12 documents found in 356ms
# 1
Ritter, Malte C. • Rosenau, Matthias • Oncken, Onno
Abstract: This dataset is supplementary material to the article of Ritter et al. (2017). In this article, the similarity of fault propagation work in analogue sandbox experiments to natural fault networks is investigated through measurements in a strike-slip sandbox and in a ring-shear-tester. The transient shear strength of the samples is measured for different fault lengths and from this the work is determined. For a detailed description of the procedure and the set-up please see Ritter et al. (2017). The data available in this supplementary publication are:• For the strike-slip experiments three video sequences of the deformation together with the evolution of boundary force for fault lengths of 20 cm, 30 cm and 40 cm. The videos show the curl of the deformation field, determined by Digital Image Correlation of top-view video images. These files are in AVI-format and included in the zip folder 2017-005-Ritter-movies.zip.• A folder containing force vs. displacement measurements for each experiment (2017-005-Ritter-forces.zip). These are 25 ASCII-files that contain two columns of numerical data: the first column is the displacement in meter; the second column is the corresponding force in newton. The files are named according to the following pattern: <fault length in meter>_<experiment number>.asc• A Matlab script to load the force files and calculate the work. This file is called “plotwork.m” and calls the Matlab function “work.m”, which does the actual calculations. These files have been tested in Matlab version 2012b. The surface deformation data are available upon request.
# 2
Ritter, Malte Christian • Santimano, Tasca • Rosenau, Matthias • Leever, Karen • Oncken, Onno
Abstract: This dataset is supplementary to the article of Ritter et al. (2017). In this article, a new experimental device is presented that facilitates precise measurements of boundary forces and surface deformation at high temporal and spatial resolution. This supplementary dataset contains the measurement data from two experiments carried out in this new experimental device: one experiment of an accretionary critical wedge and one of Riedel-type strike-slip deformation. For a detailed description of the set-up and an analysis of the data, please see Ritter et al. (2017). The data available for either experiment are:• A video showing deformation in top view together with the evolution of boundary force. This file is in AVI-format.• A time-series of 2D vector fields describing the surface deformation. These vector fields were obtained from top-view video images of the respective experiment by means of digital image correlation (DIC). Each vector field is contained in a separate file; the files are consecutively numbered. The vector fields are stored in *.mat-files that can be opened using e.g. the software Matlab or the freely available GNU Octave. They take the form of Matlab structure arrays and are compatible to the PIVmat-toolbox by Moisy (2016) that is freely available. The most important fields of the structure are: x and y, that are vectors spanning a coordinate system, and vx and vy, which are arrays containing the actual vector components in x- and y-direction, respectively.• A file containing the measurements of the boundary force applied to drive deformation. This file is also a *.mat-file, containing a structure F with fields force, velocity and position. These fields are vectors describing the force applied by the indenter, the indenter velocity and the indenter position
# 3
Souloumiac, Pauline • Maillot, Bertrand • Herbert, Justin W. • McBeck, Jessica A. • Cooke, Michele L.
Abstract: The data set includes photos, force measurements, and incremental displacement fields captured in experiment E240 run at the physical modeling laboratory (GEC) at the Université de Cergy-Pontoise. We built the accretionary wedge using a novel sedimentation device [Maillot, 2013] that distributes sand in planar layers and creates homogeneous sandpacks. We include photos of the side of the accretionary wedge in a zipped folder (E240_sideviews). Throughout the experiment, we took a photo every 5 seconds. We include the incremental displacement fields calculated from digital image correlation of sequential photos [Adam et al., 2005; Hoth, 2005] as matlab (.mat) files in a zipped folder (E240_001-062_DIC_MAT), and as .csv files in a zipped folder (E240_001-062_DIC_CSV). The .mat and .csv files are numbered to indicate which sequential photo pairs were used to calculate the displacements. For example, E240_001-062_0001_CSV.csv (and E240_001-062_0001.mat) contain the incremental displacements between photo 001.jpg and 002.jpg. All files are included in a single zip folder (Souloumiac-et-al-2017-supplementary-datasets.zip). The matlab files include the variable arrays x, y, u, v, which are the x and y coordinates (in pixels relative to the upper left corner of the image), and the horizontal (u) and vertical (v) incremental displacement fields (in pixels), respectively. The .csv files contain four columns of data with the x and y coordinates in the first two columns, and the horizontal (u) and vertical (v) displacements in the last two columns. We include force measurements in a text file (E240_force_corrected) with two columns: the first column is the total displacement of the backwall in millimeters at the time that the force measurement was recorded, and the second column is the normal force exerted on the backwall, in Newtons. The force measurements are calculated from measurements of strain gauges mounted on a wall of the sand box (i.e., the backwall) [e.g., Souloumiac et al., 2012].
