『Abstract
　In the Aztec period and in colonial times different natural stones originating in the Valley of Mexico were used for building construction. Stone weathering was investigated onsite at various historical buildings within the older quarter of Mexico City. In this study, different aspects of weathering and deterioration at three significant historical buildings will be presented, the Aztec excavation site Templo Mayor, the Metroplitan Cathedral, and the colonial palace of the dukes of Heras Soto. Petrophysical properties of the main building stones of these structures were investigated like density, porosity, pore radii distribution, water uptake rate and coefficient, thermal and hygric expansion, and the mechanical properties of uniaxial compressive strength. A relationship between single critical property values, according to anisotropy fabric chracteristics, and specific weathering forms could be deduced.

Keywords: Stone weathering; Mexico-DF; Petrophysical properties; Isotropy-anisotropy; Critical values』

Introduction
Methods
Mapping and in situ investigations of the buildings
　The Templo Mayor
　Palace of the dukes of Heras Soto
　The Metropolitan Cathedral
Rock fabrics and petrophysical properties
　Tezontle basalt
　Tenayocatetl（後のaの頭に´） rhyolitic ignimbrite
　Remedios tuff (Gris de los Remedios)
　Chiluca: fresh and altered (Cathedral)
Discussion
　Sample I
　Sample II
　Sample III
　Sample IV, V
Conclusion and prospects
Acknowledgments
Open Access
References