A: Earthquakes are very useful to humans because they provide a picture of what’s going on underground. Earthquakes can also tell us about the internal structure of the Earth. By measuring the time it takes the seismic waves to travel through the Earth we can map out the structure of the Earth down to the core.

Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little.

Earthquakes are caused due to sudden lateral or vertical movements in the crust of the Earth. Or we can say that when tectonic plates ride over the other and cause the collision of orogeny or mountain building. The largest faults are formed on the surface of the Earth due to boundaries between moving plates.

Earthquakes usually cause severe damage to urban centres, resulting in the loss of life and damage to homes and other infrastructure. Although risks are normally associated with cities, the effects on the rural sector and farming communities can be devastating.

Earthquakes often cause dramatic changes at Earth’s surface. In addition to the ground movements, other surface effects include changes in the flow of groundwater, landslides, and mudflows. Earthquakes can do significant damage to buildings, bridges, pipelines, railways, embankments, dams, and other structures.

Earthquakes can be very dangerous, if you are in the wrong place. They can make buildings fall down and set off landslides, as well as having many other deadly effects. An earthquake that occurs at the bottom of the sea can push water upwards and create massive waves called tsunamis.

The Philippines belong to the Pacific Ring of Fire where the oceanic Philippine plate and several smaller micro-plates are subducting along the Philippine Trench to the E, and the Luzon, Sulu and several other small Trenches to the W.

The Pacific Ring of Fire stretches across 15 more countries including Indonesia, New Zealand, Papa New Guinea, Philippines, Japan, United States, Chile, Canada, Guatemala, Russia and Peru etc (fig. 3).

One such area is the circum-Pacific Ring of Fire, where the Pacific Plate meets many surrounding tectonic plates. The Ring of Fire is the most seismically and volcanically active zone in the world.

Kilauea volcano

1,500 volcanoes