Indonesia earthquake kills over 260, why was it so deadly?
- November 24, 2022
- Posted by: OptimizeIAS Team
- Category: DPN Topics
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Indonesia earthquake kills over 260, why was it so deadly?
Subject: Geography
Context:
- A 5.6 magnitude earthquake with a depth of 10 kms (6.2 miles) left more than 260 dead and hundreds injured as buildings crumbled and terrified residents ran for their lives on Indonesia’s main island of Java.
Impacted area-
- The hardest-hit city is Cianjur, in the province of West Java and some 217 kilometres (135 miles) south of the capital, Jakarta.
Earthquake-
- An earthquake in simple words is the shaking of the earth. It is a natural event. It is caused due to release of energy, which generates waves that travel in all directions.
- The vibrations called seismic waves are generated from earthquakes that travel through the Earth and are recorded on instruments called seismographs.
- The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicentre.
Earthquakes based on the depth of focus
- The earthquakes are divided into three zones: shallow, intermediate, and deep based on their depth which ranges between 0 – 700 km.
- Shallow earthquakes have a focus of 0 – 70 km deep.
- Intermediate earthquakes have a focus 70 – 300 km deep.
- Deep earthquakes have a focus of 300 – 700 km deep.
Wadati–Benioff zone
- Deep earthquakes (300-700 km) are produced in this zone.
- It is a zone of subduction, along which earthquakes are common, which are produced by the interaction of a downgoing oceanic crustal plate against a continental plate.
- Some of the most powerful earthquakes occur along this zone.
- These earthquakes can be produced by slip along the subduction thrust fault or by slip-on faults within the downgoing plate as the plate is pulled into the mantle.
Damage caused by earthquakes depends upon-
- Magnitude and depth of the earthquake
- proximity to fault lines,
- Type of soil
- the shallowness of the quake and
- inadequate infrastructure that cannot withstand earthquakes.
Does Indonesia usually have earthquakes like this?
- Indonesia is frequently struck by earthquakes, volcanic eruptions and tsunamis because of its location on the arc of volcanoes and fault lines in the Pacific Basin known as the “Ring of Fire.”
- The area spans some 40,000 kilometres (25,000 miles) and is where a majority of the world’s earthquakes occur.
- Many of Indonesia’s earthquakes are minor and cause little to no damage.
- In February, a magnitude 6.2 earthquake occurred in West Sumatra province.
- In January 2021, a magnitude 6.2 earthquake caused havoc in West Sulawesi province.
- A powerful Indian Ocean quake and tsunami in 2004 killed 230,000 people in a dozen countries, most of them in Indonesia.
What is the Pacific Ring of Fire?
- The Ring of Fire, also referred to as the Circum-Pacific Belt, is a path along the Pacific Ocean characterized by active volcanoes and frequent earthquakes.
- It is largely a result of Plate Tectonics where the massive Pacific Plate interacts with less-dense plates surrounding it.
- The majority of Earth’s volcanic eruptions and earthquakes take place along the Ring of Fire.
- The next most seismically active region (5-6% of earthquakes) is the Alpide belt (which extends from the Mediterranean region, eastward through Turkey, Iran, and northern India.
Geographical Stretch of Ring of Fire
- The Ring of Fire is stretched to approximately 40,000 kilometres (24,900 miles) tracing boundaries between several tectonic plates including the Pacific, Juan de Fuca, Cocos, Indian-Australian, Nazca, North American, and Philippine Plates.
- The chain runs up along the western coast of South and North America crosses over the Aleutian Islands in Alaska and runs down the eastern coast of Asia past New Zealand and into the northern coast of Antarctica.
- Bolivia, Chile, Ecuador, Peru, Costa Rica, Guatemala, Mexico, United States, Canada, Russia, Japan, Philippines, Australia, Papua New Guinea, Indonesia, New Zealand, and Antarctica are some of the important places located in the ring of fire.