Causes are a major topic in the discipline. At present, there are theories of continental drift and seafloor expansion, and the more popular theory is the theory of plate tectonics, which is generally accepted. The junction of plates and plates is a zone where crustal activity is more active, and it is also a zone where volcanoes and plates are more concentrated. The plate theory is the synthesis and extension of continental drift, sea bottom expansion and other theories, although it can not solve all the problems of crustal movement, but it points out the direction for the theoretical study of the cause.
What is the epicenter and epicenter
The place where the ** occurs underground is called the "epicenter", and the ground directly opposite the epicenter is called the "epicenter". The area near the epicenter where the vibration is greatest and generally the most devastation is also known as the "extreme earthquake zone". The vertical distance from the epicenter to the hypocenter is called the "hypocenter depth". The world's above ** are shallow sources**.
Is magnitude and intensity the same thing?
Magnitude is a measure of energy according to a certain microscopic standard. It is calculated based on the records of the ** instrument and is only related to the ** energy. Intensity refers to the actual impact of the ground on the ground, that is, the intensity of the ground movement or the degree of ground damage, the intensity is not only related to the magnitude of the earthquake itself, but also related to the depth of the epicenter, the distance from the epicenter and the conditions of the medium through which the wave passes.
*What are the direct disasters and secondary disasters?
A strong ** can cause a variety of disasters, which are generally divided into direct disasters and secondary disasters. Direct disasters refer to the direct disaster losses caused by the occurrence of the first disaster, such as the collapse of various buildings such as houses, bridges, dams, people, livestock, property losses, and production interruptions, and this kind of loss is particularly prominent in large cities, large industrial and mining and other densely populated and densely populated areas. Secondary disasters refer to floods caused by river overflow and dam collapse caused by major earthquakes, ignition, explosion and pollution caused by damage to equipment such as flammables, explosives and highly toxic substances, and indirect losses caused by bacterial transmission, water pollution and plague.
*What are the precursors.
Before, the abnormal phenomena related to ** that occur in nature are called **precursors, including two categories: microscopic precursors and macroscopic precursors. Common precursor phenomena include abnormal activity, wave velocity change, crustal deformation, groundwater anomaly change, groundwater chemical composition change, in-situ stress change, geoelectric change, geomagnetic change, gravity anomaly, animal geoacoustic anomaly, etc. Of course, the above anomalous changes are very complex, and often not necessarily caused by **. For example, the rise and fall of the water table is related to rainfall, early dryness, artificial pumping and irrigation.