4MEDIA REPORT ON EARTHQUAKES
Media report on earthquakes
When the earth fault suddenly slips, the ground shakes from the seismic energy emanating from the slip (Australian Government, n.d.1). Seismic energy can be termed as the force generated when the earth shakes and vibrates (Kusky, 2008). The shaking of the ground, which sometimes leads to the demolition of property, is what is typically termed as the earthquake.
An earth slip is the comparative disarticulation of previously adjacent spots on differing sides of a given fault (Anderson, 2011). When crust blocks move or slide against each other, a fracture may be forced, and this fracture is what is termed as the fault. The crust, according to Anderson (2011) is the earth’s furthest major layer, whose thickness ranges from about 10 to 65 kilometers. However, it is also worth noting that the topmost layer of the crust, which ranges from 15 to 35 kilometers, is fragile enough to generate earthquakes.
On earth’s outer surface, there are thick, large and thin plates moving comparative to one another, known as the tectonic plates (USGS, 2016b). It emerges that friction can cause the edges of the tectonic plates to stick thus releasing stress. When this stress overcomes the resistance, an energy wave is released from the point of contact, and this energy moves through the crust of the earth causing the vibrations and shaking felt like the earthquake.
Different regions have different plates, whose sticking together can lead to earthquakes (Australian Government, n.d.2). For example, the North American Plate and the Pacific Plate can be found in California in the USA (USGS, 2016). The North American Plate majorly consists of the North American Continent and segments of the Atlantic Ocean floor. On the other hand, the Pacific Plate comprises of the California Coastline and the Pacific Ocean floor (USGS, 2016).
Interestingly, Australia is not near the great tectonic plates that are responsible for the several earthquakes, yet it sometimes experiences earthquakes (Johnson, 2009). In 2012, for example, Australia experienced an earthquake that measured 5.2 on the Richter scale. The quake’s magnitude or size is determined by the seismic wave amplitude measurement as registered on the seismograph and also the distance between the earthquake and the seismograph.
The shaking extensity of a given earthquake greatly depends on factors such as topography, epicenter distance, magnitude, and the conditions of the local ground. The Modified Mercalli (MM) intensity scale is used to rate earthquake effects, and it ranges from I to XII (where I is the imperceptible and XII total destruction) (Australian Government, n.d.1).
Although Australia does not sit at the tectonic plate edges, its proximity to the Indo-Australian plate makes it vulnerable to earthquakes (ABC Science, 2012). However, it is the southern part of Australia that receives the most earthquakes based on its proximity to the plate. When tensions and stresses occur on the Indian plate, the energy wave is sufficient enough to reach the southern part of Australia, where it erupts like an earthquake (Stein & Mazzotti, 2007). Earthquakes in Australia with magnitudes below 3.5 rarely cause harm. However, it is important for people to be aware of their environment and understand that being far from the tectonic plates does not mean that the region is immune to earthquakes. The seismic waves can still travel thousands of kilometers underground and unleash terror in areas far away from the source of the tremor.
ABC Science. (2012). What caused the recent earthquakes in Australia? Retrieved from http://www.abc.net.au/science/articles/2012/05/01/3492944.htm
Anderson, M. (2011). Investigating plate tectonics, earthquakes, and volcanoes. New York, NY: Britannica Educational Publishing.
Australian Government. (n.d.1). What is an earthquake? Retrieved from http://www.ga.gov.au/scientific-topics/hazards/earthquake/basics/what
Australian Government. (n.d.2). Where do earthquakes occur? Retrieved from http://www.ga.gov.au/scientific-topics/hazards/earthquake/basics/where
Johnson, D. (2009). The geology of Australia (2nd ed.). Cambridge, UK: Cambridge University Press.
Kusky, T. (2008). Earthquakes: Plate tectonics and earthquake hazards. New York, NY: Infobase Publishing.
Stein, S., & Mazzotti, S. (2007). Continental intraplate earthquakes: Science, hazard, and policy issues. Boulder, CO: Geological Society of America.
USGS. (2016). What is an earthquake and what causes them to happen? Retrieved from https://www2.usgs.gov/faq/categories/9827/3343
USGS. (2016b). Earthquake glossary—tectonic plates. Retrieved from http://earthquake.usgs.gov/learn/glossary/?term=tectonic%20plates