the Hydrate System -- 14.5 Summary -- References -- 15 Gas Hydrate Drilling in the Nankai Trough, Japan -- Abstract -- 15.1 Introduction -- 15.2 Discovery of Gas Hydrates and Early Expeditions in the Nankai Trough Area -- 15.3 MITI Exploratory Test Well: Nankai Trough (1999-2000) -- 15.4 METI Multi-well Exploratory Drilling Campaign and Resource Assessments. , 15.4.1 Drilling Operations and Achievements -- 15.4.2 Discovery of the Methane Hydrate Concentration Zone and Resource Assessments -- 15.5 Tests for Gas Production Undertaken in 2013 and 2017 -- 15.5.1 Gas Production Techniques and Site Selection -- 15.5.2 Drilled Boreholes and Data/Sample Acquisitions -- 15.5.3 Production Test Results and Findings -- 15.6 Other Gas Hydrate Occurrences and Resource Evaluation Results -- 15.7 Summary -- Acknowledgements -- References -- 16 Alaska North Slope Terrestrial Gas Hydrate Systems: Insights from Scientific Drilling -- Abstract -- 16.1 Introduction -- 16.2 Alaska North Slope Gas Hydrate Accumulations -- 16.3 Alaska North Slope Gas Hydrate Research Drilling Programs -- 16.3.1 Mount Elbert Gas Hydrate Stratigraphic Test Well -- 16.3.2 Iġnik Sikumi Gas Hydrate Production Test Well -- 16.3.3 Hydrate-01 Stratigraphic Test Well -- 16.4 Alaska North Slope Gas Hydrate Energy Assessments -- 16.5 Summary -- Acknowledgements -- References -- Arctic -- 17 Gas Hydrates on Alaskan Marine Margins -- Abstract -- 17.1 Introduction -- 17.2 Southeastern Alaskan Margin -- 17.3 Aleutian Arc -- 17.3.1 Eastern Aleutian Arc -- 17.3.2 Central Aleutian Arc -- 17.3.3 Western Aleutian Arc -- 17.3.4 Bering Sea -- 17.4 US Beaufort Sea -- 17.5 Summary -- Acknowledgements -- References -- 18 Gas Hydrate Related Bottom-Simulating Reflections Along the West-Svalbard Margin, Fram Strait -- Abstract -- 18.1 Introduction -- 18.2 Geological and Oceanographic Settings -- 18.2.1 Regional Tectonic Setting -- 18.2.2 Sedimentary Setting -- 18.2.3 Oceanographic Setting -- 18.3 BSR Distribution and Characteristics Within Various Sediment Types -- 18.3.1 Regional Extent of the BSRs -- 18.4 Evidence for Gas Migration from Deep and Shallow Sources -- 18.4.1 The Gas Sources -- 18.4.2 Vertical Fluid Migration Features -- 18.5 Inferred Gas Hydrate Distribution. , 18.6 BSR Dynamics and Response to Natural Changes in the Environment.
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  • 3
    In: Marine geology, Amsterdam [u.a.] : Elsevier Science, 1964, 247(2008), 1/2, Seite 46-60, 1872-6151
    In: volume:247
    In: year:2008
    In: number:1/2
    In: pages:46-60
    Description / Table of Contents: This study documents the fractal characteristics of submarine mass movement statistics and morphology within the Storegga Slide. Geomorphometric mapping is used to identify one hundred and fifteen mass movements from within the Storegga Slide scar and to extract morphological information about their headwalls. Analyses of this morphological information reveal the occurrence of spatial scale invariance within the Storegga Slide. Non-cumulative frequency-area distribution of mass movements within the Storegga Slide satisfies an inverse power law with an exponent of 1.52. The headwalls exhibit geometric similarity at a wide range of scales and the lengths of headwalls scale with mass movement areas. Composite headwalls are self-similar. One of the explanations of the observed spatial scale invariance is that the Storegga Slide is a geomorphological system that may exhibit self-organized criticality. In such a system, the input of sediment is in the form of hemipelagic sedimentation and glacial sediment deposition, and the output is represented by mass movements that are spatially scale invariant. In comparison to subaerial mass movements, the aggregate behavior of the Storegga Slide mass movements is more comparable to that of the theoretical ‘sandpile’ model. The origin of spatial scale invariance may also be linked to the retrogressive nature of the Storegga Slide. The geometric similarity in headwall morphology implies that the slope failure processes are active on a range of scales, and that modeling of slope failures and geohazard assessment can extrapolate the properties of small landslides to those of larger landslides, within the limits of power law behavior. The results also have implications for the morphological classification of submarine mass movements, because headwall shape can be used as a proxy for the type of mass movement, which can otherwise only be detected with very high resolution acoustic data that are not commonly available.
