Page 323 - Caldera Volcanism Analysis, Modelling and Response
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298 Valerio Acocella
Figure 9 Experiments with regional stress: Holohan et al., 2005. (A) Adopted apparatus;
section view of the caldera reverse ring faults with neutral (B), extensional (C) and compressional
(D) stress ¢eld (modi¢ed after Holohan et al., 2005).
Since these variations are observed only along a direction parallel to s3 (regional
extension) or s1 (regional compression), the overall result is the development of an
elliptic caldera, elongated parallel to s3 (during extension) or perpendicular to s1
(during compression). Its minimum eccentricity is B0.8.
