Waveform Data Collection for Source Inversion Studies

1988 ◽  
Author(s):  
William N. Alexander ◽  
Raymond H. Kimmel ◽  
Lauren Malaspina
Keyword(s):  
Data Collection ◽  
Source Inversion ◽  
Waveform Data

Imaging the rupture process of recent earthquakes using backprojection of local high frequency records

2020 ◽  
Author(s):  
Ioannis Fountoulakis ◽  
Christos Evangelidis ◽  
Olga-Joan Ktenidou
Keyword(s):  
High Frequency ◽  
A Priori ◽  
Strong Motion ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Site Effect ◽  
Source Inversion ◽  
Waveform Data ◽  
Novel Approach ◽  
Spatio Temporal

<p>The seismic source spatio-temporal rupture processes of events in Japan, Greece and Turkey are imaged by backprojection of strong-motion waveforms. Normalized high-frequency (> 2Hz) S-waveforms from recordings on dense strong-motion networks are used to scan a predefined 3D source volume over time. </p><p>Backprojection is an alternative novel approach to image the spatio-temporal earthquake rupture. The method was first applied for large earthquakes at teleseismic distances, but is nowadays also used at local distances and over higher frequencies. The greatest advantage of the method is that processing is done without any a-priori constraints on the geometry, or size of the source. Thus, the spatio-temporal imaging of the rupture is feasible at higher frequencies (> 1Hz) than conventional source inversion studies, even when the examined fault geometry is complex. This high-frequency energy emitted during an earthquake is of great importance in seismic hazard assessment for certain critical infrastructures. The actual challenge in using high-frequency local recordings is to distinguish the local site effects from the true earthquake source content - otherwise, mapping the former incorrectly onto the latter limits the resolvability of the method. It is not straightforward to remove the site effect component or even to distinguish good reference stations from amid hard-soil and rock sites. In this study, the advantages and limitations of the method are explored using waveform data from well-recorded events in Japan (Kumamoto Mw7.1, 2016), Turkey (Marmara Mw6.4, 2019) and Greece (Antikythera Mw6.1, 2019). For each event and seismic array the resolution limits of the applied method are explored by performing various synthetic tests.</p>

scholarly journals Construction of fault geometry by finite-fault inversion of teleseismic data

2020 ◽  
Vol 224 (2) ◽  
pp. 1003-1014
Author(s):  
Kousuke Shimizu ◽  
Yuji Yagi ◽  
Ryo Okuwaki ◽  
Yukitoshi Fukahata
Keyword(s):  
Fault Plane ◽  
Seismic Source ◽  
Rupture Process ◽  
Inversion Method ◽  
Source Inversion ◽  
Fault Geometry ◽  
Waveform Data ◽  
Finite Fault Inversion ◽  
Finite Fault ◽  
Double Couple

SUMMARY Conventional seismic source inversion estimates the earthquake rupture process on an assumed fault plane that is determined a priori. It has been a difficult challenge to obtain the fault geometry together with the rupture process by seismic source inversion because of the nonlinearity of the inversion technique. In this study, we propose an inversion method to estimate the fault geometry and the rupture process of an earthquake from teleseismic P waveform data, through an elaboration of our previously published finite-fault inversion analysis (Shimizu et al. 2020). That method differs from conventional methods by representing slip on a fault plane with five basis double-couple components, expressed by potency density tensors, instead of two double-couple components compatible with the fault direction. Because the slip direction obtained from the potency density tensors should be compatible with the fault direction, we can obtain the fault geometry consistent with the rupture process. In practice we rely on an iterative process, first assuming a flat fault plane and then updating the fault geometry by using the information included in the obtained potency density tensors. In constructing a non-planar model-fault surface, we assume for simplicity that the fault direction changes only in either the strike or the dip direction. After checking the validity of the proposed method through synthetic tests, we applied it to the MW 7.7 2013 Balochistan, Pakistan, and MW 7.9 2015 Gorkha, Nepal, earthquakes, which occurred along geometrically complex fault systems. The modelled fault for the Balochistan earthquake is a curved strike-slip fault convex to the south-east, which is consistent with the observed surface ruptures. The modelled fault for the Gorkha earthquake is a reverse fault with a ramp-flat-ramp structure, which is also consistent with the fault geometry derived from geodetic and geological data. These results exhibit that the proposed method works well for constraining fault geometry of an earthquake.

scholarly journals Parametrization of general seismic potency and moment tensors for source inversion of seismic waveform data

2013 ◽  
Vol 194 (2) ◽  
pp. 839-843 ◽  
Author(s):  
Lupei Zhu ◽  
Yehuda Ben-Zion
Keyword(s):  
Moment Tensor ◽  
Relative Size ◽  
Seismic Moment Tensor ◽  
Source Inversion ◽  
Waveform Data ◽  
Moment Tensors ◽  
Linear Vector ◽  
Seismic Waveform ◽  
Isotropic Media ◽  
Double Couple

Abstract We decompose a general seismic potency tensor into isotropic tensor, double-couple tensor and compensated linear vector dipole using the eigenvectors and eigenvalues of the full tensor. Two dimensionless parameters are used to quantify the size of the isotropic and compensated linear vector dipole components. The parameters have well-defined finite ranges and are suited for non-linear inversions of source tensors from seismic waveform data. The decomposition and parametrization for the potency tensor are used to obtain corresponding results for a general seismic moment tensor. The relations between different parameters of the potency and moment tensors in isotropic media are derived. We also discuss appropriate specification of the relative size of different source components in inversions of seismic data.

