scholarly journals Comparison of Earthquake Source Models for the 2011 Tohoku Event Using Tsunami Simulations and Near-Field Observations

2013 ◽  
Vol 103 (2B) ◽  
pp. 1256-1274 ◽  
Author(s):  
B. T. MacInnes ◽  
A. R. Gusman ◽  
R. J. LeVeque ◽  
Y. Tanioka
Keyword(s):  
Near Field ◽  
Earthquake Source ◽  
Field Observations ◽  
Source Models

Seismological Constraints on Fault-Slip Source Models and Rupture Characteristics of Global Large Earthquakes (Mw ≥ 7.5) and Associated Tsunamis

2020 ◽  
Author(s):  
Seda Yolsal-Çevikbilen ◽  
Tuncay Taymaz
Keyword(s):  
Near Field ◽  
Fault Slip ◽  
Earthquake Source ◽  
P Wave ◽  
Slip Distribution ◽  
Distribution Models ◽  
Tsunami Waves ◽  
Source Mechanisms ◽  
Source Models ◽  
Large Earthquakes

<p>Large and destructive earthquakes (M<sub>w</sub>≥ 7.5) occur worldwide particularly along the major subduction zones causing extensive damage and loss of life in the hinterland of epicentral region. Source models and rupture characteristics of these earthquakes (i.e. faulting geometry, focal depth, non-uniform finite-fault slip distributions) can be precisely determined by using seismological data and multidisciplinary earth-science observations. It is also known that earthquake source parameters play key roles in the modelling of secondary events such as earthquake-induced tsunamis. There are many studies emphasizing the importance of using heterogonous slip distribution models of earthquakes in mathematical tsunami simulations to predict synthetic tsunami waves more consistent with the observed ones. In this study, we obtained double-couple source mechanisms and slip distribution models of complex large earthquakes (M<sub>w</sub>≥ 7.5) lately occurred at different parts of the Earth. For this purpose, we used point-source teleseismic P- and SH- body waveform inversion and kinematic slip distribution inversion techniques. Besides, azimuthal distributions of P- wave first motion polarities, which are recorded by near-field and regional seismic stations, are checked to approve obtained minimum misfit source mechanism parameters of earthquakes. We essentially observed that tsunamigenic earthquakes occurred at shallow focal depths (h ≤ 70 km) with dip-slip source mechanisms and rather complex slip distributions along the fault planes. However, in some cases, tsunami waves may be unexpectedly triggered due to the secondary effects of large strike-slip earthquakes (e.g., September 28, 2018 Palu, Indonesia - M<sub>w</sub>7.5). Here, we discuss our inversion results, which reveal the significant contributions of earthquake source studies on resolving the relationships between the faulting geometry, rupture characteristics and tsunami generation. Furthermore, the necessity of high-resolution bathymetry data in numerical tsunami simulations is highlighted for the modelling of tsunami waves, in particular, recorded at the near-field tide-gauge stations. This study is partially supported by the Turkish Academy of Sciences (TÜBA) through GEBIP program.</p>

scholarly journals Near-field observations of light confinement in a two dimensional lithium niobate photonic crystal cavity

2011 ◽  
Vol 110 (7) ◽  
pp. 074318 ◽  
Author(s):  
Jean Dahdah ◽  
Maria Pilar-Bernal ◽  
Nadège Courjal ◽  
Gwenn Ulliac ◽  
Fadi Baida
Keyword(s):  
Photonic Crystal ◽  
Lithium Niobate ◽  
Near Field ◽  
Field Observations ◽  
Two Dimensional ◽  
Photonic Crystal Cavity ◽  
Light Confinement

scholarly journals Source modeling and inversion with near real-time GPS: a GITEWS perspective for Indonesia

2010 ◽  
Vol 10 (7) ◽  
pp. 1617-1627 ◽  
Author(s):  
A. Y. Babeyko ◽  
A. Hoechner ◽  
S. V. Sobolev
Keyword(s):  
Real Time ◽  
Scaling Laws ◽  
Near Field ◽  
Warning System ◽  
Source Characterization ◽  
Source Modeling ◽  
Plate Interface ◽  
Tsunami Warning System ◽  
Tsunami Early Warning ◽  
Source Models

