The statement is correct.
When a flood is giving a time-bonding term, such as the 100-year flood, in this statement, it means that it has been noticed that the floods from the particular river occur on approximately that much of a time span.
If there has been a flood recently, than it most probably means that there isn't going to be a flooding caused by that river for the foreseeable future.
Now, there's always exceptions, as the climate patters are changing constantly, and there's always surprises, but in general, in lot of regions of the world, there has been noticed a certain consistency in some natural occurrences.
Human activities directly contribute to landslides especially the kaingin system practiced by some farmers and the ruthless illegal logging for some loggers. These selfish practices harmed the nature causing soil erosion and worse landslides due to the absence of trees.
<span>Submerged basaltic volcanoes that are higher than 1 km
are called seamounts, letter D. They are underwater mountain formed by volcanic
activity. They do not reach the sea level and is not considered an island. </span>