THE devastating Indian Ocean tsunami of 2004 may have been made worse by springy sediment on the seabed.
Sediment is more elastic than the hard bedrock of the Andaman Sea, where the quake occurred. As a result it can act like a spring during an earthquake: if a piece of bedrock slips downwards, for example, the sediment is briefly stretched out vertically before collapsing and compressing. The effect is to amplify the movement of bedrock, generating a larger wave than would otherwise occur.
This could explain why the 2004 tsunami was far stronger than predicted by computer models of the…