Abstract. We present the GITEWS approach to source modeling for the tsunami early warning in Indonesia. Near-field tsunami implies special requirements to both warning time and details of source characterization. To meet these requirements, we employ geophysical and geological information to predefine a maximum number of rupture parameters. We discretize the tsunamigenic Sunda plate interface into an ordered grid of patches (150×25) and employ the concept of Green's functions for forward and inverse rupture modeling. Rupture Generator, a forward modeling tool, additionally employs different scaling laws and slip shape functions to construct physically reasonable source models using basic seismic information only (magnitude and epicenter location). GITEWS runs a library of semi- and fully-synthetic scenarios to be extensively employed by system testing as well as by warning center personnel teaching and training. Near real-time GPS observations are a very valuable complement to the local tsunami warning system. Their inversion provides quick (within a few minutes on an event) estimation of the earthquake magnitude, rupture position and, in case of sufficient station coverage, details of slip distribution.

Average Q and yield estimates from the Pahute Mesa test site

1987 ◽  
Vol 77 (4) ◽  
pp. 1274-1294
Author(s):  
R. W. Burger ◽  
T. Lay ◽  
L. J. Burdick
Keyword(s):  
Time Domain ◽  
Near Field ◽  
Energy Levels ◽  
Source Model ◽  
Spectral Shape ◽  
Field Amplitude ◽  
Far Field ◽  
Source Models ◽  
Attenuation Models ◽  
Shape Data

Abstract Attenuation models, with and without frequency dependence, have been developed through analysis of time-domain amplitude measurements and teleseismic spectral shape data from Pahute Mesa nuclear explosions. The time-domain analysis is based on a near-field to far-field amplitude comparison. The near-field amplitude information is incorporated in two parameterized explosion source models (Mueller-Murphy and Helmberger-Hadley) based on analyses of near-field data. The teleseismic amplitude observations are from a large data set of WWSSN short-period analog recordings. For the narrow-band time-domain data, the various source and attenuation models are indistinguishable. We utilize the spectral shape data in the 0.5- to 4-Hz band as a constraint on the source-attenuation models at higher frequencies, concluding that either source model, when convolved with the appropriate frequency-dependent Q model, can be consistent with both the near-field and far-field time-domain amplitudes and the spectral shape data. Given the trade-off between source and attenuation models and the similarity of the different source models in the 0.5- to 4-Hz band, it is difficult to prefer clearly one source model over the other. The Mueller-Murphy model is more consistent with surface wave amplitude measurements because of larger predicted long-period energy levels. Whether or not frequency dependence is included in the attenuation model, the value of t* near 1 Hz is about 1.0 sec (assuming the Mueller-Murphy source model) or 0.8 sec (assuming the Helmberger-Hadley source model). This 0.2 sec difference results from greater 1-Hz energy levels for the Mueller-Murphy source model. Adopting an average attenuation model, predicted amplitudes and yields are shown to be within the uncertainty of the data for all the events analyzed.

Nonlinear distortion of signals radiated by vibroseis sources

Geophysics ◽  
2004 ◽  
Vol 69 (4) ◽  
pp. 968-977 ◽  
Author(s):  
Andrey V. Lebedev ◽  
Igor A. Beresnev
Keyword(s):  
Thin Layer ◽  
Nonlinear Response ◽  
Nonlinear Distortion ◽  
Near Field ◽  
Quantitative Description ◽  
Harmonic Distortion ◽  
Seismic Energy ◽  
Field Observations ◽  
Contact Nonlinearity ◽  
The Difference

A model of nonlinearity of the contact between the vibrator baseplate and the ground is proposed to describe the distortion of vibroseis signals in the near‐field. A thin layer between the baseplate and the soil exhibits a strong nonlinear response because of the difference in its rigidity between the compression and tension phases. The model allows for a quantitative description of the transmission of seismic energy into the ground, including the observed harmonic distortion. However, the contact nonlinearity does not lead to the dependence of wave traveltimes on the amplitude of the force applied to the ground. This fact can be used in field observations to localize the source of the observed harmonic distortion.

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