On 11 January 2018 (18:26 UTC), a Mw 6.0 earthquake occurred approximately 30 km west of the Sagaing Fault in the Bago-Yoma Range (BYR). Using a local broadband seismic network and regional seismic stations, we refine the source parameters of the earthquake sequence. We relocate ~100 earthquake epicenters and determine the focal mechanism and centroid depth of the mainshock and 20 aftershocks with Mw>4. The relocated epicenters are distributed in an elongated zone oriented in a NW-SE direction that is consistent with the strike of the mainshock fault plane solution and the slip distribution derived from ALOS-2 InSAR observations. Most of the aftershocks have a pure thrust focal mechanism similar to the mainshock, except for four strike-slip aftershocks. The refined source parameters of the thrust events clearly delineate a fault dipping ~40˚ to the southwest at a depth range of 3-7 km, indicating that the earthquake sequence ruptured a previously unmapped, active fault. We interpret the earthquake sequence to be associated with pre-existing faults within the BYR anticlinorium. This earthquake sequence and historical seismicity indicate that the upper crust of the BYR is highly stressed, resulting in ongoing distributed deformation between the oblique Rakhine megathrust and the dextral Sagaing Fault. The seismic hazard posed by these active faults has been increasing with the development of infrastructure such as dams within the BYR. Our study highlights the need for high-resolution earthquake source parameter and strong ground motion attenuation studies for seismic hazard preparation and further understanding of the neotectonics of Myanmar.