Alternative Explanations and Conclusions
Once researchers realized that an earthquake could not be blamed for the large tsunami, the other explanation they came up with was an undersea landslide.
To test this theory they:
- conducted many interviews with the survivors
- People on shore revealed the loud, long noise that was far too long for an earthquake.
- Witnesses also revealed that the first wave struck a full 20 minutes after the earthquake which is much longer than a tsunami generated by an earthquake.
- conducted surveys of the ocean floor to look for evidence of a slide.
- A team mapped the bathymetry of the sea floor and found many pieces of evidence that confirmed their theory of an undersea landslide.
- One survey found a large, fresh, bowl shaped void in the sea floor slope.
- There was also evidence of very recent movement along one of the nearby faults.
Conclusions
It is now generally accepted that the 1998 tsunami was caused by an undersea landslide although there are a few skeptics who say that there still is not enough evidence. Despite these few, this tsunami, opened many people's eyes to the fact that large tsunamis can be generated from landslides and not just earthquakes. With this event, and the latest tsunami in Indonesia, more monitoring systems are being put in place in this region of the world with hopes of being able to better warn people in harms way.
