To trigger a tsunami early-warning system for a specific earthquake we need to ask three questions. The first questions is – the location of the earthquake, was it on land or in water? For an tsunami early warning system to trigger a tsunami warning we need the earthquake to be in the water. The second question is – is the magnitude of the earthquake above eight or less than eight? If it’s a more than eight we’re obviously concerned about a potential tsunami. If it’s less than eight there’s less potential for a tsunami. And the third question is that what is the type of earthquake? Is it a thrust earthquake or a strike-slip earthquake? A thrust earthquake is actually able to generate a tsunami For the case of the tsunami in Sulawesi in Indonesia in September 2018 the answer to the first question was yes but the answers to the second and third questions were no because the magnitude of the Sulawesi earthquake was 7.5 which is a moderate earthquake in terms of tsunami genesis and also the type of earthquake was a strike-slip earthquake, not a thrust earthquake That’s why the tsunami early warning system was not triggered But! the Sulawesi tsunami was generated and killed 2000 people The reason for that was that, because of the shaking of the earthquake and the instability brought about by the earthquake some of the seafloor slopes experience instability and they failed. Because of the failure of the seafloor slopes, a large amount of mass, like here, moved downward, and because of this moving, sliding mass, a large wave was generated.