Few monogenetic eruptions that produced lava flows have occurred in historical times, limiting the observations of their impact on human settlements. However, rheological models based on morphological and petrological datasets can contribute to decipher the eruptive dynamics and durations of ancient eruptions. The Malpais de Zacapu, a temporal-spatial monogenetic volcano cluster at the western margin of the Zacapu lacustrine basin (Michoacan, Mexico), offers a good opportunity to apply such models because of the availability of a high-resolution LiDAR topography from which detailed morphological data was extracted. The Malpais de Zacapu comprises late Holocene lava flow fields emplaced in the last 3200 years by four different low magnitude volcanic eruptions: Infiernillo, Malpais Las Viboras, Capaxtiro, and Malpais Prieto. Jointly these eruptions produced thick andesitic block lava flows covering an area of 38.3 km(2) with a volume of similar to 4.4 km(3). The lava viscosities at eruption vents were estimated from petro-textural analyses and range between 10(3) and 10(6) Pa s, while the final flow apparent viscosities, obtained from dimensional analyses, vary from 10(8) to 10(10) Pa s. We estimated the mean effusion rate and lava flow emplacement duration for each flow field. Results revealed that the more viscous flows, Malpais Las Viboras and Malpais Prieto, could have been emplaced in less than 3 years, while the more fluid Infiernillo probably took less than 1 year. In stark contrast, the morphologically different and more voluminous Capaxtiro flow field could have been emplaced in similar to 27 years. These findings can help to evaluate the impact that these eruptions had on adjacent pre-Hispanic populations, known to have inhabited the region since at least 3000 years ago.
Plan de classement
Géologie et formations superficielles [064]
;
Géophysique interne [066]
;
Sociétés, développement culturel [112]
;
Télédétection [126]
