Apart from the Indian subcontinent slipping under the Tibetan plateau at the rate of 21 mm every year, there are also five faults within the Kathmandu Valley capable of producing major earthquakes. The geological structure of Kathmandu makes it further vulnerable. Many observers have "linked the soil conditions of Kathmandu Valley to those of Mexico City which is notorious for its susceptibility to damage during and after earthquake. The lake bed structure of the Valley absorbs earthquakes and vibrates itself.