The lessons from Palu | Sunday Observer

The lessons from Palu

Waves as high as six metres caused massive destruction
Waves as high as six metres caused massive destruction

Another day, another tsunami. The number of people known to have died in Indonesia in last Friday’s earthquake and tsunami has risen to more than 1,200, the country’s disaster response agency said. The death toll jumped on Tuesday from a previous confirmed figure of 844. The 7.5-magnitude quake struck just off the central island of Sulawesi, setting off a tsunami that hit the coastal city of Palu.

Although Sri Lanka was spared this time, we still have bitter memories of the 2004 Indian Ocean Boxing Day tsunami, which claimed around 250,000 lives in the region, including 40,000 in Sri Lanka. Since then, there have been several tsunami warnings for Sri Lanka, but no tsunami has occurred.

Coastal

However, both Indonesia and Japan had experienced tsunamis since then. We too have to be ready all the time – a tsunami drill was conducted in coastal areas just last month.

But, the problem is, things can go drastically wrong even with a tsunami warning system in place. A tsunami warning was sent out by Indonesia’s meteorological and geophysics agency BMKG - lasting just over 30 minutes - but it appears to have drastically underestimated the scale of the tsunami that would follow.

Palu - a city in Sulawesi located in a narrow bay - was hit by waves as high as six metres. The water brought buildings down and caused massive destruction. Making things infinitely worse, hundreds of people had gathered for a beachfront festival. Waves went over the beach sweeping everything in their path.

Many critics have accused BMKG of lifting the warning too early, though the agency says the waves hit while the warning was still in force. BMKG chairwoman Dwikorita Karnawati told the Jakarta Post that the decision to end the warning was made after the agency received information about the tsunami, including a field observation made by a BMKG employee in Palu.

There seems to have been a combination of rather unfortunate factors at play here. There are fears that though the alert was sent out, and according to the communications ministry, repeated tsunami warnings were sent to residents via text message - they might not have been received.

Communications

This is a lesson that Sri Lankan authorities must also look at. Sending a text to 20 million phones may not be as simple as it sounds – a spokesman for BMKG said the quake had brought down the area’s power and communications lines and that there were no sirens along the coast, which might have rendered the alerts essentially useless even if received. Sri Lankan authorities must also study the attempts being made in the US to send a Presidential Emergency Text to 300 million Americans.

Another factor is that critical components of the expensive early warning system may have not been working properly due to natural damage and even vandalism.

Although Indonesia has an advanced tsunami warning system, including a network of 21 buoys which would have dispatched advance warnings based on data gathered by deep sea sensors, none of these buoys - donated by the US, Germany and Malaysia after the devastating 2004 Indian Ocean tsunami - are working.

The rest of the country’s early warning system comprises 170 seismic broadband stations, 238 accelerometer stations and 137 tidal gauges or buoys. But, in a stark admission, BMKG’s head of earthquake and tsunami centre said the current system in place is “very limited - our [current] tools are very lacking”. The system also failed to accurately gauge the scale of the tsunami. BMKG revealed that the closest tidal gauge to Palu was well over 200 Km away.

Sensors

The third factor, which is common to most developing countries, is the lack of a maintenance budget for systems such as these. The BMKG admitted that of the 170 earthquake sensors, it only has a maintenance budget for 70 sensors. Sri Lankan authorities must urgently assess the operational capability and readiness of the early warning system in the wake of this incident. Any Budgetary constraints must be immediately addressed regardless of the costs involved since the latest disaster has highlighted the costs of not having implemented a more sophisticated early warning system.

There is another aspect – the very unpredictable nature of tsunamis and earthquakes, which anyway cannot be predicted. This is not the kind of earthquake that typically generates a major tsunami, according to Prof Philip Li-fan Liu, vice-president of the department of civil and environmental engineering at the National University of Singapore as quoted by the BBC.

Tsunamis are typically only generated when there is a large vertical displacement but in this case, the tectonic plates were rubbing against each other horizontally, and when that ruptures it only creates a significant horizontal movement and not a significant vertical movement. We indeed have a long way to go before we have a more comprehensive understanding of tsunami-inducing earthquakes.

Research

The Indian Ocean countries and Japan must thus intensify research on earthquakes and tsunamis and collaborate more closely with well-known bodies such as, the US Geological Survey (USGS) which has the world’s most sophisticated tsunami warning network.

In fact, it was the USGS which sent a warning over the 2004 Boxing Day tsunami, which no one in the 14 affected countries cared about.

We must also be wary of Climate Change which can cause low-lying cities to go underwater. There will be a greater threat of landslide tsunamis as some of the melting glacial mountains can topple into the sea, generating massive tsunamis.

With a wave run-up of nearly 200 metres, the tsunami that ripped through an Alaskan fjord in 2015 was one of the largest ever documented. But, with no-one killed, it almost went unnoticed. It was triggered by a massive rockfall caused by the melting of the Tyndall Glacier, which experts say has given them the clearest picture to date of a landslide generated tsunami.

Accurate earthquake prediction remains the Holy Grail of scientists. Forecasting an earthquake’s approximate date assumes that earthquakes follow some kind of pattern — that faults release pressure in a predictable way. But this does not always happen.

Unlike us, animals seem to be having a sixth sense that can give them an indication of an impending disaster, well before any of our advanced gadgets. In fact, no animals perished in the 2004 tsunami except those who were tied or caged.

Humans have lost this sense in the course of evolution, so we have to rely on technology instead. There is even talk of using Artificial Intelligence, somewhat akin to the animals’ sixth sense, to predict earthquakes at least a few minutes in advance. We hope these efforts succeed, because that would mean more lives can be saved.

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