A wellbore system includes a first fracture formed from a wellbore at a first location; a second fracture formed from the wellbore at a second location; a wellbore seal positioned in the wellbore between the first and second locations and configured to fluidly seal a first portion from a second portion of the wellbore; a pressure gauge positioned in the first portion; a pressure gauge positioned in or uphole of the second portion; and a control system configured to communicably couple to the pressure gauges. The control system performs operations including identifying a set of first pressure values recorded by the pressure gauge in the first portion during a hydraulic fracturing operation; identifying at least one second pressure value recorded by the pressure gauge positioned in the second portion during the hydraulic fracturing operation; based on the set of first pressure values and the second pressure value, determining fracture geometries of the second hydraulic fracture; and generating a graphical representation of the fracture geometries.