Earthquakes typically last only a few seconds, although sometimes the shifts in the subsurface occur in slow motion. Understanding these 'slow quakes', known as 'slow slip events', and their interplay with the short—sometimes violent—tremors is critically important to define the seismic hazard and subsequent risk. An international group led by Patricia Martínez-Garzón, Junior Group Leader at the GFZ German Research Center for Geosciences, has now published a study in the journal Seismological Research Letters in which they investigate this interplay of different seismic events near the metropolis of Istanbul with its millions of inhabitants.