Two quakes with magnitudes of 5.7 and 5.1 struck off eastern parts of Indonesia earlier Monday, the Meteorology and Geophysics Agency reported here.The 5.7 magnitude quake rocked at 01 : 53 a.m. Jakarta time Monday (1853 GMT Sunday) with epicenter at 50 km southwest Oksibil of Papua and with the depth at 14 km, the agency said.The other quake jolted at 04 : 45 a.m. Jakarta time Monday ( 2145 GMT Sunday) wih epicenter at center at 57 km southwest Ambon of Maluku and with the depth at 165 km, it said.Indonesia sits on a vulnerable quake-hit zone so called \"the Pacific Ring of Fire.\"