How do you study the Earth's crust below the ocean? Well, you use a drill. A very, very long drill attached to a boat floating free out in the middle of the ocean.
It's easy to study the Earth's crust if the samples you need come from here, on land. But if you need samples from the three-quarters of the Earth's surface covered by ocean, your options are fairly limited. That's where the Integrated Ocean Drilling Program (IODP) comes in. IODP is an international scientific partnership that drills into the sea floor to get samples to study.
What are these scientists looking for? Why are they trying to find this mysterious gabbro? And what is the MOHO anyways?
Why is is so hard being a drill bit?...or...what I had to go through thousands of feet below the ocean floor.