I have been asked to provide some details about the sacralization of the underground fire through the divine couple Maia/Volcani. I have been asked about the possibility to identify these Deities with the geothermal heath of the Earth and with lava.
Just at a first step, I could say that, according to an exoteric point of view, this similarity could be even possible. Nonetheless Maia and Vulcan, according to an esoteric and a deeper spiritual/religious perspective, have a value and a symbolic meaning defitively more complex.
Maia and Volcan are linked to two different kind of underground-inferi "heat" and "fire". Of course these "fire" aand "heat" have to be interpreted as occult and super-natural fire and heat rather than physical, profane and vulgar phenomena.
The current month of May is dedicated to Maia: so, in this occasion, I can provide just few details about fire and heat sacralized in the male polarity of Vulcan which are essentially Earth promordial energies capable to "ignite and empower the metals". This is an underground force thus connected to metals (in an esoteric sense) and to their symbolic properties: just think about the metallurgic myth of Vulcan (the "Blacksmith") and the symbology of the weapons he forges and shapes.
The fire and heat sacralized by Maia show different features. Even in this case, we are talking about occult, underground, hidden, infernal forces but not linked to metals: "everything depends" on these forces. While the Vulcan's fire and heat burn and forge, the Maia's ones do not burn and forge. This fire and this heat are subtle and mild. These are continuos interior forces. This is a fire without light. This is a heat coming from the inside propagating everywhere underground wrapping up everything like a mild fewer. It is a sensation of something perpetually and slowly burning somewhere in an occult, remote and deep place inside the Earth.
It's better to define it "tepor" (warmth), rather than "heat", nourishing all the Nature: it is a warmth generated by the "Earth's Blood" moving from her Deep Heart and diffused everywhere underground through the veins and capillaries of the Earth.
This tepor is at the base of life, growth and development of all the expressions of Nature. Everything created, produced, emanated is provided with tepor, the Maia's warmth.
It is important to remind that Great and Small are the same: the macro and micro dimensions are the same. For this reason the cosmic and Naural dimensions are similar to the human one.
We thus find this tepor in anything provided with Life: this warmth is diffused through the body opposing to the cold status of Death. Not surpisingly any sacrifice (i.e. a libatio) involves the act of burning the offering on a fire because it makes visible this foundamental aspect of life.
This tepor, generated by a fire without light, is also an enthusiasm, a passion, a fervor. It is a warmth linked also to friendship and love ("warmly" is said in the common language). It is thus the warmth of love opposed to the cold rationality. It is the warmth of the "sacred breath" (flamen), pouring Life: it is the sensation to be alive. It is also the warmth produced by meditative and contemplation practices.
Maia is therefore a vital force irradiating in the Earth Depth as well as inside us through the blood.
Like the lava produced by a Volcano destroys everything but representing however the foundamental base for the creation of an extremely fertile field, similarly the heat and fire of Maia can become a devastating force when too powerful.