I don't see any confusion there. The "length" of the crack is its long dimension, from end to end, and the "width" is how far the two sides have spread away from each another.
"And as it grew, also became wider — by 2015, yawning some 200 meters in length."
They use "wider" and "length" to describe the same 200 meter span.
The correct word for a measurement of wideness is width.
Length [NOUN]: 1. the longest extent of anything as measured from end to end: the length of a river. 2. the measure of the greatest dimension of a plane or solid figure.
It's pretty unambiguously wrong. You can back into what the author meant without ambiguity, but that doesn't mean the author used the correct word.