Read some amazing facts about earthquakes
There are over a million quakes annually, including those too small to be felt. That works out to be about Approximately 80,000 per month, or approximately 2,600 per day, or approximately 2 per minute.india Updated: Mar 06, 2003 13:36 IST
There are over a million quakes annually, including those too small to be felt. That works out to be about Approximately 80,000 per month, or approximately 2,600 per day, or approximately 2 per minute.
The deepest boreholes have just penetrated to about 12 kilometres inside the Earth’s crust. Compare this manned voyages reaching moon, or unmanned ones on the verge of reaching beyond the extent of our solar system! As the Earth’s radius is about 6370 kilometres long, humans have penetrated less than one five hundredth of the distance to the centre of the planet.
The largest recorded earthquake in the world had a magnitude 9.5 in Chile on May 22, 1960.
Before electronics allowed recordings of large earthquakes, scientists built large spring-pendulum seismometers in an attempt to record the long-period motion produced by such quakes. The largest one weighed about 15 tons. There is a medium-sized one three stories high in Mexico City that is still in operation.
While parts of the continental crust are up to three and a half billion years old, no part of the oceanic crust, no sea floor is known to be older than around 200 million years old. Which means the ocean floor is being completely recycled.
In every 100 years India moves 200 cm north against the Asian plate, building up enormous pressure.
The average rate of movement in the San Andreas Fault Zone during the past 3 million years is 56 millimetres per year, about the same speed at which fingernails grow.
The East African Rift is a 50-60 kilometre wide area of active volcanoes and faulting that extends from north to south in eastern Africa for more than 3000 km. This massive rift system can be seen in parts of Mozambique, Malawi, Zambia, Tanzania, Uganda, Kenya, Ethiopia, Sudan, Eritrea and Somalia before it passes to Asia through the Red Sea, itself a part of this rift system.
The East African Rift system is at some point going to split the African landmass.
The first instrument to measure earthquakes was developed in 1751, referred to as the pendulum seismoscope.
Though pendulum seismoscopes were used to measure the shaking of the ground during an earthquake since 1751, and it wasn't until 1855 that faults were recognised as the source of earthquakes.
There are an estimated 500,000 detectable earthquakes in the world each year. 100,000 of those can be felt, and about a 100 of them cause damage.
Most earthquakes occur at depths of less than 80 km from the Earth's surface.
Though we can't be absolutely certain, the world's deadliest earthquake was probably the one in China in 1557, which killed an estimated 830,000 people, largely cave dwellers.
Quake beliefs. The Algonquin Indians of North America believe that the Earth lies on the back of a giant tortoise, and when it shuffles its feet the Earth quakes.