# 4
Verberne, Berend Antonie • Chen, Jianye • Pennock, Gillian
Abstract: The largest magnitude earthquakes nucleate at depths near the base of the seismogenic zone, near the transition from velocity weakening frictional slip to velocity strengthening ductile flow. However, the mechanisms controlling this transition, and relevant to earthquake nucleation, remain poorly understood. Here we present data from experiments investigating the effect of slip rate on the mechanical properties and microstructure development of simulated calcite fault gouge sheared at ~550°C, close to the transition from (unstable) velocity weakening to (stable) velocity strengthening behaviour, reported by Verberne et al. (2015). We conducted experiments at a constant effective normal stress (σneff) of 50 MPa, as well as σneff-stepping tests employing 20 MPa ≤ σneff ≤ 140 MPa, at constant sliding velocities (v) of 0.1, 1, 10, or 100 µm/s. Samples sheared at v ≥ 1 µm/s showed a microstructure characterized by a single, 30 to 40 μm wide boundary shear, as well as a linear correlation of shear strength (τ) with σneff. Remarkably, electron backscatter diffraction mapping of polygonal shear band grains demonstrated a crystallographic preferred orientation. By contrast, samples sheared at 0.1 µm/s showed a microstructure characterized by homogeneous deformation and plastic flow, as well as a flattening-off of the τ-σneff curve. Our results point to a strain rate dependent frictional-to-viscous transition in simulated calcite fault gouge, and have important implications for the processes controlling earthquake nucleation at the base of the seismogenic zone.
# 5
Del Bello, Elisabetta • Taddeucci, Jacopo • Scarlato, Piergiorgio • Giacalone, Emanuele
Abstract: This data publication includes particle size distribution data of natural volcanic ash samples used as starting material for laboratory experiments simulating the aggregation/disaggregation of colliding volcanic ash particles. Full details of the experimental method can be found in Del Bello et. al. (2015) and in the data description file provided here. Here we report raw particle size distribution data obtained through separation analysis. Two types of volcanic ash were analysed: i) andesitic ash from the Sakurajima volcano (Japan), collected from July 2013 deposits (named Sak sample); ii) phonolitic ash collected from the basal fallout layer of the ~10 ka old Pomici Principali eruptive unit [Di Vito et al., 1999]) of the Campi Flegrei (named Ppa). For both compositions, 3 different starting materials were obtained by hand sieving the natural samples into three main particle size classes: (i) <32 μm, (ii) 32–63 μm, and (iii) 63–90 μm. For the phonolitic composition Ppa two additional starting materials were obtained by mixing the <32 μm and the 32–63 μm classes in known proportions. For each starting material, the grain size distribution of the sample was measured by a multiwavelength separation analyzer (LUMIReader®, https://www.lum-gmbh.com/lumireader_en.html). This device measures space and time resolved profiles of the transmitted light across the water-diluted sample (5% solid content) during sedimentation of particles. The cumulative volume-weighted particle size distribution is obtained from the extinction profiles using the multi-wavelength Particle size Analyser modulus (PSA). Details on the sample preparation procedure can be found in Detloff et al. (2006). For each measurement performed (see Table 1), a pdf file and a excel file are provided. The pdf file lists the analysis summary, including a description of the analysis settings and conditions, materials used, and distribution model adopted for the fit. It also provides graphs of the obtained volume weighted cumulative grain size distribution, and of the measured transmission profiles for each wavelength (870 nm, 630 nm and 470 nm, respectively). The Excel (*.xlsx format) file include 4 datasheets, listing the results (sheet name ending *_R) and the fit data (sheet names ending *_F01,*_F02, *_F03) obtained for the different instrument wavelength. In each datasheet the following data are listed in the columns: particle grain size (x3 in µm), volume weighted distribution (Q3(x) in %), Martin diameter (x3m in µm), volume weighted density distribution (q3(x) in 1/µm). The fit datasheets also include information on the fit such as distribution model used and distribution parameters (quantiles, median, standard deviation, span, etc..). A full list of the files included is given in List_of_files_DelBello et al 2017.pdf.
