On the one hand earthquakes remove tension from the earth’s crust and release energy that can’t be used in future shocks.

On the other hand, if a shock doesn’t release all energy it may come to rest in a relatively weak spot that will soon give away again (https://en.wikipedia.org/wiki/Earthquake_swarm: “The Matsushiro swarm lasted from 1965 to 1967 and generated about 1 million earthquakes. This swarm had the peculiarity of being sited just under a seismological observatory installed in 1947 in a decommissioned military tunnel. It began in August 1965 with three earthquakes too weak to be felt, but three months later, a hundred earthquakes could be felt daily. On 17 April 1966, the observatory counted 6,780 earthquakes, with 585 of them having a magnitude great enough to be felt, which means that an earthquake could be felt, on average, every two and a half minutes.”)

Because of that, I think an earthquake will increase the probability of one occurring again soon, but decrease its strength.