Nasution, H.A. et al. 2025. NUMERICAL ANALYSIS OF CONCRETE-FLY ASH AND CONCRETE-OPC IN MULTI- STOREY BUILDINGS DURING EARTHQUAKES. EINSTEIN (e-Journal). 13, 1 (Feb. 2025), 49–55. DOI:https://doi.org/10.24114/eins.v13i1.48769.