    Type of Medium: Online Resource
    ISSN: 1872-6151
    Language: English
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  • 4
    In: Geochemistry, geophysics, geosystems, Hoboken, NJ : Wiley, 2000, 10(2009), 4, 1525-2027
    In: volume:10
    In: year:2009
    In: number:4
    In: extent:9
    Description / Table of Contents: The present geological setting west of Svalbard closely parallels the situation off mid-Norway after the last glaciation, when crustal unloading by melting of ice induced very large earthquakes. Today, on the modern Svalbard margin, increasing bottom water temperatures are destabilizing marine gas hydrates, which are held in continental margin sediments consisting of interlayered contourite deposits and glacigenic debris flows. Both unloading earthquakes and hydrate failure have been identified as key factors causing several megalandslides off Norway during early Holocene deglaciation. The most prominent event was the Storegga Slide 8200 years B.P. which caused a tsunami up to 23 m high on the Faroe and Shetland islands. Here we show by numerical tsunami modeling that a smaller submarine landslide west of Svalbard, 100 m high and 130 km wide, would cause a tsunami capable of reaching northwest Europe and threatening coastal areas. A tsunami warning system based on tiltmeters would give a warning time of 1-4 h.
    Type of Medium: Online Resource
    Pages: 9 , graph. Darst
    ISSN: 1525-2027
    Language: English
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  • 5
    In: Marine geophysical research, Dordrecht [u.a.] : Springer Science + Business Media B.V., 1970, 30(2009), 3, Seite 207-214, 1573-0581
    In: volume:30
    In: year:2009
    In: number:3
    In: pages:207-214
    Description / Table of Contents: The continental margin of SW Africa is typical of a volcanic rifted margin associated with a hotspot trail characterized by a large volcanic ridge, the Walvis Ridge, defining the hotspot migration, and extensive extrusive volcanism that produced seaward-dipping reflectors (SDR). Previously unpublished seismic data show two significant anomalies of the SW African Margin when compared to other typical volcanic rifted margins: (1) Hyaloclastitic outer highs are rare, and (2) the SDR in the North dip towards the Walvis Ridge. We explain these anomalies by a major transform segment close to the centre of volcanism combined with pulsed volcanism. The Walvis Ridge represents an east-west striking extrusive centre which produced a SDR sequence. Following break-up the northern boundary of the Walvis Ridge became a left lateral transform fault. Our data support the idea that a transform fault system interacting with a ridge jump were responsible for the accretion of the São Paulo Plateau to the American plate.
    Type of Medium: Online Resource
    Pages: graph. Darst
    ISSN: 1573-0581
    Language: English
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  • 6
    In: Oceanography, Rockville, MD : The Oceanography Society, 1988, 22(2009), 1, Seite 85, 2377-617X
    In: volume:22
    In: year:2009
    In: number:1
    In: pages:85
    Type of Medium: Online Resource
    Pages: graph. Darst
    ISSN: 2377-617X
    Language: English
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  • 7
    Keywords: Oceanography ; Water ; Hydrology ; Cogeneration of electric power and heat ; Fossil fuels ; Physical geography ; Business ; Management science ; Gashydrate ; Simulation ; Sediment ; Kontinentalrand ; Methanhydrate
    Type of Medium: Book
    Pages: XXI, 514, C3 Seiten , Illustrationen, Karten
    Edition: Corrected Publication 2022
    ISBN: 3030811859 , 9783030811853
    DDC: 551.46
    Language: English
    Note: Literaturangaben
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  • 8
    Online Resource
    Online Resource
    Cham : Springer International Publishing | Cham : Imprint: Springer
    Keywords: Oceanography. ; Water. ; Fossil fuels. ; Physical geography. ; Business. ; Management science. ; Erde ; Kontinentalrand ; Gashydrate ; Offshore-Vorkommen ; Geologie ; Seismik ; Schelf ; Methanlagerstätte ; Erdgasgeologie ; Gashydrate ; Seismische Prospektion ; Vorkommen
