The decollement rupture area of the 1833 event is likely the same as in 2015, but closer to Kathmandu. Both earthquakes occurred along the Main Himalayan Thrust, and unlike the 1934 quake, did not rupture to the surface, thus, were blind thrust earthquakes. Inferring from isoseismal maps prepared after the quake, researchers believe the earthquake was caused by an 80 km to 120 km long by 40 km wide section of the megathrust fault rupturing. The same fault patch that broke in 1833 would re-rupture again during the 8.0 1934 Bihar earthquake, as it did little to release the elastic tension along the decollement.