This seems ungrammatical. I think the apostrophe on analysts' is a typo, and I would further rephrase the sentence:
Terrorism is often 'available', in the sense that risk analysts use the term,...
Terrorism is often 'available', in the sense in which risk analysts use the term...
because the idiom is to use a term in a particular sense. Consider this quotation from C. S. Lewis:
Faith, in the sense in which I am here using the word, is the art of holding on to things your reason has once accepted, in spite of your changing moods.
The author is trying to say that risk analysts use the word available with a special meaning, and that this special meaning applies to terrorism.
Better yet, and more concise:
Terrorism is often 'available' (in risk analysts' sense) in large part because of media coverage.