Calculate tsunami velocity from water depth, depth from velocity, or estimated travel time from distance using depth or known speed.
Tsunami Velocity Formula
The long-wave approximation below estimates wave propagation speed when wavelength is much greater than water depth. This calculator uses g = 9.81 m/s².
- Where Vt is the tsunami velocity (MPH)
- g is the acceleration due to gravity (m/s^2)
- D is the depth of the water (m)
Take the square root of gravity times water depth to obtain m/s, then divide by 0.44704 to obtain mph. For travel time, this tool uses distance divided by a constant speed. It does not model a route across changing ocean depths; an arithmetic average depth is not generally equivalent.
What is a Tsunami Velocity?
Definition:
Tsunami velocity describes the rate of propagation of tsunami waves through the ocean based on the depth.
How to Calculate Tsunami Velocity?
Example Problem:
The following example outlines the steps and information needed to calculate Tsunami Velocity.
First, determine the depth of the water. In this example, the depth of the water is found to be 200 m.
Finally, calculate the Tsunami Velocity using the formula above:
Vt (mph) = SQRT(g*D) / 0.44704
Vt = SQRT(9.81*200) / 0.44704
Vt ≈ 99.0839 mph (44.2945 m/s).
FAQ
What factors can affect the velocity of a tsunami?
The velocity of a tsunami can be affected by several factors including the depth of the water, the topography of the ocean floor, and any geological obstacles it encounters. Changes in water depth as the tsunami approaches coastal areas can significantly alter its speed and energy.
Why is it important to calculate tsunami velocity?
Wave-speed models help explain tsunami propagation. This simplified calculator is educational and cannot issue warnings or predict a safe evacuation window. Follow official tsunami alerts and local emergency instructions. Operational forecasts use observations and detailed ocean-floor models.
Can tsunami velocity be used to predict the impact of a tsunami?
While tsunami velocity provides information on the speed of wave propagation, predicting the impact of a tsunami also requires understanding its amplitude, energy, and the coastal topography of the area it will hit. However, knowing the velocity can help in estimating the potential arrival times and preparing accordingly.
