[It is feared / People fear / People are afraid] that 18,000 (people) are buried in (the) city near (the) epicenter (of the earthquake).
to be afraid that or to fear that is used to present unpleasant news that is cause for concern or worry, even though the news does not actually frighten anyone.
I'm afraid that you have failed the exam.
I fear that all of them have been lost at sea.
I'm afraid that we won't be able to take the vacation we had planned.
In newspaper headlines feared often occurs with this meaning before a past participle or adjective indicating something unfortunate.
feared dead, feared lost, feared missing, feared killed, feared murdered, feared buried, feared drowned
CJ