A 7.5 scale earthquake erupted off the island of Sulawesi a few minutes after 6 pm on Friday, 28th September, resulting in a massive tsunami with six meter high waves. The country was still slowly recovering from the aftermath of another devastating 6.9 earthquake that struck Lombok less than two months earlier on August 5. Widespread death and destruction followed the September 28 earthquake. More than 1400 people lost their lives. Severely affected areas included Palu, Lombok, Donggala and Balaroa. Many were injured. Tens of thousands of homes were destroyed. Shortage of food, water and fuel was widespread. People in the disaster struck regions grew increasingly desperate for supplies, especially medical aid. A 14 day emergency was announced. The country’s president, after much reluctance, agreed to open doors to foreign aid from the international community.
Indonesia’s proximity to the Sunda arc – a volcanic belt located at the convergent boundary between the Indo-Australian plate and the Eurasian plate – makes it particularly prone to calamities such as earthquakes, tsunamis and volcanoes. The country is located along the Pacific ring of fire. This is where a major portion of the world’s earthquakes and volcanic eruptions occur owing to intense tectonic activity. The effects of the tsunami and earthquake were intensified in Palu, one of the most severely affected cities in the region owing to its narrow bay and low lying terrain.
What went wrong?
Indonesia does have an earthquake and tsunami warning system installed along its coast to avert widespread disaster. Yet, the earthquake and following tsunami exposed many flaws and inefficiencies in its working that aggravated the situation. Government officials claimed that alerts and warnings were sent out repeatedly to the locals. However, widespread damage to power lines and telecommunications infrastructure in the area raised serious doubts regarding the veracity of this statement. Many Indonesians took to social media to voice their disappointment.
Seismographic Sensors – These are devices that quantify the magnitude of seismic vibrations of different amplitudes and frequencies. Tremors in the earth’s surface cause a suspended mass of substantial weight to be displaced along the three axis of three dimensional space. A seismogram records this displacement. The information recorded by seismograms is used to locate the epicenter of earthquakes and their magnitude.
Although the earthquake was detected and an early alert was relayed, text message warnings via cell phone could not be sent out in time owing to severe damage to the cell phone towers in the region.
Buoys – Buoys are tsunami detection instruments used to monitor and archive changes in deep sea in order to spot approaching tsunami waves that are caused by underwater earthquakes.
These devices are based on the DART (Deep Ocean Assessment and Reporting of Tsunami) technology that was developed by the Pacific Marine Environmental Laboratory (PMEL) of the National Oceanic and Atmospheric Administration (NOAA). They comprise of two independent and redundant, backup communication systems that record sub-millimeter sea level changes in deep sea.
These buoys can be remotely controlled, enable system troubleshooting and research activity thanks to a two way communication system between the device and the central monitoring location.
A pressure monitoring device located at the ocean bed detects changes in sea level based on the rise and fall of water pressure. This information is transmitted to a second component located at the surface which passes on the information through satellite communication to a central monitoring location.
Buoys have a useful life of roughly three years and need to be replaced and maintained on a regular basis.
All the 22 buoys installed in Indonesia’s open waters provided no data or warnings whatsoever. None of them have been operational for more than at least 5 years due to neglect, lack of maintenance and a disregard for public safety.
Tidal Gauges – These instruments are equipped with multiple sensors that monitor the water level in the surrounding areas. Besides detecting approaching tsunamis, tidal gauges are also used for a variety of purposes such as warning seafarers of unsafe weather conditions for navigation, restoring and preserving underwater ecosystems and so on.
There were no tidal gauges in Palu’s immediate vicinity along the coast that could provide accurate information – the nearest installation was located hundreds of kilometers away and recorded only marginal changes in sea level. Hence, based on this information, officials lifted the initial tsunami warning that had been issued shortly after the earthquake.
The September 28 earthquake and tsunami seriously exposed the country’s lack of efficient disaster mitigation and recovery capabilities despite being located in a hazard prone zone. Distributing much needed emergency supplies, especially to people situated in remote and far off regions proved to be a major challenge. The existing early warning system that is currently in place has suffered prolonged wear and tear over the years and desperately needs a technical and infrastructural upgrade. Many are even considering incorporating disaster response training into higher education curriculums.
Preventing damage of such colossal proportions costs money and requires investments in terms of capital, infrastructure, resources and the creation of awareness. The country must be prepared take stock of the situation and implement adequate measures lest history repeat itself again in the future.