Mountains &amp; canyons were produced by events that occurred at a very short time span, like minutes to days whose causes are unknown (like earthquakes, floods, volcanic eruptions).
(canyons; were produced; by events) (events; occurred; L:at a very short time span) (days; are; unknown (like earthquakes, floods, volcanic eruptions)
canyons events days
were produced occurred are
by events
L:at a very short time span
unknown (like earthquakes, floods, volcanic eruptions