> Yes, the probability of tsunamogenic landslides do increase during earthquakes, but it's still quite unlikely for an event of this magnitude tens of km from the continental slope; this is why a properly-calibrated tiered system would be better

There is a tiered system, its calibrated based on a combination of magnitude and warning time for the initial alerts (updated notices are based on other measurements and observations, but if gathering and analyzing observations before an initial warning doesn't leave time to act on it, it doesn't matter how accurate the warning is.)