article_snippet.sent: Geophysicists have long monitored how fast Earth's plates are moving, and We know that the entire subcontinent of India is being driven slowly but surely underneath Nepal and Tibet at a speed of around 1.8 inches per year.
article_snippet.sent: Over millions of years, the squeezing has crushed the Himalayas like a concertina, raising mountains to heights of several miles and triggering earthquakes on a regular basis from Pakistan to Burma.
article_snippet.sent: In the 81 years since Nepal earthquake, the land mass of India has been pushed about 12 feet into Nepal.
article_snippet.sent: Think of all that movement getting stored in a giant spring lying under Nepal.
article_snippet.sent: a giant spring lying under Nepal is stuck on a broad, rough surface which we call a fault plane (a fault line is what we see when a giant spring lying under Nepal emerges from the ground).
article_snippet.sent: Fallen: Nepal's historic landmarks .
article_snippet.sent: Sometimes, energy stored in a giant spring lying under Nepal gets big enough to slip catastrophically, releasing all that pent-up strain and generating shaking strong enough to destroy buildings and kill people over a huge area.
article_snippet.sent: Saturday's slip took place over an area about 1,000 to 2,000 square miles over a zone spanning the cities of Kathmandu and Pokhara in one direction, and almost the entire Himalaya mountain width in the other.
article_snippet.sent: A part of India slid about one to 10 feet northwards and underneath Nepal in a matter of seconds.