Tag: tides

The Ganga action plan was, launched by Shri Rajeev Gandhi, the Prime Minister on 14 Jan. 1986 with the main objective of pollution abatement, to improve the water quality by interception, diversion and treatment of domestic sewage and present toxic and industrial chemical wastes from identified grossly polluting units entering into the river.

A tidal bore, often simply given as bore in context, is a tidal phenomenon in which the leading edge of the incoming tide forms a wave (or waves) of water that travels up a river or narrow bay against the direction of the river or bay's current.

The spring tide occurs when the moon, the sun and the earth make in angle of $180^0$.

Neap tides are produced in the first and third quarters of the moon. Then the attractions of the Sun and the Moon are at right angles to each other.

• Tides are the rise and fall of sea level caused by the combined effects of gravitational forces exerted by sun, moon and earth.
  
• Tidal range is the vertical difference between high tide and its succeeding low tide.
  

During an earthquake, surface waves cause the most damage. Unlike other seismic waves that move deep inside the Earth, surface waves move along just under the surface of the Earth like waves in water. Surface waves are the slowest seismic waves and are the final waves to hit an area after an earthquake. 

First, P-waves move through compression through the deep layers of the Earth. P-waves are also carried by air and water, causing them to make a sound when they hit the Earth's surface. They result in minimal damage. The second group of waves is S-waves. They move up and down starting deeper in the Earth, and they cannot travel through air or water. Stronger S-waves do some damage when they reach the surface. Surface waves move in last. Their slow roll just under the surface provides the greatest risk for damage to man-made structures and changes to natural landforms.

When the moon is full or new, the gravitational pull of the moon and sun are combined. At these times, the high tides are very high and the low tides are very low. This is known as a spring high tide. Spring tides are especially strong tides (they do not have anything to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon.

When the moon is full or new, the gravitational pull of the moon and sun are combined. At these times, the high tides are very high and the low tides are very low. This is known as a spring high tide. Spring tides are especially strong tides (they do not have anything to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon.