Hello my Steemian friends, on this occasion, I would like to share about Sumatra fault which is the main trigger of earthquake in Indonesia, especially on Sumatra island.
Source: earthobservatory.sg
The term Sumatra fault is widely known since the frequent occurrence of earthquakes on the island of Sumatra. The Sumatra fault has caused major earthquakes on Sumatra island such as the Liwa earthquake of 1932 and 1994, Kerinci quakes of 1909 and 1995 which caused considerable loss of life and material.
For the Aceh region, itself has frequent earthquakes due to the movement of Sumatra Fault, it's just not as big as the earthquake in Liwa and Kerinci. A rather large earthquake occurred on Tuesday, September 6, 2011, at 00.55 AM, measuring 6.7 on the Richter scale, and centered at 59 km northeast of Singkil Baru, Aceh Singkil Regency, at coordinates 2.81 North Latitude and 97.85 East Longitude.
In addition, the earthquake caused by the Sumatra Fault activity has also shaken on January 28, 2010. It was at 11:12 PM, magnitude 5.0 scale, centered 23 kilometers northwest Takengon at coordinates 4.82 North Latitude and 96.78 Longitude East.
After the earthquake in Takengon, proving that the threat of earthquake in Aceh not only from the earthquake centered on the sea, but the earthquake centers on land should also be aware of the segment of Sumatra Pattern.
Source: ibnurusydy.com
The Sumatra fault has several segments in Aceh that have been detected through geological map information mapped by Cameron and his friends. The map is published by the Center for Research and Development of Geology Department of Mines and Energy. The evidence of the existence of this fault is further reinforced by the appearance of the interpretation of aerial photographs as well as satellite images (remote sensing).
For the Aceh region, the Sumatra Fault is also called the Semangko Fault, divided into several segments: Lokop-Kutacane Fault, Blangkeujeren-Mamas Fault, Kla-Alas Fault, Reunget-Blankeujeren Fault, Anu-Batee Fault, Samalanga-Sipopoh Fault, Banda Aceh-Anu Fault, Lamteuba-Baro Fault.
The fracture stores a large amount of energy and when it is released one can cause earthquakes. When the release occurs suddenly and at the same time, this is very dangerous because it will cause a devastating earthquake. However, if the energy is released gradually, little by little, the earthquake generated is not too dangerous even sometimes not felt by humans unless only recorded by a seismograph tool.
Source: thinglink.com
Cesar ("Patahan" Indonesia language) is a geologic term meaning error. Why is this error called fault? It is said that when geologists tracked the distribution of minerals, such as coal, suddenly the layers disappeared and reappeared elsewhere in different ways. Finally, they concluded that the loss of the layer due to errors of earth structures that have moved or shifted. From here the term fault appears.
The existence of a fault does not always have negative connotations as the cause of earthquake disaster because in the earth the fracture is useful in the process of forming hydrocarbon traps (both petroleum and natural gas). Fracture structure is also very important as a way through magma, especially magma rich in precious minerals, which will form mineralization of precious metal minerals such as gold, silver, copper, iron, and so on. If so, we should not blame God for putting us on earth with many fractures.
To explain the fault with the lay language is difficult, but at least a fault occurs because of the shift of the earth layer from normal conditions. That is, the skin of the earth experiencing movement. There is a movement to stop altogether, this is called an inactive fault. The ongoing movement is called an active fault.
Source: australianscience.com
Sumatra Fault includes an active fault that has been moving since thousands of years ago when the formation of the Indonesian archipelago due to the collision of three large plates of the world that occurred about 45.6 million years ago. The collapsed plates are the Indian-Australian Ocean Plate moving relative to the north, the Eurasian Continental Plate moving south, and the Pacific Ocean Plate moving westward.
The pressure of the Indian-Australi Ocean Plate caused the position of Sumatra Island as it is today, displaced and rotated to form an angle with the equator. In fact, according to geologists, initially the island of Sumatra is the same position with the island of Java, ie parallel to the equator. However, its current position stretches from the northwest to the southeast and across the equator, as if dividing Sumatra island over two parts, northern part of Sumatra and southern hemisphere of the southern hemisphere. The existence of the plate collision also led to the emergence of hills which became known as Barisan hills (Bukit Barisan in Indonesia language) which position parallel with the fault.
That is why, along Barisan hills there is a valley that is straight and elongated. These valleys are the weak zone of Sumatra's great fault where the crust is cracked and one side with the other side moving horizontally. The movement pattern is generally to the right, ie the east block moves to the southeast and the western blocs instead. The weak zone ranges from the south to the valley of Semangko (Semangko Bay in Lampung), Kepahiang, Ketahun, Kerinci, Muara Labuh, Singkarak Maninjau, Rokan Kiri, Gadis, Angkola, Alas, Tangse and Lembah Aceh. This weak zone has the potential to trigger earthquake.
Source: rovicky.com
Why should a ground earthquake be wary? This earthquake did not trigger a tsunami, but because the earthquake center is generally very close to where human activity is, especially if the center of the earthquake is shallow, the vibration effect is very large: shake the earth layer strongly. The building will vibrate. If it lasts long, it is not impossible that various buildings will collapse, especially during this time many buildings are made to be ignored by the condition of earthquake vulnerability.
In the world there have been frequent devastating earthquakes, such as the earthquake in Thangsan, China, in 1976 which claimed 240,000 lives, an earthquake in Iran in 1990 that claimed 40,000 lives, and an earthquake in Armenia in 1998 which claimed 25,000 people.
For Indonesia, the potential earthquake faults include Sumatra/Semangko Fault, Palu-Koro Fault in Sulawesi, Cimandiri Fault, Lembang Fault in Java, and Sorong Fault in Papua.
Source :
- id.wikipedia.org
- Adriansyah, Faizal, 2012, Aceh Laboratorium Bencana, Banda Aceh.
My previous post about Geology:
- How long does the earthquake continue? Until the earth finds the position of stability. Then when will the earth be stable?
- A Scientific Explanation of How to Become a Society Who Understands the Earthquake
- Scientific Explanation About The Mystery of Earth's Layers
- Scientific Explanation About When Earth Shakes
- Scientific Explanation About The Land Keeps Moving
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