Can Lavos's eruption site be pinpointed?
One question that often is raised in discussion is the exact location of Lavos's eruption. Before going on, it's important to note that the 1999 A.D. map presented in Chrono Trigger in the Day of Lavos recording is not reliable. This is because it was created with the 600 / 1000 A.D. maps in design, mimicking exactly the configuration of the continents during those eras. However, the 2300 A.D. map indicates a largely different arrangement. Medina has seemingly rotated to the upper left counterclockwise to link with northern Zenan, whose left shore has eroded. This rotation does not include the area where Melchior's Hut was situated, as it now contains the Keeper's Dome and Sewer Access. Southern Zenan is largely missing, though evidence suggests it still existed before the apocalypse (the presence of a ruined skyscraper at the Sun Palace, which rose from the ocean floor). Apparently, Lavos's eruption decimated southern Zenan. Lastly, the continent of Choras is almost completely wiped out, save for the Geno Dome, suggesting that it also underwent duress from Lavos's eruption. Here is the full comparison of eras; it illustrates the discrepancy:
With these points cleared, JossiRossi attempted to locate the exact site of Lavos's eruption on the 2300 A.D. map to provide a reference and estimation of proximity to Death Peak. He firstly placed the 1999 A.D. map over the 2300 A.D. layout.
Then, we can judge where Lavos erupted from the Day of Lavos recording itself (or a confrontation with Lavos in normal gameplay).
The location is around 5 to 7 tiles above Death Peak, which roughly correlates. Death Peak appeared only after Lavos erupted. It is very spiky in its appearance; Belthasar also remarks that Lavos reigns atop the peak, where it spawns new creatures soon to depart the planet in search of new homes. Judging from these facts, it is somewhat logical to conclude that Death Peak is Lavos's shell on the surface with three hundred years of accumulated matter on top. The spawn appear directly on Death Peak from within Lavos's shell. Sadly, there is not a direct statement to corroborate this assumption, but an explanation still exists -- specifically, that Lavos, after breaking the planet's crust, caused an upward magma flow that created a new mountain at the site of the appearance.
From: Theory (Locations)