Bodies of rock move past each other on faults during an earthquake. Slip on one fault can increase the stress on others, thereby increasing the chance of a future earthquake. GPS-satellite observations measure the movement of the Earth’s surface in Sulawesi with high accuracy and show that such interaction took place following the devastating earthquake at Palu in 2018. We propose to focus and expand upon these observations in both space and time, and use new computer simulations to investigate this increase in stress, which is still poorly understood so far and paramount for correctly assessing seismic risk.