Sumatera island (Bukit Barisan is one of Sumatra's fault lines). Image source wikipedia
In 2004 Aceh, located on the island of Sumatra suffered a devastating earthquake, the earthquake also triggered a tsunami that made hundreds of thousands of people killed, actually, there is one important lesson that we get from a disaster that is one of the areas prone to an earthquake is Sumatra island.
As we know that the earthquake is a land that shakes due to the movement of the earth's plate or can also be triggered by the eruption of the mountain, the data says that the western part of Sumatra island is the most vulnerable areas[source].
This is because a western part of an island of Sumatra near the collision of two plates of earth, namely the Indian ocean plate and the Sumatra plate, Indian Ocean Plate moves pressed down plates of an island of Sumatra.
At this stage the Mentawai islands and Nias are generally attached with rocks above it and as we know that, the pressure of the Indian Ocean plate will continue to press the undersides of the islands.
Well, I will give a simple example. TThe pressure imposed by the Indian Ocean plate on the Mentawai Islands and Nias can be likened to a large spring that continues to be pressed to the limit, if a spring bearing can no longer hold the press load then a cushion will be loose and bounce off, as well as the Mentawai and Nias Islands, the Mentawai and Nias islands will be bounced when the pressure of the Indian Ocean plate is no longer able to be retained by the retaining rocks of the island.
The Indian Ocean Plate presses the Sumatran islands off the south side and causes Sumatra to move slightly northward, as well as the southern side going opposite. The problem is that the northward impulse cannot be neutralized by subduction zones (large fault) and Mentawai island.
Every day the pressure received by the Sumatran plate grew until the stones that attached to the east and west of this fault line could no longer hold it until a tremendous earthquake to neutralize the pressure occurred suddenly. The western part of the Earth moves suddenly toward the north and the east moves towards the south.
The above explanation is the answer to why Sumatra is often an earthquake.
What happens during an earthquake in Sumatra?
The ground around the fault will move in the opposite direction and cause a crack of ground with a width of one to several meters.
Shocks will occur for several minutes.
There will be aftershocks on a smaller scale, up to a few days or weeks with increasing frequency until there are no more aftershocks.
Generally, large earthquakes will cause extraordinary damage.
Tectonic earthquakes usually can trigger more active volcanic activity and cause volcanic earthquakes.
One of the known fractures in Sumatra is the Semangko fault (the great fault of Sumatra), this fault formed in the millions of years ago when the Indian Ocean Plate crashed slightly on the west side of Sumatra. The major fractures of Sumatra stretch from Aceh to Lampung.
Ngarai Sianok (Sumatra fault). Image source wikipedia
Sumatra's major fault is a shear fracture and can easily be seen in Bukitinggi precisely Ngarai Sianok.
In other words, a fracture is an earthquake path that should be avoided, so what should we do to avoid an earthquake?
- We are only able to anticipate the earthquake.
- Know and learn the lane of an earthquake in your area.
- If it turns out that you are close to the earthquake lane then you should build a house that is resistant to earthquakes, such as wooden houses.
- Do not build houses and public facilities too close (around 5 KM) with earthquake lane.
- Arrange your furniture well, so at the time of the earthquake, the furniture and items that are in your home cannot be harmful, such as falling and so forth.
Can we know when will the earthquake again?
Keep in mind, earthquake is a natural process that repeats so that if there is an area that has experienced an earthquake then it is certainly in the future will experience an earthquake again, now scientists and engineers can predict earthquakes that have and will occur in certain areas can also estimate when the earthquake time.
The estimates of these experts are actually based on repeated earthquake processes and several other aspects.
Why should we know this?
As a Sumatran islander I should share this information with you and as an Engineer then I feel it is worthy to be known by other engineers especially the construction field, so with this information we can anticipate the worst thing we do not want in the future.
This is the only thing I can write on this occasion, over all the mistakes and lack of unintentional writing as a servant of God, I apologize.
Thanks to friends who have visited this blog and provided constructive comments, as well as scientists who are willing to sacrifice their time for a better civilization.
BEST REGARDS @kharrazi