On Friday, thousands of people prayed at mosques and mass graves in Aceh in remembrance of those who died four years ago. A tsunami drill was held in Gorontalo, north Sulawesi, on Friday, in which at least 5,000 people took part.
Experts have said Indonesia's disaster preparedness is a work in progress and large parts of the country are still not covered.
The country's early warning system has two out of a total of 10 planned buoys in place.
The government aims to deliver tsunami alerts within five minutes of an undersea quake, but experts have said that cannot be achieved until Indonesia has installed at least 22 buoys, 120 tide gauges with digital recordings, and 160 seismographs.
Marta Karouw was one of about 2,000 Indonesians who gathered in the city of Manado, on the northern tip of Indonesia's Sulawesi island, on Saturday morning to practice and prepare for the unthinkable -- a huge tsunami.
The drill comes one day after the fourth anniversary of the devastating Indian Ocean tsunami that smashed coastal villages in parts of Asia on Dec. 26, 2004, killing about 230,000 people.
Indonesia's archipelago, in an area of intense seismic activity, is particularly vulnerable to earthquakes and the risk of another tsunami just like the one in 2004.
Much of Aceh province on the northwestern tip of Sumatra, was devastated by the 2004 tsunami. About 170,000 people died or went missing, and the area is still struggling to recover.
Since then, Indonesia's government has taken measures to improve readiness for such disasters. It has installed an expensive warning system, and staged periodic evacuation drills.
"I learnt where to flee and to stay calm in order to be able to save myself and my family, and to get medical help if needed." said Karouw, 38.
Some 15,000 people had been expected to attend the Manado tsunami drill on Saturday, but heavy rain kept many away. Sirens boomed to signal a magnitude-8 earthquake, sending people scurrying through the pouring rain to higher ground for safety.
Police and soldiers kept order and simulated the rescue of those trapped inside a shopping mall and in two-storey shops, while emergency services were tested for their readiness.
Last Mod: 28 Aralık 2008, 11:46
"The simulation helps me know what to do in this kind of situation, it's really useful," Karouw said.
The last time Manado's inhabitants felt a quake was just a few months ago when a 7.6-magnitude tremblor struck near Ternate, a small island about 290 km (180 miles) to the east.