This dataset includes results from U-Th disequilibria dating from zircon rims (outermost crystal face) and crystal interiors (polished crystals) of the last four explosive silicic eruptions from Ilopango caldera in El Salvador (TBJ, TB2, TB3, and TB4). Zircon crystals were analyzed employing Secondary Ion Mass Spectrometry at Heidelberg University.

Analytical Uncertainties are 1σ. ∞ = zircon in secular equilibrium (>350 ka)m = zircon-melt model isochron slope.Decay constants used: λ232: 4.9475·10−11 a−1; λ230: 9.158·10−6 a−1; λ238: 1.55125·10−10 a−1.Secular equilibrium zircon reference AS3 (230Th)/(238U)= 1.027 ± 0.005 (MSWD = 0.63; n= 34).U concentration from measured 238UO+/90Zr2O4+ relative to 91500 zircon with 81.2 ppm U.