What is a sinkhole?

Sinkholes are so wierd!

What is a sinkhole?

A sinkhole is a hole in the ground formed when the rock underneath dissolves by groundwater.

Where do they form?

Sinkholes usually form in areas of chalk or limestone - types of rock slowly that dissolve with rain water.

Sinkhole collapses are pretty common in the American state of Florida. Virtually the whole of the state is a limestone platform.

But sinkholes are extremely rare in the UK.

What are they like?

Sinkholes can be of all different sizes ranging from just a few metres to large ones around 20 metres deep.

Collapsed sinkholes generally have steep rock sides and may have streams that then flow underground.

From CBBC Newsround

Watch the following compilation!

Thousands of children are at risk after floods say charity

Thousands of children are at risk of disease after huge floods hit parts of northern India, according to Save the Children.

The charity are warning that thousands of people are still stranded in the mountains without access to clean water or medicines.

Ten days after the heavy rains first hit the state of Uttarakhand officials are worried that they are running out of time to get to survivors.

So far over 80,000 people have been rescued but bad weather and landslides are making it hard for the Indian army to get to everyone in need.

More than 600 people are now known to have died but officials fear the final number could be nearer to 1000.

Early monsoon rains in India this year are believed to be the heaviest in 80 years.

From CBBC News

Why do earthquakes happen?

Although the ground we walk on seems solid, the Earth's surface is actually made up of huge pieces of flat rock called tectonic plates.

They float on top of a layer of softer, squidgy rock called the mantle.

The plates move very slowly, over millions of years, and where they come together is called a fault.

When the plates rub together, the movement forces waves of energy to come to the Earth's surface.

This causes tremors and shakes - and these are called earthquakes.

They can cause huge amounts of damage, particularly in cities and built-up areas, where buildings, roads and bridges can collapse.

Why is it dangerous after an earthquake?

Earthquakes can cause a lot more damage after the first shock.

They are often followed by aftershocks, causing even more damage to already weakened buildings and roads.

Land, especially hills, can also be damaged by earthquakes and result in devastating landslides and mudslides.

What is an aftershock?

It's basically a smaller earthquake that happens after the main quake, in the same area.

If it's stronger than the first quake, it's renamed as the main earthquake and the original main quake becomes known as a foreshock.

Aftershocks can happen for up to two years after the original earthquake, losing power over time.

The risk of disease

In the chaos that can occur after an earthquake, sometimes electricity and fresh water can be lost. When there's no fresh water, this can lead to the spread of diseases.

Even getting hold of food and basic supplies can be difficult after an earthquake, because roads and other transport links can be destroyed.

The long-term effects of earthquakes can be felt for years afterwards.

From CBBC News

Cyclone leaves Mooloolaba covered in foam

This was the bizarre scene on Australia's Sunshine Coast over the weekend, where extreme weather has blanketed coastal towns with several feet of 'sea foam'.

Tourists, residents and emergency services were left bemused by the huge swathes of foam which were whipped up by high winds and then thrown onto land in eastern Australia.

Wild weather in the Australian state of Queensland has led to a small town becoming covered in foam whipped up by rough seas.

Residents and visitors could be seen playing in the foam and taking pictures of the unusual phenomenon in Mooloolaba on the Sunshine Coast.

Onlookers said the foam reached three metres high at its peak, with emergency services urging residents and tourists to cancel all non-essential travel.

From:

•  BBC News 
•  Yahoo! News

Eastern US gets back on its feet

Businesses and services in the north-eastern US are starting to reopen on Wednesday after two days of closure forced by storm Sandy.

Flights have resumed to airports in New York. Some federal offices, schools and Wall Street has reopened.

But many homes still have no power and the New York subway remains shut. More than 40 people are dead.

President Barack Obama, who has put campaigning on hold, is due to visit affected areas in New Jersey.

The cost of clearing up after the storm has been estimated at $30-40bn (£18-24bn).

New York Governor Andrew Cuomo said: "We have not seen damage like this in a generation."