The whole of Northeast India falls in Seismic Zone V, the highest earthquake risk category in the Indian code. That does not mean you cannot build safely here; it means safety has to be designed in from day one.
Start with a simple, regular plan
Buildings with a regular shape and evenly placed columns behave far better in an earthquake than L-shaped or irregular plans with heavy cantilevers. Your architect and structural engineer should work together on the layout, not one after the other.
Follow the code, and check on site
Ductile detailing as per IS 13920, proper lapping and anchorage of steel bars, and good-quality concrete make the difference between a building that cracks and one that collapses. Regular site supervision is just as important as a good drawing.
Do not ignore the traditional wisdom
Lightweight Assam-type houses with timber and bamboo frames have survived major earthquakes for generations. Many of their ideas, such as light roofs and flexible frames, are still relevant in modern design.