Modeling the effect of static errors in areal seismic data caused by glacial erosion over carbonate reefs

Geophysics ◽  
1984 ◽  
Vol 49 (1) ◽  
pp. 1-16
Author(s):  
Janet S. Kotcher ◽  
G. H. F. Gardner ◽  
John A. McDonald
Keyword(s):  
Data Collection ◽  
Surface Topography ◽  
Seismic Data ◽  
Structural Features ◽  
Raw Data ◽  
Areal Data ◽  
Instantaneous Phase ◽  
Reasonable Cost ◽  
Static Corrections ◽  
Northern Michigan

An effective way of exploring for structural features is by areal seismic methods. In addition to finding depth and location, the area of a structure may be determined at a reasonable cost. However, the efficacy of the areal method can be rapidly destroyed by static shifts in the seismic traces. In this paper we investigate the effect of statics on the crossed array method of areal data collection. Seismic data were collected in the northern Michigan reef trend, an area containing numerous small pinnacle reefs. The surface topography is flat, but it contains deep erosional valleys filled with glacial drift which produce time shifts in the data. The data were processed without static corrections. To predict the effect of static errors, a model was designed to produce data resembling those taken over a pinnacle reef. Seismic data were collected over this model by a method simulating the crossed array technique. Horizontal displays of the power envelope and the instantaneous phase of the migrated data were generated at a specified one‐way time, when various source and receiver dependent statics had been introduced into the raw data. The statics were designed to simulate the effect of glacial drift. If the diameter of the migration aperture is significantly larger than the distance along the source and receiver lines affected by statics, the effect on the migrated output is minimal. However, if the distance affected by statics approaches the diameter of the migration aperture, the effects are significant.

scholarly journals Integrated magnetotelluric and seismic investigation of Cenozoic graben structure near Obrzycko, Poland

2021 ◽  
Author(s):  
Adam Cygal ◽  
Michał Stefaniuk ◽  
Anna Kret
Keyword(s):  
Seismic Data ◽  
Geophysical Methods ◽  
Geological Structure ◽  
Data Sets ◽  
Low Velocity ◽  
Shallow Subsurface ◽  
Geophysical Model ◽  
Novel Approach ◽  
Loose Deposits ◽  
Static Corrections

AbstractThis article presents the results of an integrated interpretation of measurements made using Audio-Magnetotellurics and Seismic Reflection geophysical methods. The obtained results were used to build an integrated geophysical model of shallow subsurface cover consisting of Cenozoic deposits, which then formed the basis for a detailed lithological and tectonic interpretation of deeper Mesozoic sediments. Such shallow covers, consisting mainly of glacial Pleistocene deposits, are typical for central and northern Poland. This investigation concentrated on delineating the accurate geometry of Obrzycko Cenozoic graben structure filled with loose deposits, as it was of great importance to the acquisition, processing and interpretation of seismic data that was to reveal the tectonic structure of the Cretaceous and Jurassic sediments which underly the study area. Previously, some problems with estimation of seismic static corrections over similar grabens filled with more recent, low-velocity deposits were encountered. Therefore, a novel approach to estimating the exact thickness of such shallow cover consisting of low-velocity deposits was applied in the presented investigation. The study shows that some alternative geophysical data sets (such as magnetotellurics) can be used to significantly improve the imaging of geological structure in areas where seismic data are very distorted or too noisy to be used alone

Privacy-preserving raw data collection without a trusted authority for IoT

2019 ◽  
Vol 148 ◽  
pp. 340-348 ◽  
Author(s):  
Yi-Ning Liu ◽  
Yan-Ping Wang ◽  
Xiao-Fen Wang ◽  
Zhe Xia ◽  
Jing-Fang Xu
Keyword(s):  
Data Collection ◽  
Privacy Preserving ◽  
Raw Data

scholarly journals Assessment of riparian environments through semi-automated procedures for the computation of eco-morphological indicators: Preliminary results of the WEQUAL project

2019 ◽  
Vol 70 (3) ◽  
pp. 131-145 ◽  
Author(s):  
Raimondo Gallo ◽  
Gianluca Ristorto ◽  
Alex Bojeri ◽  
Nadia Zorzi ◽  
Gabriele Daglio ◽  
...  
Keyword(s):  
Data Collection ◽  
Unmanned Aircraft ◽  
Environmental Data ◽  
Shared Environment ◽  
Surface Model ◽  
Riparian Areas ◽  
Raw Data ◽  
Ecological Criteria ◽  
Web Platform ◽  
The Web

Summary The aim of WEQUAL project (WEb service centre for QUALity multidimensional design and tele-operated monitoring of Green Infrastructures) is the development of a system that is able to support a quick environmental monitoring of riparian areas subjected to the realization of new green infrastructures (GI). The Wequal’s idea is to organize a service center able to manage both the Web Platform and the whole data collection and analysis processes. Through a personal account, the final user (designer, technician, researcher) can get access to the service and requires the evaluation of alternatives GI projects. On the Web Platform, a set of algorithms runs in order to calculate, through automatic procedures, all the ecological criteria required to evaluate a quality environmental index that describes the eco-morphological value of the monitored riparian areas. For this aim, the WEQUI index was developed, which uses 15 indicators that are easy to monitor. In this paper, the approach for environmental data collection and the procedures to perform the automatic assessment of two of the ecological criteria are described. For the computation, the implemented algorithms use data including the vegetation indexes, Digital Terrain Model (DTM), Digital Surface Model (DSM) and a 3D point cloud classification. All the raw data are collected by UAVs (Unmanned Aircraft Vehicle) equipped with a 3D Lidar, multispectral camera and RGB camera. Interpreting all the raw data collected by these sensors, using a multi-attribute approach, the WEQUI index is assessed. The computed ecological index is then used to assess the riparian environmental quality at ex-ante and ex-post river stabilization works. This index, integrated with additional not-technical or not-ecological indicators such as investment required, maintenance costs or social acceptance, can be used in multicriteria analyses in order to evaluate the intervention from a wider point of view. The platform is expected to be attractive for GI designers and policy makers by providing a shared environment, which is able to integrate the method of detection and evaluation of complex indexes and a multidimensional evaluation supported by an expert guide.

