ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2022-09-22
    Description: Shallow earthquakes frequently disturb the hydrological and mechanical state of the subsurface, with consequences for hazard and water management. Transient post‐seismic hydrological behavior has been widely reported, suggesting that the recovery of material properties (relaxation) following ground shaking may impact groundwater fluctuations. However, the monitoring of seismic velocity variations associated with earthquake damage and hydrological variations are often done assuming that both effects are independent. In a field site prone to highly variable hydrological conditions, we disentangle the different forcing of the relative seismic velocity variations δv retrieved from a small dense seismic array in Nepal in the aftermath of the 2015 Mw 7.8 Gorkha earthquake. We successfully model transient damage effects by introducing a universal relaxation function that contains a unique maximum relaxation timescale for the main shock and the aftershocks, independent of the ground shaking levels. Next, we remove the modeled velocity from the raw data and test whether the corresponding residuals agree with a background hydrological behavior we inferred from a previously calibrated groundwater model. The fitting of the δv data with this model is improved when we introduce transient hydrological properties in the phase immediately following the main shock. This transient behavior, interpreted as an enhanced permeability in the shallow subsurface, lasts for ∼6 months and is shorter than the damage relaxation (∼1 yr). Thus, we demonstrate the capability of seismic interferometry to deconvolve transient hydrological properties after earthquakes from non‐linear mechanical recovery.
    Description: Plain Language Summary: Earthquake ground shaking damage the rocks in the subsurface of the Earth, altering their strength and their permeability. After the main shock, the rock properties slowly return to their pre‐earthquake state, but the duration of this recovery is poorly constrained. One way to investigate these time‐dependent changes is through the monitoring of seismic velocity inferred from ambient ground vibration recorded at seismic stations. Here, we constrain the evolution of seismic velocity following the large 2015 Mw 7.8 Gorkha earthquake in Nepal, in a field site characterized by seasonal groundwater fluctuations. We find that the velocity recoveries after the main shock and the aftershocks can be modeled with the same recovery timescale, independently from the initial shaking intensity. This suggests that earthquakes of different sizes activate the same geological structures and mechanisms during the recovery phase. Thanks to the unique hydrological setting of our field site and a model that links seismic velocity and groundwater level, we also show that this change of rock properties after the main shock is accompanied by a transient change in hydrological properties, an observation inferred for the first time with seismic measurement.
    Description: Key Points: We estimate a recovery time scale (〈1 yr) in seismic velocity changes after the Gorkha earthquake using ambient noise correlations. Velocity recoveries are modeled with relaxation functions characterized by a constant maximum relaxation timescale that is peak ground velocity‐independent. We highlight a transient enhanced permeability from the velocity changes in the first ∼6 months following the main shock.
    Description: GFZ HART program
    Description: https://doi.org/10.5880/GFZ.4.6.2021.002
    Description: https://doi.org/10.14470/KA7560056170
    Keywords: ddc:551.22
    Language: English
    Type: doc-type:article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2022-02-08
    Description: The following authors were omitted from the original version of this Data Descriptor: Markus Reichstein and Nicolas Vuichard. Both contributed to the code development and N. Vuichard contributed to the processing of the ERA-Interim data downscaling. Furthermore, the contribution of the co-author Frank Tiedemann was re-evaluated relative to the colleague Corinna Rebmann, both working at the same sites, and based on this re-evaluation a substitution in the co-author list is implemented (with Rebmann replacing Tiedemann). Finally, two affiliations were listed incorrectly and are corrected here (entries 190 and 193). The author list and affiliations have been amended to address these omissions in both the HTML and PDF versions. © 2021, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
    Language: English
    Type: info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2022-03-29
    Description: Although submarine landslides have been studied for decades, a persistent challenge is the integration of diverse geoscientific datasets to characterize failure processes. We present a core‐log‐seismic integration study of the Tuaheni Landslide Complex to investigate intact sediments beneath the undeformed seafloor as well as post‐failure landslide deposits. Beneath the undeformed seafloor are coherent reflections underlain by a weakly‐reflective and chaotic seismic unit. This chaotic unit is characterized by variable shear strength that correlates with density fluctuations. The basal shear zone of the Tuaheni landslide likely exploited one (or more) of the low shear strength intervals. Within the landslide deposits is a widespread “Intra‐debris Reflector”, previously interpreted as the landslide's basal shear zone. This reflector is a subtle impedance drop around the boundary between upper and lower landslide units. However, there is no pronounced shear strength change across this horizon. Rather, there is a pronounced reduction in shear strength ∼10–15 m above the Intra‐debris Reflector that presumably represents an induced weak layer that developed during failure. Free gas accumulates beneath some regions of the landslide and is widespread deeper in the sedimentary sequence, suggesting that free gas may have played a role in pre‐conditioning the slope to failure. Additional pre‐conditioning or failure triggers could have been seismic shaking and associated transient fluid pressure. Our study underscores the importance of detailed core‐log‐seismic integration approaches for investigating basal shear zone development in submarine landslides.
