Indonesia Earthquake

Syllabus: General Studies Paper 1

The death toll from a 5.6-magnitude earthquake in Indonesia has risen to 162 with hundreds injured and over 13,000 displaced.

About the disaster

• The US Geological Survey said the magnitude 5.6 quake was centered in the Cianjur region in West Java province at a depth of 10 kilometres (6.2 miles).
• Indonesia’s Meteorology, Climatology, and Geophysical Agency recorded at least 25 aftershocks.
• Several landslides were reported around Cianjur.
• Indonesia, the country of more than 270 million people is frequently struck by earthquakes, volcanic eruptions and tsunamis because of its location on the “Ring of Fire,”
• It also caused panic in the greater Jakarta area, where high-rises swayed and some were evacuated. Earthquakes occur frequently across the sprawling archipelago nation, but it is uncommon for them to be felt in Jakarta.

Pacific Ring of Fire

• The Ring of Fire, also referred to as the Circum-Pacific Belt/Zone, is a path along the Pacific Ocean characterized by active volcanoes and frequent earthquakes. Its length is approximately 40,000 kilometers.Circum- Pacific Zone
• Seventy-five percent of Earth’s volcanoes—more than 450 volcanoes—are located along the Ring of Fire.
• Ninety percent of Earth’s earthquakes occur along its path, including the planet’s most violent and dramatic seismic events.

Location

• It traces 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, runs down the eastern coast of Asia past New Zealand and into the northern coast of Antarctica.

The Ring of Fire is a direct result of plate tectonics:

• Along much of the Ring of Fire, plates overlap at convergent boundaries called subduction zones. That is, the plate that is underneath is pushed down, or subducted, by the plate above. As rock is subducted, it melts and becomes magma. The abundance of magma so near to Earth’s surface gives rise to conditions ripe for volcanic activity.
• Transform boundary: The border between the Pacific and North American Plates is a transform boundary, where plates move sideways past one another and generates many earthquakes as tension in Earth’s crust builds up and is released.
• Consumption of oceanic lithosphere at these convergent plate boundaries has formed oceanic trenches, volcanic arcs, back-arc basins, and volcanic belts.