What are Earthquakes? The most dreadful and disastrous experience of nature is a catastrophic earthquake and it’s terrible after shocks. An earthquake is a sudden movement of the Earth, caused by the rough release of strain that has accumulated over time. According to the Geoscience of Australia, “Earthquakes are the vibrations caused by rocks breaking under stress. The underground surface along which the rock breaks and moves is called a fault plane.
Even though this powerful natural hazard can be disastrous or even catastrophic, you can learn more about them so that you’re more aware and prepared of what to do in case you are put into that situation. Lets start off with the consequences of an earthquake. The consequences depend on a combination of factors like the magnitude, depth, distance from a populated area, the nature of local earth materials, and also the way structures like houses, buildings, roads, railroads, utility lines, and pipelines are built. (Natural Hazards, Second Edition) Earthquake losses, like those of other disasters, tend to cause more financial losses in industrialized countries and more injuries and deaths in undeveloped countries. Earthquakes can also cause secondary disasters like tsunamis, a natural disaster where a series of waves of very great length and period, are usually caused by large earthquakes under or near oceans that are close to the edges of tectonic plates.
Earthquakes the Destructive Natural Phenomena An earthquake, one of the most destructive natural phenomena, consists of rapid vibrations of rock near the surface of the earth. It is the most terrifying of all natural phenomena and has brought fear since ancient times because of its sudden unpredictable occurrence and enormous capacity of destruction. A single shock usually last no more than a few seconds, although several quakes may last for as much as a couple of minutes. The quake as felt on the surface is always the result never the cause of some geologic process although the damage done may be immense. The Greek word for "shaking," and (when it applies to the earth) "earthquakes," is seismos.
The afore mentioned fault is called the San Andreas fault and is approximately 1300 kilometers long and a great source for Earthquakes and activity. San Andreas is unusual because unlike most faults, which are beneath the Earths surface, the San Andreas is visible on the surface. One of the bigger Earthquakes ever recorded ran along this fault and will be discussed later in the paper. The length and severity of an Earthquake does vary. Much in the way lightning is a preemptive sign that thunder will follow, foreshocks are a preemptive sign that a major Earthquake will follow.
The Physical and Human Factors Which Affect the Location and the Impact of the Earthquake Hazard Earthquakes are natural hazards that have occurred since the dawn of time. They are products of the Earth's ever-changing face and lead to the movement of the world's tectonic plates. An earthquake is a hazard resulting from major geological processes and the release of energy within the earth leading to catastrophic incidents such as earthquake and volcanic eruptions. The effects of earthquakes can have considerable damage to the physical and human environments and the impact and location of an earthquake can alter the damage of the process. Earthquakes are most likely to occur at the boundaries of the lithospheric plates.
This means that people in certain areas only have to prepare for those disasters that are likely to occur in their region. Throughout the world, natural hazards are a frequent occurrence. On a range of scales they create disaster, destruction and deaths of people. “A natural process only becomes a natural hazard when the risk of human loss is presented.” (Page 2) An earthquake is “a sudden shake of the Earth's crust caused by the tectonic plates colliding.” (Page 2) The vibrations may vary in magnitude. “The underground point of origin of the earthquake is called the focus.
EARTHQUAKES Objective: To define and discuss earthquakes and its effects. Earthquakes are a major catastrophe and can be a big threat to human lives. To understand earthquakes you must have a clear definition, know its mechanisms, be able to recognize the size and dynamics and understand its effects: I. Definition of Earthquake a. Earthquake b. Tsunamis c. Landslides d. Volcanoes II. Mechanism a. Faults b. Seismic Waves c. Aftershocks III.
1: Introduction Earthquakes are one of the most destructive natural disasters. They can cause many other natural disasters for example, tsunamis, avalanches or volcanic eruptions. Earthquakes occur when one tectonic plate collides with another. There are 15 main different tectonic plates spread around the globe. Earthquakes can be recorded with seismometers.
Understanding and Preparation of Earthquake An earthquake is a sudden movement of the Earth's lithosphere (its crust and upper mantle) by the release of build-up energy “in the form of low – frequency sound waves (seismic waves)” along geological faults or by volcanic activity. There are three types of the seismic wave: “primary (P) waves have a push – pull type of vibration, secondary (S) waves have a slide – to – slide types of vibration, and combination of primary (P) and secondary (S) of vibrations (HarperCollins Publishers, 2003). It can be measuring by the Richter scale. An earthquake is a natural geological phenomenon and more than 30,000 earthquakes that strong enough to felt by worldwide. It caused by the fast release of elastic energy stored in rock which been subject to great stress.
If these tectonic plates are moving at different rates relative to one another or are moving in different directions entirely, the rock at the boundaries will experience stress. Eventually the displacement between plates becomes large enough such that the rock under stress will rupture and release energy in the form of an earthquake. Interplate generated earthquakes account for the majority of naturally occurring earthquakes on earth. In less common instances, the stress regime created at plate boundaries can transfer to intraplate regions far away from plate boundaries. An inactive fault plane in such a region could be reactivated and rupture, generating an earthquake potentially far away from a plate boundary.