Hidden fault had amplified Tsunami

Five years ago, The disaster had killed over 2 lakh people

Hidden fault had amplified Tsunami

Five years ago, The disaster had killed over 2 lakh people

Scientists thought the culprit behind the deadly waves was the magnitude 9.2 Sumatra-Andaman earthquake, one of the most powerful ever seen. Over 2.3 lakh people died or went missing from 12 countries.

Small fracture

Now, it turns out the quake had help from a fault few scientists even knew existed.

Several new studies indicate that the much smaller fracture spawned a separate tremor that sent a 100-foot-high wall of water barreling into Indonesia's Aceh province.

Pick Of Destiny: Indonesian tsunami survivor Yuyun Sri Rochmasari plays with her eight-month-old son Ahmad Al-Ghifari at Lampuuk beach in Banda Aceh yesterday, on the eve of the five-year anniversary of the incident.

If true, the discovery would shed light on what really spawned the 2004 disaster.

The main earthquake broke along a 1,600-km section of fault where the India tectonic plate grinds underneath the Sunda plate. The fault is thought to have slipped 20 to 25 metres almost instantaneously.

Studies show

Felix Waldhauser of Columbia University and a team of researchers analyzed thousands of aftershocks in the area since 2004.

Epicentres from the small quakes lined up with this unusual fault, suggest that it, and not the main fault, has been active in this area since the disaster.

Crucially, this "splay" fault, slices through the Sunda plate much closer to Sumatra's west coast, and at a much steeper angle to the ocean floor than the main fault.

This means that whenever this splay fault breaks, it pushes the ocean floor upward more forcefully, causing a larger tsunami.

"Observations of the earthquake along the (main fault) were not enough to generate a tsunami that big," Waldhauser said.

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