NEW YORK — Sometimes it's a fast-moving ooze: A street becomes a stream, grows into a river and then a raging mountain of moving debris. Sometimes, it's a wet curtain of water crashing over a shoreline, tossing trees, ships and cars casually aside as a child would a stack of Lego.

Until a week ago, a tsunami was one of the most mysterious of natural events, its devastating power usually evident only in the aftermath. Yet from the first moments the Earth started to shudder on March 11, Japan's tsunami was one of the most recorded disasters ever to be captured on film, lending a visual power to storytelling unmatched since the Sept. 11 terrorist attacks almost a decade ago.

Quake footage was available almost instantly: Office workers running outside as building chunks slammed to the ground; skyscrapers swaying like evergreens in a windstorm; pictures falling off walls; store stock spilling to the floor.