A fault line may send out tiny shocks, called foreshocks, days or even weeks before a major earthquake. When a fault line is about to rupture and cause an earthquake, the types of waves it sends out change.Know More
Rupturing faults send out two different types of waves: P-waves and S-waves. The P-waves move faster, but the S-waves are the ones that cause the heavy damage -- along with the waves that move along the Earth's surface. Faults do not send out waves continuously, but once the rupture begins, earthquake sensors can pick up on incoming waves, and alert center staff have time to provide detailed warnings about the coming earthquakes.
The sensors are embedded in the ground, and when the P-waves hit, alert signals go to the center. While these systems provide only minutes or seconds of warning time, often that is enough to allow for the evacuation of major buildings if the quake is a major one. People living in earthquake-sensitive areas often have apps on their phones designed to receive these alerts, so they can prepare for the intensity of the earthquake at their location.
An earthquake early warning system called ShakeAlert was tested in California in January of 2012. ShakeAlert is able to transmit messages almost instantaneously, and may be able to save lives.Learn more about Earthquakes
An adequate earthquake survival kit includes a first aid kit, a home survival kit, a car survival kit and a work survival kit. The first aid kit and home survival kit should have enough supplies to last for three days.Full Answer >
Kashmir lies on top of the area where the Indian and Eurasian continental plates collide. Immense seismic stress builds up in this area and is released through earthquakes and other seismic activity. On October 8, 2005, this release of stress caused an earthquake that resulted in the death of more than 80,000 people, thousands of injuries and catastrophic property damage.Full Answer >
Earthquakes produce two types of potentially destructive waves that move through the earth from the point of the fault: primary, or pressure waves and secondary, or shear waves. Primary waves, also called P waves, exert a force of compression and travel through rock at speeds that can exceed 225 mph. Secondary waves, also called S waves, exert a shearing force and travel only half as fast as P waves, but are capable of causing much greater damage when they reach the surface.Full Answer >
Earthquakes happen when the boundaries of the Earth's tectonic plates bump and slide past one another; sometimes, they get stuck on jagged edges and cause earthquakes once they are released. These earthquakes are always followed by aftershocks starting from the same epicenter.Full Answer >