LA LAVINA DEL VALLE CENTRAL (COSTA RICA): ¿LAHAR O DEBRIS AVALANCHE?

The denominated lavina of the Central Valley, constituted by lava blocks floating in a volcanicmud matrix, had been interpreted genetically as a lahar or debris flow deposit. This work tries to discuss somecharacteristics that suggest that the deposit originated in a debris avalanche event, that tra...

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Bibliographic Details
Authors: Hidalgo, Paulo J., Alvarado, Guillermo E., Linkimer, Lepolt
Format: article
Status:Published version
Publication Date:2011
Country:Costa Rica
Institution:Universidad de Costa Rica
Repository:Portal de Revistas UCR
Language:Spanish
English
OAI Identifier:oai:portal.ucr.ac.cr:article/7261
Online Access:https://revistas.ucr.ac.cr/index.php/geologica/article/view/7261
Access Level:Open access
Keyword:lavina
valle central
lahar
debris avalanche
anfiteatros
morfometría
estratigrafía
central valley
amphitheater
morphometry
stratigraphy
Description
Summary:The denominated lavina of the Central Valley, constituted by lava blocks floating in a volcanicmud matrix, had been interpreted genetically as a lahar or debris flow deposit. This work tries to discuss somecharacteristics that suggest that the deposit originated in a debris avalanche event, that transformed into a debrisflow. Avalanche amphitheaters were identified in extinct stratovolcanoes in the western sector of the Irazú volcano, where the most probable source of origin is the sector of collapse in the west flank of the Cabeza de Vacavolcano. This event could have occurred around 150 ka -250 ka, possibly during or at the end of glacial periodsin the northern hemisphere. Wells in most of the Metropolitan area allowed the morphometric definition of thestratigraphic surfaces, and determined a volume = 2.0 km3 in an approximated area of 130 km2.