    Description / Table of Contents: Part I. A History of gas hydrate research -- Chapter 1. Gas Hydrate Research: From the Laboratory to the Pipeline -- Chapter 2. Shallow gas hydrates near 64° N, off Mid-Norway: Concerns regarding drilling and production technologies -- Chapter 3. Finding and using the world’s gas hydrates -- Part II. Gas Hydrate Fundamentals -- Chapter 4. Seismic rock physics of gas-hydrate bearing sediments -- Chapter 5. Estimation of gas hydrates in the pore space of sediments using inversion methods -- Chapter 6. Electromagnetic applications in methane hydrate reservoirs -- Part III. Gas Hydrate Drilling for Research and Natural Resources -- Chapter 7. Hydrate Ridge - A gas hydrate system in a subduction zone setting -- Chapter 8. Northern Cascadia Margin gas hydrates – Regional geophysical surveying, IODP drilling Leg 311 and cabled observatory monitoring -- Chapter 9. Accretionary wedge tectonics and gas hydrate distribution in the Cascadia forearc -- Chapter 10. Bottom Simulating Reflections below the Blake Ridge, western North Atlantic Margin -- Chapter 11. A review of the exploration, discovery, and characterization of highly concentrated gas hydrate accumulations in coarse-grained reservoir systems along the Eastern Continental Margin of India -- Chapter 12. Ulleung Basin Gas Hydrate Drilling Expeditions, Korea: Lithologic characteristics of gas hydrate-bearing sediments -- Chapter 13. Bottom simulating reflections in the South China Sea -- Chapter 14. Gas hydrate and fluid related seismic indicators across the passive and active margins off SW Taiwan -- Chapter 15. Gas Hydrate Drilling in the Nankai Trough, Japan -- Chapter 16. Alaska North Slope Terrestrial Gas Hydrate Systems: Insights from Scientific Drilling -- Part IV -- Arctic -- Chapter 17. Gas Hydrates on Alaskan Marine Margins -- Chapter 18. Gas Hydrate related bottom-simulating reflections along the west-Svalbard margin, Fram Strait -- Chapter 19. Occurrence and distribution of bottom simulating reflections in the Barents Sea -- Chapter 20. Svyatogor Ridge - A gas hydrate system driven by crustal scale processes -- Chapter 21. Gas hydrate potential in the Kara Sea -- Part V. Greenland and Norwegian Sea -- Chapter 22. Geophysical indications of gas hydrate occurrence on the Greenland continental margins -- Chapter 23. Gas hydrates in the Norwegian Sea -- Part VI. North Atlantic. Chapter 24. U.S. Atlantic Margin Gas Hydrates -- Chapter 25. Gas Hydrates and submarine sediment mass failure: A case study from Sackville Spur, offshore Newfoundland -- Chapter 26. Bottom Simulating Reflections and Seismic Phase Reversals in the Gulf of Mexico -- Chapter 27. Insights into gas hydrate dynamics from 3D seismic data, offshore Mauritania -- Part VII. South Atlantic -- Chapter 28. Distribution and Character of Bottom Simulating Reflections in the Western Caribbean Offshore Guajira Peninsula, Colombia -- Chapter 29. Gas hydrate systems on the Brazilian continental margin -- Chapter 30. Gas hydrate on the southwest African continental margin -- Chapter 31. Shallow gas hydrates associated to pockmarks in the Northern Congo deep-sea fan, SW Africa -- Part VIII. Pacific -- Chapter 32. Gas hydrate-bearing province off eastern Sakhalin slope -- Chapter 33. Tectonic BSR Hypothesis in the Peruvian margin: A forgotten way to see marine gas hydrate systems at convergent margins -- Chapter 34. Gas hydrate and free gas along the Chilean Continental Margin -- Chapter 35. New Zealand’s Gas Hydrate Systems -- Part IX. Indic -- Chapter 36. First evidence of bottom simulation reflectors in the western Indian Ocean offshore Tanzania -- Part X. Mediterranean Sea -- Chapter 37. A Gas Hydrate System of Heterogenous Character in the Nile Deep-Sea Fan -- Part XI. Black Sea -- Chapter 38. Gas hydrate accumulations in the Black Sea -- Part XII. Lake Baikal -- Chapter 39. The position of gas hydrates in the sedimentary strata and in the geological structure of Lake Baikal -- Part XIII. Antarctic -- Chapter 40. Bottom Simulating Reflector in the western Ross Sea Antarctica -- Chapter 41. Bottom Simulating Reflectors along the Scan Basin, a deep-sea gateway between the Weddell Sea (Antarctica) and Scotia Sea -- Chapter 42. Bottom Simulating Reflections in Antarctica -- Part XIV. Where Gas Hydrate Dissociates Seafloor Microhabitats Flourish. Chapter 43. Integrating fine-scale habitat mapping and pore water analysis in cold seep research: A case study from the SW Barents Sea.
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource(XXI, 515 p. 311 illus., 296 illus. in color.)
    Edition: 1st ed. 2022.
