Meaning of the period/ duration of occurrence, this duration is known as foreshocks and aftershocks respectively.
Magnitudes of occurrences, Earthquake can occur at the different moment magnitudes that are noticeable. Some can go unnoticed when the magnitude is minimal.
Its effects, Earthquakes have caused a greater lose to human kind. As it is continuing to posing inevitable hazards to the growing urban population, earthquake catastrophes are realistically avoidable and, ultimately, a superior solution can finish the hazards.
When and where the resent earthquake occurred, the most recent dangerous earthquake seriously affected some parts of the republic of Japan in the month of March 2011. It happened to be the Japanese massive earthquake since time immemorial.
Instruments used to measure earthquake, it is measured using observation from seismometer. The vibrations that lead to earthquake are described by peak acceleration and frequency.
Definition of Seismic waves, they are vast strains of energy emitted at times when an earthquake is travelling.
How it moves, the movements do occur in all directions within the earth crust.
Classification of Seismic waves, they are broadly categorized into two main branches, which are based on their movements.
The branches are body waves and surface waves. Surface waves generally travel close to the earth’s surface while the body waves are travelling deep in the earth crust. The difference between the two is that body waves have primary and secondary waves.
Composition of surface waves, they are made up of love waves and Rayleigh waves.
The different types of earthquakes for example naturally occurring, fault type, among others.
Earthquake should be handle technologically.
Naturally occurring earthquakes
Tectonic earthquakes are occurring anywhere on the earth. They do occur where there is enough kinetic elastic strain energy, which drives fracture transmission along a fault plane. It then forces the planes of a fault moving past each other efficiently and a seismically. These movements do occur only in the absent of irregularities or asperities alongside the fault facade that augment the frictional resistance.
The majority fault facades do encompass such asperities moreover this result into an appearance of stick-slip actions. Upon locking of the fault, continued relative movement between the plates results to rising stress and, therefore, Kinetic strain force in the capacity around the fault facade. This carries on until the moment when the stress has increased adequately to go through the roughness, all of a sudden permitting moving over the locked segment of the fault, discharging the kinetic energy. This power is discharged as a mixture of radiated flexible strain seismic waves, fault surface frictional heating, coupled with the disintegration of the rock, consequently resulting into an earthquake. When this process is combined with rare abrupt earthquake stoppage, is commonly known as the elastic-rebound theory.
Earthquake fault types
The geological researchers managed to identify three chief categories of fault that might cause earthquake. They are normal reverse and strike slip fault. Normal fault can occur in areas with extended crust for instance divergent boundary. Elastic energy released during fault raptures is stored in the tectonic plates. The available width is responsible for controlling maximum earthquake magnitude. Possibility of the most powerful earthquake is due to the plane’s width lying between 50 km to 100km in the brittle crust (Roz 147).
Earthquake a way from plate boundaries
Deformation extend over a much wider area compared to plated boundary, it is frequent in boundaries found in the continental lithosphere. Most earthquakes are occurring anti the plate boundary as in the situation of San Andreas Fault. They are alike to the strains formed in the border zone. Every tectonic plate contains internal stress area developing as a result of their contact with the adjacent plates. Moreover, the stress can also develop as a result of interaction between tectonic plates and sedimentary loading (Train 278). Generated stress can be enough to enhance letdown on the available fault planes, thus causing intraplate earthquake.
Shallow focus and deep-focus earthquakes
A greater number of tectonic earthquakes are originating from the fire’s ring in profundity not more than tens of kilometers. Shallow-focus earthquake occurs at depths smaller than 70km. Mid-focus earthquake or intermediate depth earthquakes. Earthquakes frequently take place in volcanic areas and are fuelled in those regions by magma movement in volcanoes. These types of earthquakes are serving like advance volcanic eruption warning. For instance, 1980 eruption of the Mount Saint Helens, (Train 346). Other than plate tectonic interactions, human activities can also cause earthquakes. Other terminologies used in earthquake study are aftershock, earthquake swarms, earthquake storms, and induced seimecity. In conclusion, earthquake has no benefits but cause several problems to people. Necessary plans like modern design and redesign of structures should be in place.
Earthquakes can be dangerous for survival of human beings. The following poem expresses the aftermath of an earthquake:
Greg, Roz. Earthquake: True Stories of Survival. New York. NY: The Rosen Publishing.
Group, 2007, Print.
Arthur, Train. The Earthquake. New York. NY: BiblioBazaar, 2009, Print.