I don’t understand how something like this could happen again. Many of the people killed were on the beach when the wave hit. How can someone living in roughly the same geographic area where over 200,000 people were killed less than 2 years ago not recognize the signs of an incoming tsunami? How do you not notice the sea retreating when you’re on the beach?? I can understand people in their homes without communication being taken unawares but not someone sitting right next to the ocean. How sad. 
I was going to suggest there was no early warning but then I forgot about the receding sea levels.
If I saw groups of people running away from the beach yelling “Tsunami!”, I might get the hint, but perhaps it was the half hour delay that made others think differently?
Sadly, not all tsunami events have signs. If you have a “false ebb” - a downward ripple that precedes the wave - then you get a retreating sea. Many parts of Sri Lanka, however, didn’t have this luxury first time round. This could be the case in Java this time.
True, however, that anyone in a coastal region should evacuate the coast when they feel an earthquake - but Java is on a massively seismic area, and gets dozens of quakes a week.
The governmental “warning system” failure is what worries me, rather than individuals’ tragic lack of reaction to signs that might not have been there.
OK, didn’t see that the sea did in fact recede. In that case - God only knows. Having been in a tsunami-hit area last year, anyone shouting “tsunami!” (and it did happen) had me straight up the nearest hill. Then again, people could have become blasé.
Many of the people killed on the beach were locals. One would think they would know where the sea usually is and notice that it wasn’t where it was supposed to be. And realize that at some point, it would be back.
When the 2004 tsunami hit, I was surprised at the number of my friends who didn’t know that a quickly receding sea meant a tsunami was coming. I’ve known that since I was a child and I don’t even live anywhere near the ocean. It’s just one of those things I thought everyone knew from grade school earth science class.
Maybe my memory is fuzzy, but an awful lot of people wiped out in natural disasters seem to be locals who refuse to move. An old man with cats was prominent in one geography book chapter on the eruption of Mt St Helens.
Speaking as someone who lived for 2 years in a tsunami-hit region (Sri Lanka), I can tell you that human curiosity played a huge part in the body count. We saw a lot of men and children; the men because there had been a full moon the night before and they associated it with a lunar phenomenon – they walked out to smoke and talk. The children thought the receding sea was neat and walked out to pick up the fish standed on the seabottom and the shells. Then they couldn’t get to higher ground fast enough.
Have you READ that link? It talks about alien (UFO) activity to “correct the wobble of the earth” and other such nonsense as fact. Hardly a credible source.
"The government’s science and technology minister, Kusmayanto Kadiman, confirmed today that Indonesia had received bulletins from the Pacific Tsunami Warning Centre in Hawaii and Japan’s meteorological agency after the quake, but “we did not announce them”.
“If it [the tsunami] did not occur, what would have happened?” he said in Jakarta."
Um, maybe some lives would have been saved?
Yep. No aliens of any kind, just ordinary human stupidity.