The USGS said the quake struck the center of the island, Vanuatu's fourth largest, at 7:09 a.m. (2009 GMT on Wednesday) and was fairly deep at 124.4 miles (200 km), which would have dampened its effect.
Erromango has a population of just under 2,000 people.
The Vanuatu Meteorological Services & Geohazard Department said the earthquake caused no damage to the Pacific island nation.
The Pacific Tsunami Warning Center said the quake did not pose a tsunami threat.
The Vanuatu volcanic archipelago, east of Australia in the Pacific Ocean, is in the so-called Ring of Fire and prone to earthquakes.
The Philippine Institute of Volcanology and Seismology (Phivolcs) posted a Tsunami Bulletin, stating that there is no tsunami threat in the country. — Reuters With BAP, GMA News
