Intraslab versus interplate earthquakes as recorded in Mexico City; implications for seismic hazard
Intraslab versus interplate earthquakes as recorded in Mexico City; implications for seismic hazard
Earthquake Spectra (May 2015) 31 (2): 795-812
- acceleration
- accelerograms
- attenuation
- body waves
- buildings
- Cocos Plate
- earthquakes
- elastic waves
- elasticity
- engineering properties
- Federal District Mexico
- focus
- Fourier analysis
- frequency
- geologic hazards
- ground motion
- guided waves
- igneous rocks
- lacustrine environment
- lake sediments
- lakes
- lava flows
- Mexico
- Mexico City earthquake 1985
- Mexico City Mexico
- Mexico state
- natural hazards
- North American Plate
- plate tectonics
- pyroclastics
- recurrence interval
- risk assessment
- S-waves
- sediments
- seismic waves
- seismicity
- slabs
- soils
- spectral analysis
- subduction
- surface waves
- Trans-Mexican volcanic belt
- tuff
- volcanic rocks
- wave amplification
- Zumpango earthquake 2011
We study the relative importance of interplate and intraslab earthquakes in the seismic hazard of Mexico City by analyzing accelerograms recorded at the hill-zone site of CU (1964-2012) and the lake-bed site of SCT (1985-2012). A (sub max) exceeded 6 gal during 20 earthquakes at CU during this period. Of these, eight were intraslab events so that the exceedance rate of A (sub max) > or = 6 gal from both types of earthquakes is roughly about the same. The estimated return period of A (sub max) of 30 gal from the two types of earthquakes is approximately 100 yrs. If we consider high-frequency (2.5-8.5 Hz) acceleration (A (sub max) HF) at CU, then the top 7 out of the 20 events are all intraslab earthquakes. Even at the lake-bed site of SCT, the A (sub max) HF values are, generally, associated with intraslab earthquakes. It follows that the risk from both types of earthquakes to low-rise construction in the city needs careful assessment.
