The 1999 Chi–Chi earthquake (Taiwan) and the 1999 Kocaeli earthquake (Turkey) caused much damage to infrastructure via surface rupture. Various strong-motion prediction methods have been proposed and standardized. However, few studies explored the influence of shallow fault rupture behavior on strong ground motions and occurrence of surface rupture. The rupture behavior of shallow faults is still poorly understood, and the evaluation of earthquake ground motions of inland earthquakes, including shallow faults, requires further development. Dynamic fault rupture simulation, which models rupture behavior based on the balance of the forces on the fault plane, is an effective method for addressing this problem. In this study, we first set parameters that can simulate observation records at K-NET Hakuba station and earthquake magnitude for the 2014 northern Nagano Prefecture earthquake, a reverse fault earthquake that caused a surface rupture. Then, we modeled the effects of different asperity locations and the presence or absence of shallow asperities on the earthquake magnitude and occurrence of surface rupture. The results show that even small-magnitude earthquakes can cause surface rupture if the asperity location is shallow, and that surface rupture may be larger if another asperity exists in the shallow area.