Seismic hazard in Buenos Aires, Argentina: A preliminary study on the effects of long‐distance earthquakes on tall buildings

Abstract

Summary The 2015 Illapel earthquake produced self‐evacuation of tall buildings in the city of Buenos Aires, Argentina, located 1280 km away from the epicenter. The ground motions in Buenos Aires due to the main event (Mw 8.3) and its aftershocks were registered by a new seismometer. The data collected allowed to estimate the maximum story drift ratios and top floor accelerations for tall buildings in Buenos Aires. The similarities between the response spectra and the Fourier amplitude spectra for the mainshock and its aftershocks show the influence that the dynamic properties of the 300‐m soil deposit have on the large acceleration amplification produced in these groups of buildings.

NDSHA - The New Paradigm for RSHA - An Updated Review

“…As further noted in Bertero et al (2018), regarding these distantly generated long period effects in Buenos Aires -where firm soil is found in the upper layers: site "amplification" resulting from polarization of seismic wave motion in the horizontal plane is produced because of the large depth of soil deposits.…”

“…As shown in Fig. 3 from Bertero et al (2018), tall buildings in Buenos Aires (1280 km away from the epicenter), although a great distance away from the 2015 Mw 8.3 Illapel, Chile earthquake, experienced horizontal acceleration time-series of motion that were significantly higher than the "motion perception threshold" limit for wind-induced vibrations as specified in ISO 10137 ( 2007) for human comfort, productivity and well-beingbecause motions at frequencies less than 1 Hz can provoke fear, discomfort and symptoms of motion sickness in buildings occupants.…”

“…Figure 3. Vertical and East-West (EW) Motions (North-South component is not available) in Buenos Aires (1280 km away from the epicenter) of acceleration (cm/s 2 ), velocity (cm/s), and displacement (cm) time series for the strong shaking portion of the Mw = 8.3 2015 Illapel, Chile earthquake: Sept 16, 2.015, at 22:54:32 UTC, originating 48 km offshore from Illapel, Chile (modified from Bertero et al, 2018) Although these low frequency motions induced by high winds will generally meet building strength and safety requirements, concerns have always been that they may nevertheless cause a wide range of adverse effects on building occupants, including: alarm or fear, discomfort, difficulty concentrating and symptoms of motion sickness (See e.g., "Human Exposure to Wind-Induced Motion in Tall Buildings: An Assessment of Guidance in ISO 68987 and ISO 10137", Howarth, 2015).…”

Ductility demands of tall buildings subjected to base rocking induced by Rayleigh waves

“…In a recent study of the elastic response of tall buildings to Rayleigh waves, we pointed the vulnerability of such long‐period structures to basin‐induced surface waves. Reinforcing evidence supporting such a conclusion (among other observations summarized in our previous study) may be found in Bertero et al (2018) who investigated the response of a number of tall buildings in Buenos Aires, Argentina, which were excited by the seismic motions (Rayleigh wave) generated by the M w 8.3 Illapel, Chile earthquake, 1280 km away.…”