Model of Soil Deposits - part 1 | part 2 | part 3
Geology of the Managua area
Managua city lies in a relatively plane surface that inclines smoothly toward Lake Xolotlán; inclination interrupted in several places by hills, most of them of volcanic origin.
Underlying the area is a breach of volcanic tuff that belongs to the upper part of the Las Sierras Group. Pyroclastic materials from the Holocene volcanism, a sequence that consists of lapilli, pumice, ashes, tuffs, etc., cover the former. Soils are classified mainly as non-cohesive silts, sands and gravels, which are poor to well consolidated and with different compaction degrees, presenting usually low densities and high porosity.
These materials are present in very well defined layers with thickness and degree of compaction that vary among sites even near to each other. Those variations in the soils distribution hinder to establish regular patterns in the soil profiles.
Nevertheless, from the point of view of the Seismic Engineering, the soils of Managua can be considered as relatively homogeneous [Johansson, 1988], and its dynamic behaviour has been in general good during seismic events [Faccioli et al.,1973], in the sense that there did not occur any great geologic effects.
