Browsing by Author "Ramirez-Herrera, MT"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Extreme wave deposits on the Pacific Coast of Mexico: tsunamis or storms? - A multi-proxy approach
    (American Geophysical Union, 2011-12-05) Ramirez-Herrera, MT; Lagos, M; Hutchinson, I; Chagué-Goff, C; Kostoglodov, V; Goff, JR; Ruiz-Fernandez, A; Machain-Castillo, ML; Caballero, M; Goguitchaichrili, A; Aguilar, B; Urquijo, P
    Historical and instrumental data show that the Pacific coast of Mexico has been exposed to destructive tsunamis over at least the past 500 years. This coast is also affected by hurricanes generated in the eastern Pacific. The great 1985 Mexico earthquake and its aftershock generated tsunamis that affected the Ixtapa-Zihuatanejo and Michoacán coast. The purpose of our study was two-fold, a) to determine whether we could distinguish storm from tsunami deposits, and b) whether tsunami deposits from historical events are preserved in the tropical environments of the Ixtapa-Zihuatanejo coast. Two anomalous sand units in the Ixtapa estuary are interpreted as the result of high-energy marine inundation events that occurred in the last century. Several lines of evidence using a multi-proxy approach (historical studies, interviews with local witnesses, geomorphological and geological surveys, coring and trenching, and laboratory analyses including grain size, micropaleontology, geochemistry, magnetic susceptibility and radiometric dating) indicate the occurrence of two tsunamis that we link to local events: the 1985 Mexico and possibly the 1979 Petatlan earthquakes. We thereby provide the first onshore geological evidence of historical tsunamis on the Pacific coast of Mexico. © American Geophysical Union
  • No Thumbnail Available
    Item
    The geological trace of the 1932 tsunamis in the tropical Jalisco-Colima
    (American Geophysical Union, 2013-05-14) Ramirez-Herrera, MT; Blecher, L; Goff, JR; Corona, N; Chagué-Goff, C; Lagos, M; Hutchinson, I; Aguilar, B; Goguitchaichrili, A; Machain-Castillo, ML; Rangel, V; Zawadzki, A; Jacobsen, GE
    The study and preservation of tsunami deposits have being challenging in humid tropical environments. While tsunami deposits have been widely studied at temperate latitudes, few studies assess this problem in tropical environments due to the difficulties intrinsic to these places (e.g. tsunami deposit preservation, post-burial changes in a tropical environment, mangrove vegetation, difficult access, wildlife, among others). Here we assess the problem of tsunami-deposits preservation on the Jalisco-Colima tropical coast of Mexico, which parallels the more than 1000-km long Mexican subduction, where historical accounts indicate the occurrence of two significant tsunamis on June 3 and 22, 1932 (Corona and Ramírez-Herrera, 2012a, Valdivia et al., 2012). However, up to date, no geological evidence of these events has been reported. We present geological evidence of two large tsunamis related to the June 3, M 8.2 earthquake, and the June 22, Ms 6.9 landslide-triggering event of 1932 (Corona and Ramírez-Herrera, 2012a, b). A multiproxy approach was applied to unravel the nature of anomalous sand units and sharp basal contacts in the stratigraphy of a number of sites at Palo Verde estuary, El Tecuán swales and marsh, and La Manzanilla swales, on the Jalisco-Colima coast. Lines of evidence including historical, geomorphological, stratigraphic, grain size, organic matter content, microfossils (diatoms and foraminifera), geochemical content, magnetic susceptibility and AMS analyses, together with dating (210Pb and 14C), and modeling, corroborate the presence of tsunami deposits of both the 3 June 1932 tsunami at El Tecuán and La Manzanilla, and the 22 June 1932 tsunami at Palo Verde. Further evidence of earlier tsunamis, at least four events, is also evident in the stratigraphy. Work in progress should reveal the chronology of the earliest tsunamis and their origin. Corona, N., M.T. Ramirez-Herrera. (2012a) Mapping and historical reconstruction of the great Mexican 1932 tsunami. Natural Hazards and Earth System Sciences, 12, 1337-1352. NHESS-2011-369. Corona Morales N. y M.T. Ramírez-Herrera. (2012b) Técnicas histórico-etnográficas en la reconstrucción y caracterización de tsunamis: El ejemplo del gran tsunami del 22 de junio de 1932, en las costas del Pacífico Mexicano. Revista de Geografía Norte Grande. 53, 107-122. Valdivia O. L., Castillo A. M.R., Trejo E. M. (2012). Tsunamis en Jalisco, Geocalli, Cuadernos De Geografía, Universidad de Guadalajara. Año 13, No. 25, 103p.