The quake hit at about 3:03pm southwest of the capital Honiara
The deal could see China deploy police and military personnel in the Solomon Islands.
Mahuta said the agreement was concenring.
Senior US delegation met with Solomon Island leaders.
In a media release, the government confirmed it is expanding security arrangements with more countries, including China.
Trade Minister David Parker says he hasn't received any requests for assistance from the Solomon Islands Government.
The curfew will start on Saturday night and will go from 7pm to 6am and be repeated every day until it is revoked.
Protests have been held over a 36-hour lockdown for the country.
