The Orange alert level (Advisory) indicates that an earthquake with a magnitude greater than or equal to 5.5 has occurred, and that the expected effects on a given stretch of coast due to a possible tsunami could be minor (the expected run-up is less than 1 metre).
When the seaquake has these characteristics, there is a real danger for people who are near the coast, especially if in areas not much above sea level.
The Orange alert (Advisory) corresponds to a smaller evacuation area than the one provided for by a Red alert (Watch). In any case, the Orange alert does not mean that you should not evacuate the area, but only that the area affected by the evacuation is smaller.
When the Orange alert is issued for a certain stretch of coast, this does not exclude that the Red alert is in effect elsewhere. The difference in the alert levels currently issued through the Decision Matrix depends, for each earthquake of a certain magnitude, on the distance of the forecast points from the epicentre.
For this reason, the warning messages indicate the different alert levels for each region and for each forecast point, in descending order.
For the definition of the thresholds of the alert levels according to the magnitude, the depth and the distance from the epicentre, see the Decision Matrix table.