    Description: Plain Language Summary: Submarine landslides move enormous amounts of sediment across the seafloor and have the potential to generate damaging tsunamis. To understand how submarine landslides develop, we need to be able to image and sample beneath the seafloor in regions where landslides have occurred. To image beneath the seafloor we generate sound waves in the ocean and record reflections from those waves, enabling us to produce “seismic images” of sediment layers and structures beneath the seafloor. We then use scientific drilling to sample the sediment layers and measure physical properties. In this study, we combine seismic images and drilling results to investigate a submarine landslide east of New Zealand's North Island. Drilling next to the landslide revealed a ∼25 m‐thick layer of sediment (from ∼75–95 m below the seafloor) that has strong variations in sediment strength and density. We infer that intervals of relatively low strength within this layer developed into the main sliding surface of the landslide. Additionally, results from within the landslide suggest that the process of landslide emplacement has induced a zone of weak sediments closer to the seafloor. Our study demonstrates how combining seismic images and drilling data helps to understand submarine landslide processes.
    Description: Key Points: We integrate scientific drilling data with seismic reflection data to investigate the submarine Tuaheni Landslide Complex. Basal shear zone of the landslide likely exploited a relatively low shear strength interval within an older (buried) mass transport deposit. Landslide emplacement seems to have induced an additional weak zone that is shallower than the interpreted base of the landslide deposit.
    Description: Marsden Fund (Royal Society of New Zealand Marsden Fund) http://dx.doi.org/10.13039/501100009193
    Description: European Consortium for Ocean Research Drilling
    Description: International Ocean Drilling Program, Science Support Program
    Description: New Zealand Ministry for Business Innovation and Employment
    Description: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659
    Description: https://doi.pangaea.de/10.1594/PANGAEA.928073
    Keywords: ddc:622.15 ; ddc:551
    Language: English
    Type: doc-type:article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publication Date: 2022-10-31
    Description: Dataset: Soil physicochemical properties
    Description: Nine coastal wetland soil cores (150cm) collected in June 2018 from Barataria Bay, Louisiana were analyzed for biogeochemical properties, organic matter fractionation, and stable isotope signatures For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/840246
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1635837
    Keywords: Soil organic matter ; Coastal wetlands ; Sea level rise ; Wetland submergence
    Repository Name: Woods Hole Open Access Server
    Type: Dataset
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publication Date: 2022-10-31
    Description: Dataset: Nutrients
    Description: Nine coastal wetland soil cores (150cm) that were collected in June 2018 from Barataria Bay, Louisiana were analyzed for nutrients For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/840293
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1635837
    Keywords: Nutrients ; Barataria Bay ; Coastal wetlands ; Wetland submergence ; Sea level rise
    Repository Name: Woods Hole Open Access Server
    Type: Dataset
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2022-10-31
    Description: Dataset: Core Fluorescent Indicators, March and November 2017
    Description: Core samples were collected from three different transects in South Wilkinson Bay in the Northeast portion of Barataria Bay, Louisiana in March and November, 2018. Samples were then analyzed for fluorescence and other physical indicators. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/859759
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1636052
    Keywords: Fluorescence ; Coastal wetlands ; Carbon ; Subsidence
    Repository Name: Woods Hole Open Access Server
    Type: Dataset
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    facet.materialart.
    Unknown
    Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu
    Publication Date: 2022-10-31
    Description: Dataset: Gene Abundance
    Description: Nine coastal wetland soil cores (150cm) collected in June 2018 from Barataria Bay, Louisiana were analyzed for microbial gene abundance For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/840278
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1635837
    Keywords: Gene abudance ; Microbial activity ; Barataria Bay ; Wetland submergence ; Coastal wetlands ; Soil organic matter
    Repository Name: Woods Hole Open Access Server
    Type: Dataset
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2022-10-31
    Description: Dataset: Core Fluorescent Indicators Sept 2018
    Description: Triplicate core samples were collected at three different distances at sites on the North, East, South, and West sides of a protected island in South Wilkinson Bay in the Northeast portion of Barataria Bay, Louisiana in September 2018. Samples were then analyzed for fluorescence and other physical indicators. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/855277
    Description: NSF Division of Ocean Sciences (NSF OCE) OCE-1636052
    Keywords: Fluorescence ; Coastal wetlands ; Carbon ; Subsidence
    Repository Name: Woods Hole Open Access Server
    Type: Dataset
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2022-05-26
    Description: Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 101(6), (2020): E897-E904, doi:10.1175/BAMS-D-19-0047.1.
