Reconstruction of Far-Field Tsunami Amplitude Distributions from Earthquake Sources

2016 ◽  
pp. 3703-3717
Author(s):  
Eric L. Geist ◽  
Tom Parsons
Keyword(s):  
Far Field ◽  
Earthquake Sources ◽  
Tsunami Amplitude

Reconstruction of Far-Field Tsunami Amplitude Distributions from Earthquake Sources

2016 ◽  
Vol 173 (12) ◽  
pp. 3703-3717 ◽  
Author(s):  
Eric L. Geist ◽  
Tom Parsons
Keyword(s):  
Far Field ◽  
Earthquake Sources ◽  
Tsunami Amplitude

scholarly journals Influence of Tsunami Aspect Ratio on Near and Far-Field Tsunami Amplitude

Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 178
Author(s):  
Natalia K. Sannikova ◽  
Harvey Segur ◽  
Diego Arcas
Keyword(s):  
Aspect Ratio ◽  
Near Field ◽  
Decay Rates ◽  
Far Field ◽  
Present Evidence ◽  
Positive Wave ◽  
Initial Wave ◽  
N Wave ◽  
Tsunami Amplitude ◽  
Wave Shapes

This study presents a numerical investigation of the source aspect ratio (AR) influence on tsunami decay characteristics with an emphasis in near and far-field differences for two initial wave shapes Pure Positive Wave and N-wave. It is shown that, when initial total energy for both tsunami types is kept the same, short-rupture tsunami with more concentrated energy are likely to be more destructive in the near-field, whereas long rupture tsunami are more dangerous in the far-field. The more elongated the source is, the stronger the directivity and the slower the amplitude decays in the intermediate- and far-fields. We present evidence of this behavior by comparing amplitude decay rates from idealized sources and showing their correlation with that observed in recent historical events of similar AR.

Attenuation Function Relationship for Far Field Earthquake Considered by Strike Slip Mechanism

2015 ◽  
Vol 754-755 ◽  
pp. 897-901
Author(s):  
Saffuan Wan Ahmad ◽  
Azlan Adnan ◽  
Rozaimi Mohd Noor ◽  
Khairunisa Muthusamy ◽  
Sk Muiz Sk Razak ◽  
...  
Keyword(s):  
Peak Ground Acceleration ◽  
Strike Slip ◽  
Far Field ◽  
Attenuation Relationship ◽  
Ground Acceleration ◽  
Slip Mechanism ◽  
Earthquake Sources ◽  
Peak Ground Accelerations ◽  
Function Relationship ◽  
The Relationship

An attenuation relationship for far field earthquakes considered by strike slip has been developed. The attenuation relationship function was develop using regression analysis. The database consisting of more than 130 peak ground accelerations from seven earthquake sources recorded by Seismology Station in Malaysia have been used to develop the relationship. This study aims to investigate the new relationship attenuation to gain exact peak ground acceleration at the location on site. Based on this study, the location is a structure located at Terengganu seaside.

Signature of coseismic off-fault damage in intermediate- and far-field radiation

2020 ◽  
Author(s):  
Kurama Okubo ◽  
Harsha S. Bhat ◽  
Esteban Rougier ◽  
Marine A. Denolle
Keyword(s):  
High Frequency ◽  
Near Field ◽  
Fault System ◽  
Far Field ◽  
Earthquake Rupture ◽  
Length Scales ◽  
Earthquake Sources ◽  
Planar Fault ◽  
Wide Range ◽  
Field Radiation

<p>Off-fault damage is observed around fault cores in a wide range of length scales, which is identified as an aggregation of localized fractures via geological and geodetic observations, or as low-velocity zone via seismological tomography. However, its seismological observables in earthquake traces, e.g. change in source spectra and/or radiation pattern, remains to be investigated. </p><p>Okubo et al. (2019) proposed an approach framework of physics-based dynamic earthquake rupture modeling with coseismic off-fault damage using the combined finite-discrete element method (FDEM). It shows a non-negligible contribution of coseismic damage to rupture dynamics, high-frequency radiation and overall energy budget, whereas the model domain is limited in the near-field region. This study efficiently computes intermediate- and far-field radiation propagating from earthquake sources with coseismic off-fault damage, and to identify its signature in the seismic traces.</p><p>We first conduct the dynamic earthquake rupture with coseismic damage and compute synthetic near-field radiation using FDEM-based software tool, HOSSedu, developed by Los Alamos National Laboratory. We then couple the output of HOSSedu to SPECFEM2D in order to compute intermediate- and far-field radiation. The HOSS-SPECFEM2D coupling can resolve complexities over wide range of length scales associated with earthquake sources with coseismic damage and wave propagation.</p><p>We conduct 2D dynamic earthquake rupture modeling with a finite planar fault as canonical simplest model. The comparison between the cases with and without allowing for coseismic off-fault damage shows differences in intermediate- and far-field radiation. 1) High-frequency components in ground motion are enhanced all around the fault. 2) The rupture arresting phase, which clearly appears at the stations located orthogonal to the fault for the case without off-fault damage, is damped due to the smoothed rupture arrest by coseismic damage around fault edges. 3) Radiated energy is enhanced in the direction parallel to the fault due to the substantial damage around fault edges.</p><p>These fundamental observables will help identify the existence of coseismic off-fault damage in real earthquakes. It would also contribute to resolve the mechanisms of earthquake sources and the potential distribution of aftershock locations. We also attempt to replace the planar fault to the real fault geometry, e.g. the fault system associated with the 2019 Ridgecrest earthquake sequence, and will investigate the signature of off-fault damage in the seismic traces recorded in intermediate- and far-field range.</p>

scholarly journals From earthquake size to far-field tsunami amplitude: development of a simple formula and application to DART buoy data

2013 ◽  
Vol 196 (1) ◽  
pp. 340-356 ◽  
Author(s):  
Emile A. Okal ◽  
Dominique Reymond ◽  
Hélène Hébert
Keyword(s):  
Simple Formula ◽  
Far Field ◽  
Earthquake Size ◽  
Buoy Data ◽  
Tsunami Amplitude ◽  
Dart Buoy

Possible applications of fraunhofer holography in high resolution electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 222-223 ◽  
Author(s):  
N. Bonnet ◽  
M. Troyon ◽  
P. Gallion
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Transfer Function ◽  
Radiation Damage ◽  
High Resolution Electron Microscopy ◽  
Far Field ◽  
Field Region ◽  
Crystalline Materials ◽  
Resolution Electron ◽  
The Ideal

Two main problems in high resolution electron microscopy are first, the existence of gaps in the transfer function, and then the difficulty to find complex amplitude of the diffracted wawe from registered intensity. The solution of this second problem is in most cases only intended by the realization of several micrographs in different conditions (defocusing distance, illuminating angle, complementary objective apertures…) which can lead to severe problems of contamination or radiation damage for certain specimens.Fraunhofer holography can in principle solve both problems stated above (1,2). The microscope objective is strongly defocused (far-field region) so that the two diffracted beams do not interfere. The ideal transfer function after reconstruction is then unity and the twin image do not overlap on the reconstructed one.We show some applications of the method and results of preliminary tests.Possible application to the study of cavitiesSmall voids (or gas-filled bubbles) created by irradiation in crystalline materials can be observed near the Scherzer focus, but it is then difficult to extract other informations than the approximated size.

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