There are many versions of the mythology of Bhu Varaha. One version is Hiranyakasipu hid the Earth in the cosmic ocean and Vishnu took the board avatar to rescue the Earth.  Another version unable to bear the burden of the evils on the earth it sank in the Cosmic Ocean and Vishnu took Varaha form to restore the order.  It Bhu, The earth Goddess and one of Vishnu’s consort, sitting on his upper left elbow in Anjali Mudra. 

The iconography of Bhu Varaha dates back, at least, to the Gupta period, 3rd to 6th century of the common era. Bhu Varaha sculptures are very popular in the Central and North India till medieval time. 

According to  The Development of Hindu Iconography, by J N Banerjea, this form was earlier attributed to Brahma. It then got assigned to Vishnu reflecting the decline of Brahma’s worship and the ascendancy of Vaishnavism.

The idol is about 16.5 cm and it does not have much age. The idol is from Nepal.