    Description: Over the past 15 years, numerous studies have suggested that the sinking branches of Earth’s Hadley circulation and the associated subtropical dry zones have shifted poleward over the late twentieth century and early twenty-first century. Early estimates of this tropical widening from satellite observations and reanalyses varied from 0.25° to 3° latitude per decade, while estimates from global climate models show widening at the lower end of the observed range. In 2016, two working groups, the U.S. Climate Variability and Predictability (CLIVAR) working group on the Changing Width of the Tropical Belt and the International Space Science Institute (ISSI) Tropical Width Diagnostics Intercomparison Project, were formed to synthesize current understanding of the magnitude, causes, and impacts of the recent tropical widening evident in observations. These working groups concluded that the large rates of observed tropical widening noted by earlier studies resulted from their use of metrics that poorly capture changes in the Hadley circulation, or from the use of reanalyses that contained spurious trends. Accounting for these issues reduces the range of observed expansion rates to 0.25°–0.5° latitude decade‒1—within the range from model simulations. Models indicate that most of the recent Northern Hemisphere tropical widening is consistent with natural variability, whereas increasing greenhouse gases and decreasing stratospheric ozone likely played an important role in Southern Hemisphere widening. Whatever the cause or rate of expansion, understanding the regional impacts of tropical widening requires additional work, as different forcings can produce different regional patterns of widening.
    Description: We thank U.S. CLIVAR and ISSI for funding the two working groups. We thank all members of the working groups for helpful discussions, and the U.S. CLIVAR and ISSI offices and their sponsoring agencies (NASA, NOAA, NSF, DOE, ESA, Swiss Confederation, Swiss Academy of Sciences, and University of Bern) for supporting these groups and activities.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2022-10-20
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Blevins, M. G., Allen, H. L., Colson, B. C., Cook, A.-M., Greenbaum, A. Z., Hemami, S. S., Hollmann, J., Kim, E., LaRocca, A. A., Markoski, K. A., Miraglia, P., Mott, V. L., Robberson, W. M., Santos, J. A., Sprachman, M. M., Swierk, P., Tate, S., Witinski, M. F., Kratchman, L. B., & Michel, A. P. M. Field-portable microplastic sensing in aqueous environments: a perspective on emerging techniques. Sensors, 21(10), (2021): 3532, https://doi.org/10.3390/s21103532.
    Description: Microplastics (MPs) have been found in aqueous environments ranging from rural ponds and lakes to the deep ocean. Despite the ubiquity of MPs, our ability to characterize MPs in the environment is limited by the lack of technologies for rapidly and accurately identifying and quantifying MPs. Although standards exist for MP sample collection and preparation, methods of MP analysis vary considerably and produce data with a broad range of data content and quality. The need for extensive analysis-specific sample preparation in current technology approaches has hindered the emergence of a single technique which can operate on aqueous samples in the field, rather than on dried laboratory preparations. In this perspective, we consider MP measurement technologies with a focus on both their eventual field-deployability and their respective data products (e.g., MP particle count, size, and/or polymer type). We present preliminary demonstrations of several prospective MP measurement techniques, with an eye towards developing a solution or solutions that can transition from the laboratory to the field. Specifically, experimental results are presented from multiple prototype systems that measure various physical properties of MPs: pyrolysis-differential mobility spectroscopy, short-wave infrared imaging, aqueous Nile Red labeling and counting, acoustophoresis, ultrasound, impedance spectroscopy, and dielectrophoresis.
    Description: We greatly thank our funding agencies: Gerstner Philanthropies (to A.P.M.M.), the Richard Saltonstall Charitable Foundation (to A.P.M.M.), and the Wallace Research Foundation (to A.P.M.M. and S.S.H.). Funding for M.G.B. was provided by a Draper Fellowship and to B.C.C. by an MIT Martin Fellowship. Draper thanks EPA region 9 for their partnership and support through a Cooperative Research and Development Agreement, an industry/government agreement regarding funding and personnel contributions of time and expertise.
    Keywords: Microplastics ; Plastic pollution ; Sensors ; Analytical chemistry ; Environment ; Water ; Ocean ; Marine pollution ; Polymers ; Freshwater ; Aqueous solutions
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...