The 1917 San Salvador earthquake occurred on June 7 at 18:55 local time near the Salvadoran capital.

Another Ms  6.0 aftershock was centered around San Jacinto Hill, close to the epicenter of the 1986 shock.

Their displacement rates were estimated to be as high as 11 mm (0.43 in) annually and Mw 7.2 earthquakes are possible on these faults.

Damage from the earthquake was mainly concentrated to the south of the fault while no major destruction was reported to its north.

[5] An area 30–40 km (19–25 mi) west of San Salvador volcano suffered the greatest damage inflicted by the initial earthquake.

[10] The earthquake was experienced by Colombian poet, Porfirio Barba-Jacob, who documented it in a book and the local newspaper Diario del Salvador.

[12]: 35  A fracture formed on the northwest flank of the Boquerón cone in the San Salvador volcano crater.

[3] The eruption produced an ash cloud and lava flow extended some 8 km (5.0 mi) along the northern slopes of San Salvador.

The eruption was the largest since 1671, and was possibly triggered by the earthquakes disrupting plumbing within the magma chamber.

[15] By 11 June, the eruption had generally subsided, and the lava flows affected a 16 km2 (6.2 sq mi) area, burying it under ʻaʻā.

One of these eruptive craters, El Tornador, located at 580–650 m (1,900–2,130 ft) in elevation, continued to produce lava and Strombolian explosions.