Los Angeles Mayor Eric Garcetti says the city’s earthquake early warning app will now alert users of weaker shaking.

The Los Angeles Times reports the change announced Wednesday comes after some residents were upset they didn’t receive notice before shaking arrived in LA from two powerful quakes north of the city on July 4 and 5.

The new threshold will trigger alerts on the city-owned ShakeAlertLA app when so-called “weak” shaking is forecast to arrive in Los Angeles County. That level of shaking is typically felt by people inside, especially on upper floors of buildings. It may not be felt by other people, especially those outside.

Officials say the app can make a difference if someone needs to pull over, get out of an elevator or drop, cover and hold on.