Displaced Water Volume, Potential Energy of Initial Elevation, and Tsunami Intensity: Analysis of Recent Tsunami Events

Abstract. Sources of tsunamis are non-uniform and commonly uncorrelated and very difficult to predict. The best ideal way to appear their aspects is through heterogeneous or stochastic source models which are more realistic. The effect of random fluctuation of submarine earthquake modeled by vertical time-dependent displacement of a stochastic source model is investigated on the tsunami generation and propagation waves. The noise intensity parameter controls the increase of the stochastic bottom amplitude which results in increasing the oscillations and amplitude in the free surface elevation which provides an additional contribution to tsunami waves. The L2 norm of the free surface elevation, the displaced water volume and the potential energy are examined. These quantitative information about predicting tsunami risk are useful for risk managers who decide to issue warnings and evacuation orders. The horizontal average velocity flow rates of the tsunami wave are investigated. The average velocity flow rates can provide valuable information about the stochastic bottom topography by the distinctive velocity oscillations. Flow velocity is of importance in risk assessment and hazard mitigation which may provide a clear signal of tsunami flows. Time series of the flow velocities and wave gauges under the effect the water depth of the ocean are investigated.

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Theoretical Analysis of the Energy Required for Destratification of a Stratified Source Reservoir

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.295-298.1066 ◽

2013 ◽

Vol 295-298 ◽

pp. 1066-1069

Author(s):

Xin Sun ◽

Li Li Ye ◽

Ting Lin Huang

Keyword(s):

Potential Energy ◽

Water Temperature ◽

Minimum Energy ◽

Water Reservoir ◽

Total Potential Energy ◽

Water Levels ◽

Water Volume ◽

Source Water ◽

Average Water Temperature ◽

Total Potential

The minimum energy required for destratification of a source water reservoir is important to determine the design capacity of mixing system used to improve the source water quality. Taking Jinpen Reservoir in Xi’an, as a study case, the water volumes under different water levels of the reservoir were numerically calculated using the geometry data obtained with a RTK system. The total potential energy (PE) was determined by integrating the PE in each thin sub-layer over the water depth with density dependent on the water temperature. The average water temperature after complete mixing was calculated based on the heat exchange theory, and was consistent with the numerical result of temperature simulation. The difference of total potential energy before and after mixing was calculated for each month with the data of water temperature, water density and water volume. The minimum energy required for destratification increasing with the temperature gradient, was relatively high during the period from June to October, and reached a peak of 2412.92 kW·h in July.

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How the choice between nodal planes affects the estimate of tsunami hazard of an earthquake

10.5194/egusphere-egu2020-11048 ◽

2020 ◽

Author(s):

Anna Bolshakova ◽

Mikhail Nosov ◽

Sergey Kolesov ◽

Gulnaz Nurislamova ◽

Kirill Sementsov

Keyword(s):

Potential Energy ◽

Focal Mechanism ◽

Focal Depth ◽

Forecast Accuracy ◽

Basic Research ◽

Tsunami Hazard ◽

Tsunami Source ◽

Earthquake Focal Mechanism ◽

The Difference ◽

Initial Elevation

Usually tsunami warning is issued if a submarine earthquake is registered of magnitude exceeding a threshold, the value of which varies depending on the region where the earthquake took place and on the earthquake depth. Being simple and fast this approach is characterized by quite a low accuracy in the tsunami run-up heights estimate. The forecast accuracy can be improved if, instead of magnitude, we use the potential energy of the initial elevation in the tsunami source, calculated taking into account the earthquake focal mechanism. Automatic system for estimate of tsunami hazard using focal mechanism (Tsunami Observer, http://ocean.phys.msu.ru/projects/tsunami-observer/) was recently developed and implemented. Focal mechanisms derived from analysis of the recorded seismic waveforms has two possible solutions, i.e. two nodal planes. Short after an earthquake it is not possible to determine automatically which of the nodal planes is in fact the fault plane.The main purpose of this study is to reveal a difference in estimates of the potential energy of the initial elevation obtained making use of the first (NP1) and the second (NP2) nodal planes. All earthquake data including focal mechanism solutions were extracted from the Bulletin of the International Seismological Centre. Totally we processed nearly 6000 earthquakes Mw>6 occurred within the time period 1976 &#8211; 2019. All calculations were performed by means of the Tsunami Observer system. It was established that the potential energy calculated with use of NP1 (ENP1) and NP2 (ENP2) datasets can vary more than an order. However for overwhelming majority of seismic events (96.3%) the difference does not exceed two times, for significant number of events (74.1%) the difference does not exceed 1.2 times. In our presentation, we shall provide detailed description of calculation methods we use and the distribution of the ratio ENP1/ENP2. Also we shall discuss the influence of the focal depth and magnitude on the ratio ENP1/ENP2.AcknowledgementsThis work was supported by the Russian Foundation for Basic Research, projects 19-05-00351, 20-07-01098, 20-35-70038

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