This should happen at some point as you play through the campaign. In one of my duties, an earthquake occurred and caused a whole bunch of things come up in quick succession. Mostly fire and fire with ambulance. Very few police tasks came up during the event.
You'll know an earthquake when it happens, the whole screen shakes. I do not know at this point if it's random or if it always occurs in the same part of the campaign.
So far, this is the only duty that I've surpassed 100 rep. I've now done this on a few different games. Usually big cities and/or late in the campaign. On the more frantic duties where this is possible, I find that pausing the game a lot helps me stay efficient.