scholarly journals Rapid 3D Seismic Source Inversion Using Windows Azure and Amazon EC2

2011 ◽  
Author(s):  
Vedaprakash Subramanian ◽  
Hongyi Ma ◽  
Liqiang Wang ◽  
En-Jui Lee ◽  
Po Chen
Keyword(s):  
Seismic Source ◽  
3D Seismic ◽  
Source Inversion ◽  
Amazon Ec2

scholarly journals Fully probabilistic seismic source inversion – Part 1: Efficient parameterisation

2013 ◽  
Vol 5 (2) ◽  
pp. 1125-1162 ◽  
Author(s):  
S. C. Stähler ◽  
K. Sigloch
Keyword(s):  
Moment Tensor ◽  
Source Parameters ◽  
Practical Importance ◽  
Principal Component ◽  
Seismic Source ◽  
Empirical Orthogonal Functions ◽  
Time Function ◽  
Source Inversion ◽  
Source Time Function ◽  
Earthquake Parameters

Abstract. Seismic source inversion is a non-linear problem in seismology where not just the earthquake parameters themselves, but also estimates of their uncertainties are of great practical importance. Probabilistic source inversion (Bayesian inference) is very adapted to this challenge, provided that the parameter space can be chosen small enough to make Bayesian sampling computationally feasible. We propose a framework for PRobabilistic Inference of Source Mechanisms (PRISM) that parameterises and samples earthquake depth, moment tensor, and source time function efficiently by using information from previous non-Bayesian inversions. The source time function is expressed as a weighted sum of a small number of empirical orthogonal functions, which were derived from a catalogue of >1000 STFs by a principal component analysis. We use a likelihood model based on the cross-correlation misfit between observed and predicted waveforms. The resulting ensemble of solutions provides full uncertainty and covariance information for the source parameters, and permits to propagate these source uncertainties into travel time estimates used for seismic tomography. The computational effort is such that routine, global estimation of earthquake mechanisms and source time functions from teleseismic broadband waveforms is feasible.

scholarly journals Improved finite-source inversion through joint measurements of rotational and translational ground motions: A theoretical study

2016 ◽  
Author(s):  
Michael Reinwald ◽  
Moritz Bernauer ◽  
Heiner Igel ◽  
Stefanie Donner
Keyword(s):  
Inverse Problem ◽  
Ground Motions ◽  
Source Parameters ◽  
Normal Fault ◽  
Seismic Source ◽  
Vertical Gradient ◽  
Vertical Displacement ◽  
Source Inversion ◽  
Additional Information ◽  
Finite Source

Abstract. With the prospects of seismic equipment being able to measure rotational ground motions in a wide frequency and amplitude range in the near future we engage in the question how this type of ground motion observation can be used to solve the seismic inverse problem. In this paper, we focus on the question, whether finite source inversion can benefit from additional observations of rotational motion. Keeping the overall number of traces constant, we compare observations from a surface seismic network with 44 3-component translational sensors (classic seismometers) with those obtained with 22 6-component sensors (with additional 3-component rotational motions). Synthetic seismograms are calculated for known finite-source properties. The corresponding inverse problem is posed in a probabilistic way using the Shannon information content as measure how the observations constrain the seismic source properties. We minimize the influence of the source receiver geometry around the fault by statistically analyzing six-component (three velocity and three rotation rate) inversions with a random distribution of receivers. The results show that with the 6-C subnetworks the source properties are not only equally well recovered (even that would be benefitial because of the substantially reduced logistics installing half the sensors) but statistically some source properties are almost always better resolved. We assume that this can be attributed to the fact that the (in particular vertical) gradient information is contained in the additional motion components. We compare these effects for strike-slip and normal-faulting type sources and confirm that the increase in inversion quality for kinematic source parameters is even higher for the normal fault. This indicates that the inversion benefits from the additional information provided by the horizontal rotation rates, i.e. information about the vertical displacement gradient.

scholarly journals MARINE SEISMIC SURVEYS— A STUDY OF ENVIRONMENTAL IMPLICATIONS

2000 ◽  
Vol 40 (1) ◽  
pp. 692 ◽  
Author(s):  
R.D. McCauley ◽  
J. Fewtrell ◽  
A.J. Duncan ◽  
C. Jenner ◽  
M-N. Jenner ◽  
...  
Keyword(s):  
Sea Turtles ◽  
Seismic Source ◽  
Signal Propagation ◽  
Seismic Survey ◽  
Humpback Whales ◽  
Experimental Program ◽  
3D Seismic ◽  
Environmental Implications ◽  
Alarm Response ◽  
Air Gun