    ISBN: 9783030811860
    Series Statement: Springer eBook Collection
    Language: English
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  • 9
    Publication Date: 2024-01-12
    Description: The Formosa Ridge cold seep is among the first documented active seeps on the northern South China Sea passive margin slope. Although this system has been the focus of scientific studies for decades, the geological factors controlling gas release are not well understood due to a lack of constraints of the subsurface structure and seepage history. Here, we use high‐resolution 3D seismic data to image stratigraphic and structural relationships associated with fluid expulsion, which provide spatio‐temporal constraints on the gas hydrate system at depth and methane seepage at modern and paleo seafloors. Gas has accumulated beneath the base of gas hydrate stability to a critical thickness, causing hydraulic fracturing, propagation of a vertical gas conduit, and morphological features (mounds) at paleo‐seafloor horizons. These mounds record multiple distinct gas migration episodes between 300,000 and 127,000 years ago, separated by periods of dormancy. Episodic seepage still seems to occur at the present day, as evidenced by two separate fronts of ascending gas imaged within the conduit. We propose that episodic seepage is associated with enhanced seafloor sedimentation. The increasing overburden leads to an increase in effective horizontal stress that exceeds the gas pressure at the top of the gas reservoir. As a result, the conduit closes off until the gas reservoir is replenished to a new (greater) critical thickness to reopen hydraulic fractures. Our results provide intricate detail of long‐term methane flux through sub‐seabed seep systems, which is important for assessing its impact on seafloor and ocean biogeochemistry.
    Description: Plain Language Summary: Gas hydrates are ice‐like compounds that form in marine sediments. They can reduce the permeability of the sediments by clogging up the pore spaces, and influence how methane gas flows through sediments and then seeps out of the seafloor. Seepage of methane into the water column plays an important role in seafloor biology and ocean chemistry. In this study, we use 3D seismic imaging to investigate the subseafloor sediments of a ridge in the South China Sea where gas is currently seeping into the ocean. Our data show, in high detail, how gas migrates upward through the sediments due to the buoyancy of gas. Our data also reveal mound structures at certain depths beneath the seafloor. We interpret that these mounds represent distinct phases in the geological past where gas was seeping out of the seafloor. This indicates that gas seepage at this ridge has switched on and off (episodically) throughout geological time. We speculate that the episodic seepage is associated with rapid seafloor sedimentation, which changes pressure conditions beneath the seafloor. Our work improves the understanding of how gas seepage processes can change on geological timescales.
    Description: Key Points: Gas has accumulated beneath the base of gas hydrate stability, causing vertical gas conduit formation and seabed mounds. Mounds imaged within the conduit record episodic seepage between 300 and 127 kyrs ago. Quiescence may be associated with enhanced seafloor sedimentation that increases effective stress at the top of the gas reservoir.
    Description: MOST
    Description: ESAS
    Description: TEC
    Description: https://doi.pangaea.de/10.1594/PANGAEA.913192
    Keywords: ddc:553.1 ; gas hydrate ; gas conduit ; hydraulic fracturing ; episodic venting ; sedimentary processes ; offshore Taiwan
    Language: English
    Type: doc-type:article
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  • 10
    Publication Date: 2023-06-16
    Description: The 1888 Ritter Island volcanic sector collapse triggered a regionally damaging tsunami. Historic eyewitness accounts allow the reconstruction of the arrival time, phase and height of the tsunami wave at multiple locations around the coast of New Guinea and New Britain. 3D seismic interpretations and sedimentological analyses indicate that the catastrophic collapse of Ritter Island was preceded by a phase of deep-seated gradual spreading within the volcanic edifice and accompanied by a submarine explosive eruption, as the volcanic conduit was cut beneath sea level. However, the potential impact of the deep-seated deformation and the explosive eruption on tsunami genesis is unclear. For the first time, it is possible to parameterise the different components of the Ritter Island collapse with 3D seismic data, and thereby test their relative contributions to the tsunami. The modelled tsunami arrival times and heights are in good agreement with the historic eyewitness accounts. Our simulations reveal that the tsunami was primarily controlled by the displacement of the water column by the collapsing cone at the subaerial-submarine boundary and that the submerged fraction of the slide mass and its mobility had only a minor effect on tsunami genesis. This indicates that the total slide volume, when incorporating the deep-seated deforming mass, is not directly scalable for the resulting tsunami height. Furthermore, the simulations show that the tsunamigenic impact of the explosive eruption energy during the Ritter Island collapse was only minor. However, this relationship may be different for other volcanogenic tsunami events with smaller slide volumes or larger magnitude eruptions, and should not be neglected in tsunami simulations and hazard assessment.
    Description: Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347
    Keywords: Tsunami simulations ; Volcanogenic tsunami genesis ; Ritter Island ; Volcanic sector collapse
    Language: English
    Type: doc-type:article
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