Tag: OCRAL-Hazards

Anuk Krakatoa Tsunami, Indonesia

Link to A Level Geography Syllabus – Hazards – Tsunami’s caused by explosive eruptions (OCR).

When: Saturday 22nd December 2018, 9:30PM

Where: Off the coast of Indonesia causing an impact on the Pandeglang region of Indonesia.

Location of the Volcano
Source: https://www.dailymail.co.uk/news/article-6525675/At-281-dead-Child-Krakatoa-volcano-explodes.html
Source- Guadian, 22nd December 2018

Cause:

Source
  • Volcano ‘Anak Krakatau’ erupted which is located on a plate boundary where the Indo-Australian Plate subducts under the Eurasian plate.
  • The eruption triggered an undersea landslide when the southwestern side of the volcano collapsed triggering a tsunami wave.
  • This occurred as the volcano is above a steep submarine slope created by the 1883 eruption.
  • The height of the wave was exacerbated by an abnormally high tide because of the full moon.
  • This has been a site of frequent eruptions since 1827.
Image Source: https://anakkrakatau-krakatoa.weebly.com/plate-tectonics.html

Impact:

  • Wave 20ft high that came 15-20 metres inland.
  • Early warning system did not activate meaning that people were unprepared; this is as they were designed to protect from earthquake triggered tsunami. As this occurred at night people could not see the ash plume and steam explosions and therefore people were taken by surprise.
  • 222 People confirmed dead.
  • 843 people injured.
  • Roads blocked by debris, disruption to water supplies and houses destroyed.

Other Information

This is an area that is extremely tectonically active; there have been other earthquakes and tsunami’s this year. This also comes 14 years after teh Boxing Day Tsunami of 2004 in which a 9.3 magnitude earthquake killed 220,000 people in countries around the Indian Ocean. The volcano Anuk Krakatau has been growing since it breached the surface in 1928. There have been several eruptions that have created overlapping cones, the most recent prior to December was in May 2018.