2011/10/13 by Emile A. Okal, J. C. Borrero · 1 voice · 4 citations
Earth and Planetary Sciences · #Earthquake Detection and Analysis #High-pressure geophysics and materials #earthquake and tectonic studies
paper · pdf · doi:10.1111/j.1365-246x.2011.05199.x
openalex publication_date 2011/10/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
We conduct a detailed seismological study of the large Colima, Mexico earthquake of 1932 June 3 and of its aftershocks of June 18 and 22. The latter (Event III) generated a tsunami more devastating than that of the main shock despite much smaller seismic magnitudes, thus qualifying as a so-called ‘tsunami earthquake’. Relocation based on published arrival times shows that Event III took place up-dip of the main shock. The analysis of the spectral amplitude of mantle surface waves yields low-frequency moments of 24, 5.2 and 4 times 1027 dyn cm, respectively, with Event III featuring a moment growing with period, which expresses the source slowness characteristic of ‘tsunami earthquakes’. This is confirmed by a deficient energy-to-moment ratio, as derived from high-frequency P waves recorded at Pasadena. Near-field hydrodynamic simulations show that the effects of the main shock′s tsunami are well modelled by a standard seismic source, whereas the stronger tsunami from Event III can be modelled by rupture along a splay fault in a mechanically deficient material. All our results then fit the model for ‘tsunami earthquake’ aftershocks proposed for the Kuril Islands by Fukao in 1979.