An experimental program was run by the Centre for Marine Science and Technology of Curtin University between March 1996 and October 1999 to study the environmental implications of offshore seismic survey noise. This work was initiated and sponsored by the Australian Petroleum Production and Exploration Association. The program:characterised air gun signal measurements; modelled air gun array sources and horizontal air gun signal propagation;developed an 'exposure model' to predict the scale of potential biological effects for a given seismic survey over its duration;made observations of humpback whales traversing a 3D seismic survey;carried out experiments of approaching humpback whales with a single operating air gun;carried out trials with an air gun approaching a cage containing sea turtles, fishes or squid; andmodelled the response of fish hearing systems to airgun signals.The generalised response of migrating humpback whales to a 3D seismic vessel was to take some avoidance manoeuvre at >4 km then to allow the seismic vessel to pass no closer than 3 km. Humpback pods containing cows which were involved in resting behaviour in key habitat types, as opposed to migrating animals, were more sensitive and showed an avoidance response estimated at 7−12 km from a large seismic source. Male humpbacks were attracted to a single operating air gun due to what was believed the similarity of an air gun signal and a whale breaching event (leaping clear of the water and slamming back in). Based on the response of captive animals to an approaching single air gun and scaling these results, indicated sea turtles displayed a general 'alarm' response at an estimated 2 km range from an operating seismic vessel and behaviour indicative of avoidance estimated at 1 km. Similar trials with captive fishes showed a generic fish 'alarm' response of swimming faster, swimming to the bottom, tightening school structure, or all three, at an estimated 2−5 km from a seismic source. Modelling the fish ear predicted that at ranges

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 Fully probabilistic seismic source inversion – Part 1: Efficient parameterisation

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 1055-1069 ◽  
Author(s):  
S. C. Stähler ◽  
K. Sigloch
Keyword(s):  
Moment Tensor ◽  
Source Parameters ◽  
Practical Importance ◽  
Principal Component ◽  
Seismic Source ◽  
Empirical Orthogonal Functions ◽  
Time Function ◽  
Source Inversion ◽  
Source Time Function ◽  
Earthquake Parameters

Abstract. Seismic source inversion is a non-linear problem in seismology where not just the earthquake parameters themselves but also estimates of their uncertainties are of great practical importance. Probabilistic source inversion (Bayesian inference) is very adapted to this challenge, provided that the parameter space can be chosen small enough to make Bayesian sampling computationally feasible. We propose a framework for PRobabilistic Inference of Seismic source Mechanisms (PRISM) that parameterises and samples earthquake depth, moment tensor, and source time function efficiently by using information from previous non-Bayesian inversions. The source time function is expressed as a weighted sum of a small number of empirical orthogonal functions, which were derived from a catalogue of >1000 source time functions (STFs) by a principal component analysis. We use a likelihood model based on the cross-correlation misfit between observed and predicted waveforms. The resulting ensemble of solutions provides full uncertainty and covariance information for the source parameters, and permits propagating these source uncertainties into travel time estimates used for seismic tomography. The computational effort is such that routine, global estimation of earthquake mechanisms and source time functions from teleseismic broadband waveforms is feasible.

scholarly journals Ambient Seismic Source Inversion in a Heterogeneous Earth: Theory and Application to the Earth's Hum

2017 ◽  
Vol 122 (11) ◽  
pp. 9184-9207 ◽  
Author(s):  
Laura Ermert ◽  
Korbinian Sager ◽  
Michael Afanasiev ◽  
Christian Boehm ◽  
Andreas Fichtner
Keyword(s):  
Seismic Source ◽  
Source Inversion

scholarly journals Introducing noisi: a Python tool for ambient noise cross-correlation modeling and noise source inversion

Solid Earth ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 1597-1615
Author(s):  
Laura Ermert ◽  
Jonas Igel ◽  
Korbinian Sager ◽  
Eléonore Stutzmann ◽  
Tarje Nissen-Meyer ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Noise Source ◽  
Seismic Source ◽  
Seismic Wave Propagation ◽  
Seismic Sources ◽  
Source Inversion ◽  
Cross Correlations ◽  
Forward And Inverse Modeling ◽  
Noise Cross Correlation ◽  
Spatially Varying

Abstract. We introduce the open-source tool noisi for the forward and inverse modeling of ambient seismic cross-correlations with spatially varying source spectra. It utilizes pre-computed databases of Green's functions to represent seismic wave propagation between ambient seismic sources and seismic receivers, which can be obtained from existing repositories or imported from the output of wave propagation solvers. The tool was built with the aim of studying ambient seismic sources while accounting for realistic wave propagation effects. Furthermore, it may be used to guide the interpretation of ambient seismic auto- and cross-correlations, which have become preeminent seismological observables, in light of nonuniform ambient seismic sources. Written in the Python language, it is accessible for both usage and further development and efficient enough to conduct ambient seismic source inversions for realistic scenarios. Here, we introduce the concept and implementation of the tool, compare its model output to cross-correlations computed with SPECFEM3D_globe, and demonstrate its capabilities on selected use cases: a comparison of observed cross-correlations of the Earth's hum to a forward model based on hum sources from oceanographic models and a synthetic noise source inversion using full waveforms and signal energy asymmetry.

Tsunami Simulation by Tuned Seismic Source Inversion for the Great 2011 Tohoku Earthquake

2017 ◽  
Vol 174 (8) ◽  
pp. 2891-2908 ◽  
Author(s):  
A. Petukhin ◽  
K. Yoshida ◽  
K. Miyakoshi ◽  
K. Irikura
Keyword(s):  
Tohoku Earthquake ◽  
Seismic Source ◽  
2011 Tohoku Earthquake ◽  
Source Inversion ◽  
Tsunami Simulation
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