Measurement name Sample type Size class (µm)* Ppamag32_01 Phonolite (Ppa) 32-63 Ppamag32_03 Phonolite (Ppa) 32-63 Ppamag32_61 Phonolite (Ppa) 32-63Ppamag64_01 Phonolite (Ppa) 63-90Ppamin32_00 Phonolite (Ppa) <32 Ppamin32_02 Phonolite (Ppa) <32 Ppamin32_35 Phonolite (Ppa) <32 Ppamix32_02 Phonolite (Ppa) <32 + 32-63 (1:1) Ppamix32_03 Phonolite (Ppa) <32 + 32-63 (1:10)Ppamix32_04 Phonolite (Ppa) <32 + 32-63 (1:5) Ppamix32_05 Phonolite (Ppa) <32 + 32-63 (1:2) Ppamix32_06 Phonolite (Ppa) <32 + 32-63 (1:1) Ppamix32_70 Phonolite (Ppa) <32 + 32-63 (1:10) Ppamix32_71 Phonolite (Ppa) <32 + 32-63 (1:5) Ppamix32_72 Phonolite (Ppa) <32 + 32-63 (1:2) Ppamix32_73 Phonolite (Ppa) <32 + 32-63 (1:1) Ppamix63_02 Phonolite (Ppa) <32 + 63-90 (1:1) Ppatotal_01 Phonolite (Ppa) total Sakmag32_02 Andesite (Sak) 32-63 Sakmag63_01 Andesite (Sak) 32-63 Sakmag90_01 Andesite (Sak) 63-90 Sakmin32_01 Andesite (Sak) <32 Sakmin32_02 Andesite (Sak) <32 Saktotal_01 Andesite (Sak) total Table 1. List of particle size characterization measurements included in this dataset. *When mixed sample are used, the respective weight proportion of the component classes used are reported in brackets.
# 6
Quinteros, Javier
Abstract: This service provides routing information for distributed data centres, in the case where multiple different seismic data centres offer access to data and products using compatible types of services. Examples of the data and product objects are seismic timeseries waveforms, station inventory, or quality parameters from the waveforms. The European Integrated Data Archive (EIDA) is an example of a set of distributed data centres (the EIDA „nodes“). EIDA have offered Arclink and Seedlink services for many years, and now offers FDSN web services, for accessing their holdings. In keeping with the distributed nature of EIDA, these services could run at different nodes or elsewhere; even on computers from normal users. Depending on the type of service, these may only provide information about a reduced subset of all the available waveforms. To be effective, the Routing Service must know the locations of all services integrated into a system and serve this information in order to help the development of smart clients and/or services at a higher level, which can offer the user an integrated view of the entire system (EIDA), hiding the complexity of its internal structure. The service is intended to be open and able to be queried by anyone without the need of credentials or authentication.
