Why does the Earth tremble sometimes?
The moving tectonic plates, in which the uppermost layer of the Earth is divided, not only collide at many places but also often slide past each other. This causes friction leads to problems once in a while. Stress builds up, and which then gets discharged very quickly. There is a jerk-the Earth trembles This gives rise to shock waves that can cause a lot of damage at places, depending on the intensity of the earthquake and where they occur. Luckily, to some extent we can protect ourselves from these waves. A tsunami occurs if the centre of the earthquake lies below the sea.
How does a tsunami occur?
The Japanese word 'tsunami' means 'harbour wave. It is a series of water yvaves caused by the displacement of a large volume of a body of water, usually an ocean. though it can occur in large lakes. Tsunamis are caused by undersea landslides or by seaquakes, that is an earthquake whose epicentre lies below the ocean. If the seabed is displaced up to several metres, the water layer of several kilometres in thickness above it also moves with it. The wave caused by this movement has a lot of energy-much more than a wave of the same height whipped up by the wind. This becomes apparent when Fast, Wave becomes slower Hugo wave the wave moves towards the lower wave
and higher rolls over coast.
and higher rolls over coast.
What damages can earthquakes cause?
A weak earthquake-up to an intensity of 4.o on the Richter hardly causes move Earthquakes with stronger intensities can cause cracks in buildings. They lines get foundations of buildings, cause houses to collapse, and lead to landslides. a disrupted and gas leakage causes fires. In large earthquake catastrophes, bridges, dams, power plants get damaged-and often whole areas are devastated.
A weak earthquake-up to an intensity of 4.o on the Richter hardly causes move Earthquakes with stronger intensities can cause cracks in buildings. They lines get foundations of buildings, cause houses to collapse, and lead to landslides. a disrupted and gas leakage causes fires. In large earthquake catastrophes, bridges, dams, power plants get damaged-and often whole areas are devastated.
Where do earthquakes occur?
occur mainly at the borders of the plates where two plates slide past each other Most earthquakes occur in the Himalayan region. The on centre, the hypocentre: lies deep below the surface of the Earth. The point seismic the surface of the Earth lyiimmediately above this is calledthe epicentre' Scientists can I determine this point. They measure the time it takes the shock waves to reac the siesmic stations and draw circles around the epicentre and two other seismic stations. The radius of these circles corresponds to the measured time. The point of intersection is the epicentre Right below the epicentre, beneath the Earth's surface, lies the hypocentre.
occur mainly at the borders of the plates where two plates slide past each other Most earthquakes occur in the Himalayan region. The on centre, the hypocentre: lies deep below the surface of the Earth. The point seismic the surface of the Earth lyiimmediately above this is calledthe epicentre' Scientists can I determine this point. They measure the time it takes the shock waves to reac the siesmic stations and draw circles around the epicentre and two other seismic stations. The radius of these circles corresponds to the measured time. The point of intersection is the epicentre Right below the epicentre, beneath the Earth's surface, lies the hypocentre.
How do we save ourselves from earthquakes?
Living in an earthquake-prone zone is often unavoidable. For instance, almost entire Japan lies in an earthquake-prone zone. For this reason, buildings here are primarily made earthquake resistant' so that the loss can be minimized. Buildings are built on foundations made of steel balls or from elastic materials such as bamboo. In skyscrapers, a pendulum weighing several tons is installed in the upper floors, which minimizes the vibrations that start in the upper storeys when an earthquake occurs. If an earthquake occurs, we should take refuge, at best, in the open or seek protection under a table.
