The 7.8 magnitude aftershock came just one day after an 8.2 quake struck the region.
Chile’s emergency office and navy have issued a tsunami warning.
Wednesday, officials surveyed the damage from the initial earthquake.
Six people died in the quake.
The mayor of Alto Hospicio said more than 2,500 homes have serious structural damage.
The quake generated a two-meter high tsunami in some coastal areas and caused landslides as well as power outages.