# 7
Williams, Jack • Toy, Virginia • Massiot, Cecile • McNamara, David
Abstract: The orientations and densities of fractures in the foliated hanging-wall of the Alpine Fault provide insights into the role of a mechanical anisotropy in upper crustal deformation, and the extent to which existing models of fault zone structure can be applied to active plate-boundary faults. Three datasets were used to quantify fracture damage at different distances from the Alpine Fault principal slip zones (PSZs): (1) X-ray computed tomography (CT) images of drill-core collected within 25 m of the PSZs during the first phase of the Deep Fault Drilling Project that were reoriented with respect to borehole televiewer (BHTV) images, (2) field measurements from creek sections at <500 m from the PSZs, and (3) CT images of oriented drill-core collected during the Amethyst Hydro Project at distances of ~500-1400 m from the PSZs. Results show that within 160 m of the PSZs in foliated cataclasites and ultramylonites, gouge-filled fractures exhibit a wide range of orientations. At these distances, fractures are interpreted to form at high confining pressures and/or in rocks that have a weak mechanical anisotropy. Conversley, at distances greater than 160 m from the PSZs, fractures are typically open and subparallel to the mylonitic foliation or schistosity, implying that fracturing occurred at low confining pressures and/or in rocks that are mechanically anisotropic. Fracture density is similar across the ~500 m width of the hanging-wall datasets, indicating that the Alpine Fault does not have a typical “damage zone” defined by decreasing fracture density with distance. Instead, we conclude that the ~160 m-wide zone of intensive gouge-filled fractures provides the best estimate for the width of brittle fault-related damage. This estimate is similar to the 60-200 m wide Alpine Fault low-velocity zone detected through fault zone guided waves, indicating that a majority of its brittle damage occurs within its hanging-wall. The data provided here include CT scan 'core logs' for drill-core from both boreholes of the first phase of the Deep Fault Drilling Project (DFDP-1A and DFDP-1B) and from the Amethyst Hydro Project (AHP), the code to generate 'unrolled' CT images (which is to be run on imageJ), and an overview image of the integration of unrolled DFDP-1B CT images and BHTV images (DFDP-1B_BHTV-CT-Intergration.pdf). The header for the scan log images indicate 'core run-core section-upper depth-lower depth' for DFDP and 'borehole-core run-core section-upper depth-lower depth' for AHP boreholes. CT scan core logs cover the depth range 67.5-91.1 m in DFDP-1A drill-core and all of DFDP-1B drill-core. A classification of fracture type is given in Williams et al (2016). For DFDP-1 CT scan logs, title of each page labelled by: core run - core section - depth range. For AHP CT scan log, header of each page gives: borehole - core run - core section - depth. These are supplementary material to Williams et al. (submitted), in which a methodology for matching unrolled CT and BHTV images is given in Appendix A.
# 8
Stromeyer, Dietrich • Heidbach, Oliver
Abstract: For the visualization and analysis of the stress field from 4D thermo-hydro-mechanical (THM) numerical model results two main technical steps are necessary. First, one has to derive from the six independent components of the stress tensor scalar and vector values such as the ori-entation and magnitude of the maximum and minimum horizontal stress, stress ratios, differential stress. It is also of great interest to display e.g. the normal and shear stress with respect to an arbitrarily given surface. Second, an appropriate geometry has to be given such as cross sections, profile e.g. for borehole pathways or surfaces on which the model results and further derived values are interpolated. This includes the three field variables temperature, pore pressure and the displacement vector. To facilitate and automate these steps the add-on GeoStress for the professional visualization software Tecplot 360 EX has been programmed. Besides the aforementioned values derived from the stress tensor the tool also allows to calculate the values of Coulomb Failure Stress (CFS), Slip and Dilation tendency (ST and DT) and Fracture Potential (FP). GeoStress also estimates kinematic variables such as horizontal slip, dip slip, rake vector of faults that are implemented as contact surfaces in the geomechanical-numerical model as well as the true vertical depth. Furthermore, the add-on can export surfaces and polylines and map on these all availble stress values. The technical report describes the technical details of the visualization tool, its usage and ex-emplifies its application using the results of a 3D example of a geomechanical-numerical model of the stress field. The numerical solution is achieved with the finite element software Abaqus version 6.11. It also presents a number of special features of Tecplot 360 EX in combination with GeoStress that allow a professional and efficient analysis. The Add-on and a number of example and input files are provided at http://doi.org/10.5880/wsm.2017.001.
