A system for monitoring a borehole in an earth formation includes: a borehole string configured to direct a fluid into the earth formation; at least one optical fiber sensor disposed on the borehole string at a fixed location relative to the borehole string, the optical fiber sensor including a plurality of measurement units configured to generate measurements of at least one of strain and deformation of the borehole string; at least one temperature sensor configured to measure a temperature at a plurality of locations along the length of the optical fiber sensor; and a processor configured to receive the measurements from the at least one optical fiber sensor, receive temperature measurements from the at least one temperature sensor, and identify a fluid leak in at least one of the borehole string and the formation based on a correlation of the optical fiber sensor measurements and the temperature measurements.