Determination of Initial Sea Surface Displacement at Tsunami Source by a Part of Wave Profile

2018 ◽  
Author(s):  
Dmitry Kuzakov ◽  
Mikhail Lavrentiev ◽  
Andrey Marchuk
Keyword(s):  
Surface Displacement ◽  
Wave Profile ◽  
Sea Surface ◽  
Tsunami Source

scholarly journals Randomly distributed unit sources to enhance optimization in tsunami waveform inversion

2014 ◽  
Vol 2 (5) ◽  
pp. 3659-3682
Author(s):  
I. E. Mulia ◽  
T. Asano
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Surface Deformation ◽  
Waveform Inversion ◽  
Sea Surface ◽  
Tsunami Source ◽  
Unknown Parameters ◽  
Tsunami Waveform Inversion ◽  
Tsunami Waveform

Abstract. Determination of sea surface deformation generated by earthquakes is crucial to the success of tsunami modeling. Using waveforms recorded at measurement stations and assuming that the rupture velocity is much faster than the tsunami wave celerity, sea surface deformation caused by a tsunamigenic earthquake can be inferred through an inversion operation using the Green's function technique. However, this inversion method for tsunami waveforms possesses a limitation, in that the inverse matrix does not always exist because of the non-uniqueness of the solution. In addition to the large number of unknown parameters, which might produce many local optima on the misfit function measure, the search towards optimality is confined by the uniform distance of unit sources used in the regular Green's function. This study proposes a new method to both optimize the determination of the unknown parameters and introduce a global optimization method for tsunami waveform inversion. The method has been tested using an artificial tsunami source with real bathymetry data. A significant improvement is achieved by stochastically searching for an optimal distribution of unit source locations prior to the inversion.

Determination of Underwater Plate Dynamics Using Laser Beams

1974 ◽  
Vol 96 (3) ◽  
pp. 722-728
Author(s):  
Rudolph E. Croteau ◽  
Herman E. Sheets
Keyword(s):  
Near Field ◽  
Surface Displacement ◽  
Coupled System ◽  
Green Laser ◽  
Testing Facility ◽  
Acoustic Testing ◽  
Propeller Blades ◽  
The Relationship ◽  
Made In

Underwater plate vibration and its associated noise are of interest for the analysis of ship structures, propeller blades, and other areas of underwater acoustics. In order to analyze the relationship between a plate vibrating underwater and the acoustic pressure in the near-field, optical interferometric holography, using a blue-green laser beam, was used to determine surface displacement for the vibrating plate, which was excited through a fluid-coupled system. Acoustic measurements of the same source were made in a water tower concurrently with the holography and later at a precision acoustic testing facility. This method permits prediction of underwater plate modal frequencies and shapes with high accuracy.

Determination of initial tsunami wave shape at sea surface

2017 ◽  
Author(s):  
Mikhail M. Lavrentiev ◽  
Alexey A. Romanenko ◽  
Dmitry E. Kuzakov ◽  
Alexander P. Vazhenin
Keyword(s):  
Tsunami Wave ◽  
Sea Surface ◽  
Wave Shape

Towards Nonlinear Wave Reconstruction and Prediction From Synthetic Radar Images

2016 ◽  
Author(s):  
A. P. Wijaya
Keyword(s):  
Vertical Direction ◽  
Sea Surface ◽  
Sea State ◽  
Operational Effectiveness ◽  
State Reconstruction ◽  
Radar Images ◽  
First Results ◽  
Marine Radar ◽  
Offshore Activities

The use of remotely wave sensing by a marine radar is increasingly needed to provide wave information for the sake of safety and operational effectiveness in many offshore activities. Reconstruction of radar images needs to be carried out since radar images are a poor representation of the sea surface elevation: effects like shadowing and tilt determine the backscattered intensity of the images. In [1], the sea state reconstruction and wave propagation to the radar has been tackled successfully for synthetic radar images of linear seas, except for a scaling in the vertical direction. The determination of the significant wave height from the shadowed images only has been described in [2]. This paper will summarize these methods, and provides the first results for the extension to nonlinear seas.

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