As far as I know there is no such concept as an apocalypse in Sanatan Dharma. Sanatan Dharma, however talks about “Pralaya” meaning upheaval. More importantly destruction of the existing in order to make way for the creation of new.
Pralaya can be seen in multiple ways.
- Physically it can mean major geo-climatic events which cause major upheaval ensued by changes of the geography as we know it. E.G. Being shifting/interchanging of poles, fault lines to cause quakes, etc.
- A paradigm shift in how we perceive things around us which can bring about major change in the outlook we have towards the world or each other can also be called Pralaya, but of the mind. This may lead to dissolving of geographical boundaries and emergence of a unified world order which is truly global.
- Pralaya can also mean the dissolution of an ideology in its totality giving birth to a new one which is a huge improvement on the previous one.
So any radical change which give a new direction to the world or to our civilisation as a whole can be called Prayala.