A usually elongated depression between geologic faults.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "graben" in a sentence
"Faults like these cause troughs to form, called graben, of which the heavily shadowed one is a good example."
"What the new images show are the existence of "graben," massive valleys crossing the crater in an east-west direction, some up to a mile and a half wide."
"They show that the bounding faults of the "graben" cut the Chumstick Formation and that the southwestern bounding fault really is a composed of northwesterly trending reverse faults and younger northerly strike-slip faults, both of which cut northwesterly striking folds in the Chumstick Formation."