Electron Diffraction of Wet Biological Membranes

1974 ◽  
Vol 32 ◽  
pp. 158-159
Author(s):  
S.W. Hui ◽  
D.F. Parsons
Keyword(s):  
Electron Diffraction ◽  
Data Collection ◽  
Biological Membranes ◽  
Small Areas ◽  
Electron Diffraction Technique ◽  
Electron Microscopes ◽  
Collection Time ◽  
Camera Length

The development of the hydration stages for electron microscopes has opened up the application of electron diffraction in the study of biological membranes. Membrane specimen can now be observed without the artifacts introduced during drying, fixation and staining. The advantages of the electron diffraction technique, such as the abilities to observe small areas and thin specimens, to image and to screen impurities, to vary the camera length, and to reduce data collection time are fully utilized. Here we report our pioneering work in this area.

Automated electron tomography: from data collection to image processing

1995 ◽  
Vol 53 ◽  
pp. 26-27
Author(s):  
Weiping Liu ◽  
Jennifer Fung ◽  
W.J. de Ruijter ◽  
Hans Chen ◽  
John W. Sedat ◽  
...  
Keyword(s):  
Image Processing ◽  
Data Collection ◽  
Structural Information ◽  
Imaging Technique ◽  
Electron Tomography ◽  
Ccd Camera ◽  
Automated Data Collection ◽  
Full Control ◽  
Transmission Electron ◽  
Amorphous Structures

Electron tomography is a technique where many projections of an object are collected from the transmission electron microscope (TEM), and are then used to reconstruct the object in its entirety, allowing internal structure to be viewed. As vital as is the 3-D structural information and with no other 3-D imaging technique to compete in its resolution range, electron tomography of amorphous structures has been exercised only sporadically over the last ten years. Its general lack of popularity can be attributed to the tediousness of the entire process starting from the data collection, image processing for reconstruction, and extending to the 3-D image analysis. We have been investing effort to automate all aspects of electron tomography. Our systems of data collection and tomographic image processing will be briefly described.To date, we have developed a second generation automated data collection system based on an SGI workstation (Fig. 1) (The previous version used a micro VAX). The computer takes full control of the microscope operations with its graphical menu driven environment. This is made possible by the direct digital recording of images using the CCD camera.

Productivity of Emerging Word Combinations in Toddlers With Specific Expressive Language Impairment

1997 ◽  
Vol 6 (4) ◽  
pp. 34-47 ◽  
Author(s):  
Steven H. Long ◽  
Lesley B. Olswang ◽  
Julianne Brian ◽  
Philip S. Dale
Keyword(s):  
Data Collection ◽  
Young Children ◽  
Language Impairment ◽  
Treatment Approach ◽  
Expressive Language ◽  
Semantic Consistency ◽  
Session Analysis

This study investigated whether young children with specific expressive language impairment (SELI) learn to combine words according to general positional rules or specific, grammatic relation rules. The language of 20 children with SELI (4 females, 16 males, mean age of 33 months, mean MLU of 1.34) was sampled weekly for 9 weeks. Sixteen of these children also received treatment for two-word combinations (agent+action or possessor+possession). Two different metrics were used to determine the productivity of combinatorial utterances. One metric assessed productivity based on positional consistency alone; another assessed productivity based on positional and semantic consistency. Data were analyzed session-by-session as well as cumulatively. The results suggest that these children learned to combine words according to grammatic relation rules. Results of the session-by-session analysis were less informative than those of the cumulative analysis. For children with SELI ready to make the transition to multiword utterances, these findings support a cumulative method of data collection and a treatment approach that targets specific grammatic relation rules rather than general word combinations.

Enhancing Clinical Supervision Using High-Definition Real-Time Digital Recording, Annotation, and Bluetooth Technology

2019 ◽  
Vol 4 (2) ◽  
pp. 356-362
Author(s):  
Jennifer W. Means ◽  
Casey McCaffrey
Keyword(s):  
Graduate Students ◽  
Data Collection ◽  
Real Time ◽  
Clinical Supervision ◽  
Video Recording ◽  
Advanced Technology ◽  
High Definition ◽  
Recording Technology ◽  
Self Confidence ◽  
Additional Data Collection

Purpose The use of real-time recording technology for clinical instruction allows student clinicians to more easily collect data, self-reflect, and move toward independence as supervisors continue to provide continuation of supportive methods. This article discusses how the use of high-definition real-time recording, Bluetooth technology, and embedded annotation may enhance the supervisory process. It also reports results of graduate students' perception of the benefits and satisfaction with the types of technology used. Method Survey data were collected from graduate students about their use and perceived benefits of advanced technology to support supervision during their 1st clinical experience. Results Survey results indicate that students found the use of their video recordings useful for self-evaluation, data collection, and therapy preparation. The students also perceived an increase in self-confidence through the use of the Bluetooth headsets as their supervisors could provide guidance and encouragement without interrupting the flow of their therapy sessions by entering the room to redirect them. Conclusions The use of video recording technology can provide opportunities for students to review: videos of prospective clients they will be treating, their treatment videos for self-assessment purposes, and for additional data collection. Bluetooth technology provides immediate communication between the clinical educator and the student. Students reported that the result of that communication can improve their self-confidence, perceived performance, and subsequent shift toward independence.

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