scholarly journals Protein microcrystallography using synchrotron radiation

IUCrJ ◽  
2017 ◽  
Vol 4 (5) ◽  
pp. 529-539 ◽  
Author(s):  
Masaki Yamamoto ◽  
Kunio Hirata ◽  
Keitaro Yamashita ◽  
Kazuya Hasegawa ◽  
Go Ueno ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Data Collection ◽  
Diffraction Data ◽  
Structure Determination ◽  
Structural Features ◽  
X Ray ◽  
Data Collection Strategy ◽  
Technological Developments ◽  
Novel Method

The progress in X-ray microbeam applications using synchrotron radiation is beneficial to structure determination from macromolecular microcrystals such as smallin mesocrystals. However, the high intensity of microbeams causes severe radiation damage, which worsens both the statistical quality of diffraction data and their resolution, and in the worst cases results in the failure of structure determination. Even in the event of successful structure determination, site-specific damage can lead to the misinterpretation of structural features. In order to overcome this issue, technological developments in sample handling and delivery, data-collection strategy and data processing have been made. For a few crystals with dimensions of the order of 10 µm, an elegant two-step scanning strategy works well. For smaller samples, the development of a novel method to analyze multiple isomorphous microcrystals was motivated by the success of serial femtosecond crystallography with X-ray free-electron lasers. This method overcame the radiation-dose limit in diffraction data collection by using a sufficient number of crystals. Here, important technologies and the future prospects for microcrystallography are discussed.

scholarly journals Old structures revisited: Better insights from new data

2014 ◽  
Vol 70 (a1) ◽  
pp. C1692-C1692
Author(s):  
Graciela Díaz de Delgado ◽  
Belkis Ramírez V. ◽  
William Velásquez ◽  
Julio Trejo Dávila ◽  
Chun-Hsing Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Data Collection ◽  
Diffuse Scattering ◽  
Room Temperature ◽  
Structural Features ◽  
Quality Data ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Maleamic Acid ◽  
Monoclinic Cell

The need for improving the description of structural features with better quality data, at low temperature and with modern 2D detectors of certain materials, sometimes leads to surprisingly new insights into a previously reported structure. When attempting to grow single crystals of maleamic acid, good crystals of ammonium maleate, NH4(Mal), were obtained. Although the structure of this material has been reported at room temperature, in space group Pbcm with V=613.2(5) Å3[1], synchrotron data were collected at low temperature to examine the behavior of the ammonium moiety. The data collected lead to a structure better described in Pbca, a=8.9687(12), b=8.1604(8), c=16.348(2) Å, V=1196.5(2) Å3, Z=8. The refinement converged to R=0.0438, wR2=0.1156, S=1.02. An examination of the new data indicates that reflections with h odd are systematically weak but, nevertheless, present. The Ca derivative of valproic acid (a common anticonvulsant) was reported as monoclinic, C2/c, with a=16.250(8), b=18.471(17), c=7.729(7) Å, β=109.71(5)0, V=2183.97 Å3, Z=4, and R=10.94% [2]. However, data collection at room temperature and under a stream of nitrogen on several newly prepared crystals always lead to a triclinic, P-1 cell, with approximately half the volume of the reported cell. Attempts to index the dataset using the known monoclinic cell resulted in high uncertainties for the unit cell parameters and high Rint values since reflection spots showed splitting and diffuse scattering. The new cell had dimensions a=7.6995(4) Å, b=11.7444(6) Å, c=11.7708(6) Å, α=91.089(3)0, β=101.643(3)0, γ=102.041(3)0, V=1017.47(99) Å3, Z=2. Although the initial refinement was discouraging (R=0.1172, wR2=0.360, S=1.12) the analysis with PLATON indicated the presence of twining and, after considering the twin law, the refinement improved significantly (R=0.059, wR2=0.1472, S=0.99). Several examples where a new data collection resulted in interesting results will be presented.

Seismic data collection, reduction, and digitization

1961 ◽  
Vol 51 (4) ◽  
pp. 515-525
Author(s):  
B. P. Bogert
Keyword(s):  
New Jersey ◽  
Data Collection ◽  
Seismic Data ◽  
Visual Data ◽  
Recording Equipment ◽  
Field Laboratory ◽  
Set Up ◽  
Seismic Instrumentation

Abstract The facilities set up at the Bell Telephone Laboratories for seismic data collection and reduction are described. The digitization of the data so collected was carried out with existing equipment used for processing speech and visual data. We consider the seismic instrumentation and telemetry set up at the Chester Field Laboratory, Chester, New Jersey, the observation and recording equipment installed at the Murray Hill Laboratory, and finally and digitization and associated computer reduction to punched card form.

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