# 9
Ziegler, Moritz • Heidbach, Oliver
Abstract: The distribution of data records for the maximum horizontal stress orientation SHmax in the Earth’s crust is sparse and very unequally. In order to analyse the stress pattern and its wavelength or to predict the mean SHmax orientation on a regular grid, statistical interpolation as conducted e.g. by Coblentz and Richardson (1995), Müller et al. (2003), Heidbach and Höhne (2008), Heidbach et al. (2010) or Reiter et al. (2014) is necessary. Based on their work we wrote the Matlab® script Stress2Grid that provides several features to analyse the mean SHmax pattern. The script facilitates and speeds up this analysis and extends the functionality compared to aforementioned publications. The script and a number of example and input files are provided at http://doi.org/10.5880/wsm.2017.002. The script provides two different concepts to calculate the mean SHmax orientation on a regular grid. The first is using a fixed search radius around the grid point and computes the mean SHmax orientation if sufficient data records are within the search radius. The larger the search radius the larger is the filtered wavelength of the stress pattern. The second approach is using variable search radii and determines the search radius for which the variance of the mean SHmax orientation is below a given threshold. This approach delivers mean SHmax orientations with a user-defined degree of reliability. It resolves local stress perturbations and is not available in areas with conflicting information that result in a large variance. Furthermore, the script can also estimate the deviation between plate motion direction and the mean SHmax orientation.
# 10
Victor, Pia • Ziegenhagen, Thomas • Oncken, Onno • Gonzalez, Gabriel
Abstract: IPOC Creep is an array of 11 creepmeters installed along 4 active segments oft eh Atacama Fault Zone in Northern Chile. Installation of instruments started in 2008 within the framework of the Integrated Plate-boundary Observatory Chile (IPOC) and was completed in 2011. All installations are designed by the authors and follow a general concept, but are adapted to each site specifically. All the installed instruments use solid 12 mm thick invar rods as length standards, which are firmly attached to a concrete foundation in the hanging wall of the fault and pass through a PVC pipe to the footwall side of the fault where it is fixed to another concrete foundation. The creepmeters are buried at a depth of 30 - 70 cm, in order to increase the signal-to-noise ratio. We use a LVDT (linear variable differential transformer) with a range of 50 mm to monitor the relative displacement of the free end of the rod relative to the fixation point. Displacement is measured as voltage change and stored on a data logger with a sampling rate of 1/min (2008-2011 and 2/min (since 2011). Temperature at the rod is continuously measured with the same sampling rate to correct for thermal expansion and contraction of the length standard. The length of the instrument is dependent on the geometry at each site and ranges between 2 and 9 m. More specific information on each site can be found on http://www.ipoc-network.org/index.php/observatory/creepmeter.html . The Data is stored as time series since the initial start of operation of each creepmeter until July 2016. Data format is asci and contains 4 columns: 1st column Date[D.M.Y] 2nd column Time [HH:MM:SS] 3rd column ReferenceSensor[V]The reference signal is a steady signal of 1V and fluctuations indicate general voltage fluctuations in the setup. By normalizing to the reference signal it is possible to correct for these voltage changes. 4th column CreepSensor[V]The measured voltage of the CreepSensor is linearly proportional to the actual displacement. It can be converted to micrometers as follows: Displacement(µm) = (CreepSensor(t2)[V] - CreepSensor(t1)[V]) * 10000.
spinning wheel Loading next page