Recent earthquake – Earthquakes are one of the most daunting natural disasters in the world. There are dozens or even hundreds of very strong earthquake and caused thousands and even millions of lives. Some earthquakes are recorded as the most powerful earthquakes including the earthquake that occurred on January 23, 1556 in Shensei, China. The quake claimed the lives of up to 830,000 people. The earthquake had a strength of up to 8 on the Richter scale.
Another earthquake also famous for the deadly was the earthquake that occurred in Syria on August 9 in 1138. The earthquake claimed the lives of up to 230,000 people. In our country, the most powerful earthquake occurred in 2004. Precisely on December 26 that occurred in Sumatra. The earthquake had a strength of about 9.1 on the Richter scale which caused the death of up to 227 898 inhabitants. The very strong earthquake comparable to the power of 1,000 atomic bombs.
Earthquakes in Indonesia is considered as the third largest earthquake in the world since 1900 in addition to the earthquake in Alaska and the earthquake in South Asia that led to the deaths of more than 300 thousand inhabitants.
The types of earthquakes
Earthquakes are usually classified into several categories based on: the depth, wave power, the epicenter, and based on the cause.
The first earthquake was an earthquake based on the depth. The earthquake is divided into three parts, namely, shallow earthquake, the earthquake and the earthquake in the middle. Shallow earthquakes typically occur at a depth of approximately 100 km from the earth’s surface. While the mid earthquake will occur at depths between 100 and 300 km below the earth’s surface. While the earthquake occurred at a depth of more than 300 km from the earth’s surface.
Another earthquake is an earthquake based on the cause. There are at least three types of earthquakes based on the causes of which are volcanic earthquakes are caused by the eruption of Mount Merapi or because of magma. The second was the earthquake due to debris or also known as the earthquake Terban. While the third is caused due to tectonic plate shifts.
Earthquake based epicenter is divided into two parts, namely a linear earthquake and earthquake Sentral.
Lastly, based on the strength of earthquake waves has three parts: the earthquake that caused by primary wave has a speed of between 7 Up to 14 km per second. And the second is due to the earthquake secondary waves that propagate at a speed of about 4 to 7 kilometers per second. Earthquake waves are categorized based on the strength of the latter is the result of long-wave earthquake have reached speeds of 3 to 4 kilometers per second.
The occurrence of earthquakes
The term “earthquake” refers to the ground vibrations caused by the energy released into the earth Due to the seismic waves. This can happen because in fact the earth beneath us is moving and shifting inside. Experts say that an earthquake usually begins as a result of the movement that occurs at the point of the Earth’s interior. If there is pressure and shifts, there are some parts of the layer in a very fragile earth will create a fault or a shift that we perceive as an earthquake. Most of the earthquakes caused by collisions between plates or fracture. An earthquake of this model is known as tectonic.
If the rocks that are in the earth’s crust under pressure due to the movement of plates on the continental shelf, the earthquake will occur. The slab slab is a slab that is in the ocean or a continent. In the process, when a slab of oceanic or continental plates on the scrape and collide with each other, it will result in a shock wave (earthquake).