Geology on Pitara Kids Network

What Happens After an Earthquake?

Sat, 06 Apr 2002 21:55:39 +0000

People often wonder whether an earthquake can drastically change the topography of a region. A few tremors and some buildings that collapse does not mean that the shape of the earth has changed, does it? However, earthquakes can and do change the topography of the region.

An earthquake raised Rhodes island. The line of erosion (on the rock to the left) shows the sea level before the earthquake. The rise is uneven in different parts of the island, usually several meters. [Ввласенко / CC BY-SA]Ввласенко / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

Our earth is made of many layers just like an onion. We can divide it into four main layers: the inner or solid core, the outer or liquid core, mantle, and crust. The inner core is composed mostly of iron and is extremely hot. This heat causes the outer core to remain in a liquid or molten form.

Why is the Dead Sea dead?

Mon, 07 Mar 2005 13:54:44 +0000

The Dead Sea is indeed a very scary name for a lake. It is called so because nothing lives in it. There are no sea weeds or plants, no fish either. This is because the Dead Sea is nearly six times as salty as the ocean.

It also contains many other dissolved minerals, including magnesium chloride, calcium chloride and potassium chloride in large quantities. Whereas in fresh water, only minute quantities of these minerals are found. The high concentration of salt makes plant or animal life impossible.

What is a Volcano?

Wed, 24 Sep 2003 17:37:09 +0000

What is nature’s most powerful, most destructive, most dangerous form? Some would say an earthquake, others a cyclone. However, these phenomenon are relatively smaller and less destructive in scale compared to the fury of a volcano.

Fourteen miles southeast of Naples in Italy, lie the remains of an ancient town called Pompeii. The city flourished under the shadows of the towering Mount Vesuvius. In 79 AD, the volcano erupted, destroying the cities of Pompeii, Herculaneum, Stabiae and Torre Annunziata.

How are Earthquakes Recorded?

Wed, 13 Mar 2002 11:57:32 +0000

When an earthquake takes place, people say that it measured 6.2 or 6.5 on the scale. The scale they are referring to is the Richter Scale developed by Charles Richter in the 1930s.

The Richter Scale measures the magnitude of the seismic waves or vibrations that travels across the earth’s surface. The scale uses a logarithmic formula using high-frequency data collected from seismograph stations.

However, long before Richter developed his scale, a Chinese philosopher Chang Heng invented a device to measure earthquakes in 132 A.D. He constructed a large urn that had eight open-mouthed dragon-heads holding a ball each in their mouths, on the outside.

How do Earthquakes Happen?

Thu, 15 Aug 2002 04:16:22 +0000

Simply put, the shaking of the earth caused by a sudden shifting of rocks below its surface, is called an earthquake. The earths crust or outermost layer, is not made of one single piece of solid rock. It is actually made up of independent sheets of rocks called tectonic plates.

The tectonic plates of the world were mapped in the second half of the 20th century.

These plates slide against each other, giving rise to physical changes in the earths topography. The places where these tectonic plates meet each other, are called fault lines.

Why do Meteorites Strike the Earth?

Sat, 27 Apr 2002 10:32:14 +0000

On a hot summer afternoon, I sat down with my elder brother to play carom. I took the first strike and pocketed two coins. Then I did a little war dance. Wow!

Suddenly dada (Bengali for elder brother) had an idea. “How would it be if a fast-travelling object hit the earth? Quite like the way the striker hit the coins.”

I was amused. “How is it possible? The earth is so huge. Anyway there aren’t any strikers flying around in the solar system?”

Why do Earthquakes Occur?

Thu, 29 Jul 1999 07:19:27 +0000

As a result of upheavals below its surface, the earth shakes now and then. This shaking of the earth is known as an earthquake.

Few natural events are as violently destructive as an earthquake. It usually strikes without warning, giving off violent vibrations in the process. These vibrations not only shake the ground but also sometimes crack it open. And then, there is chaos, for earthquakes have been known to wipe out cities and civilisations.

What is an Earthquake?

Mon, 28 Oct 2002 22:15:31 +0000

One moment, the world seems just the way it was yesterday, the day before, last year, or even the day before the day before. All is well with the world. It’s a beautiful sunny day and you are sitting drinking your morning tea or coffee relaxed and enjoying the day. Suddenly there is a rattling of plates and glasses. Within seconds chairs and tables are rocking violently, the fans sway crazily and crockery is falling off the shelves. Help!! Sometimes plaster falls from the ceiling, walls develop cracks or worse still, they collapse. The very earth is shaking!

When the Earth Quakes

Sat, 01 Jun 2002 10:28:39 +0000

A host of questions on a natural disaster that makes the earth move with deadly results.

The Hot and Sizzling Volcano

Sun, 31 Jan 1999 04:43:51 +0000

Despite being the subject of considerable scientific study, Volcanoes continue to remain both dramatic and unpredictable. In 1991 Mount Pinatubo, 100 km north of the Philippines capital Manila, suddenly burst into life after lying dormant for more than six centuries. Most of the world’s active volcanoes occur in a belt around the Pacific Ocean, on the edge of the Pacific plate called the Ring of Fire. Indonesia has the greatest concentration with 90 volcanoes, 12 of which are active. The most famous, Krakatoa erupted in 1883 with such force that the resulting tidal wave killed 36,000 people and tremors were felt as far away as Australia.

Rocky Planet of Fire and Ice

Tue, 13 Mar 2001 01:36:33 +0000

Would you believe it? The soft sand that we sink into on the beach is actually rock? Sand is what a rock becomes after years of being worn down by rivers. Years of sea waves crashing against huge rocks and cliffs makes rocks break into small particles. And ultimately, they end up as sand. The colours of sands — yellow, red, grey, black — depend on the kind of rock it comes from. Sometimes desert sand is carried by winds across great distances, to seasides, increasing the amount of sand in the sea.

Earthshaking Terms

Fri, 21 Jul 2000 21:24:49 +0000

It’s a quiz about some of the terms that we hear and read about almost everywhere when an earthquake rocks the world.

The earth has more than 600 active volcanoes. Many of them are to be found ...

Mon, 15 Nov 2004 23:28:54 +0000

Minerals are graded according to their hardness, on a scale from 1 to 10. T...

Sun, 29 Aug 2004 18:53:43 +0000