After A Tsunami

A recent trip to Indonesia took me to the island of Sulawesi. After some time in the Makassar area, we flew in to Palu, a city on the western side of the island. As our flight approached the airport, I wondered about very uniform residential areas I could see below me that seemed to have been built at a large scale. It was like the massive ‘cookie-cutter’ subdivisions seen in many parts of the United States, but rather unusual in other parts of the world. So what’s the story here?

We landed and began our 5-hour drive to Wuasa, near Lore Lindu National Park. As we drove through Palu, we saw damage to industrial and commercial buildings. What happened?

As it turns out, we were driving through a tsunami impact area, seven years later.

In 2018, a 7.5 magnitude earthquake struck about 70 miles northeast of here. It triggered a tsunami that came into a narrow bay and built strength before it hit Palu, at the bay’s far end. These events happened during rush hour on a Friday night and at the beginning of a weekend festival celebrating the 40^th anniversary of the city. People were traveling home from work and gathering at the beach for the festival. Instead of the forecasted waves of 2 feet or less, the actual waves reportedly reached the second floor of waterfront buildings.

Along with the tsunami, soil liquefaction occurred at an unprecedented level. As our local guide described it, “the ground just turned to liquid and swallowed up buildings”.

Between the earthquake, tsunami and liquefaction, an estimated 4,340 people perished.

The orderly subdivisions we saw represent rebuilding efforts to replace some of the more than 70,000 homes that were lost. The damaged non-residential buildings are still awaiting repair or rebuilding nearly seven years later. The impacts on Palu were certainly extreme, and exacerbated by the specifics of the timing and location. But the underlying forces are the earth’s plate tectonics. And increased development in bays and along shorelines places many more people in the path of tsunamis if they are in areas where the underlying geology is on the move. Communications systems must be in place to issue and update warnings for tsunamis and other dangerous natural events. Future development patterns, infrastructure and communications must all take these into account.