Thread:Comments:7.7 magnitude earthquake hits Nicobar Islands, India/ Volcanoes result in earthquakes

Why did the island of Java alone experience earthquake on 2009-09-02 ?

On 2009-09-02 the earthquake which was of 7.3 on the Richter scale and shook Java,

one of the islands in the group of Indonesian islands, claimed 75 lives.

The explanation given by geologists is that, India and Australia are found on a huge rocky plate, which is moving in the northern direction and sliding below the rocky plate on which the group of Indonesian islands is situated and rubbing against it. This is the root cause of earthquakes.

But why did the island of Java alone experience earthquake on 2009-09-02 ?

Why didn’t the island of Sumatra or the island of Andaman experience earthquake on 2009-09-02 ?

How is it possible for the Indo-Australian rocky plate to slide only below the island of Java alone?

How is it possible for the Indo-Australian rocky plate to slide below different islands on different days? What is the real reason behind the striking of earthquakes in different islands of the Indonesian islands on different days?

Volcanoes result in earthquakes. There are one hundred and thirty volcanoes in the Indonesian islands. When the molten rock material in these volcanoes cools down and hardens to form rocks, hot gases and water are released from it. This produces rocks of lesser density from high density molten rock. A thing of lesser density will float in a liquid of higher density.

Hence, when the newly formed rocks of lesser density in the volcanoes below the Indonesian islands rise upwards their edges rub against the edges of the nearby rocky plates, resulting in earthquakes on that particular island alone.