Page 189 - Caldera Volcanism Analysis, Modelling and Response

164 Gerardo J. Aguirre-Dı ´az et al.

Figure 13 Digital elevation models of the Malpaso graben caldera and surrounding area. (a)
Malpaso graben caldera (MG) is bordered by two larger graben, Aguascalientes graben to the
east (Ags. Graben), and Calvillo graben to the west, farther to the west is theTabasco graben,
which is the northern continuation of the Juchipila graben. Inset shows the area covered in
Figure13b. (b) Malpaso graben caldera shown in more detail. It is a rhombohedral-shape struc-
ture oriented NE.Two main fault scarps mark the limits of the graben caldera, to the northwest
is the Mesa Montoro (MM) fault scarp, and to the southeast is the Sierra El Laurel (SEL) fault
scarp.The type section of the El Ocote ignimbrite is at the internal graben caldera scarp near
El Ocote village (EO). A, Aguascalientes City; C, Calvillo City.Thin lines in images are nor-
mal faults.