[en] We studied the multielectron ionization and Coulomb explosion of O₂ irradiated by 110 fs, 810 nm laser pulses at an intensity of 10¹⁵ W cm^-2. Strong anisotropic angular distributions with the same widths were observed for the atomic ions Oⁿ⁺ (n = 1-3). Using two linearly polarized laser pulses with crossed polarization, we found that the atomic ions generated in the second laser pulse were strongly depleted by the first laser pulse for various delay times. The results demonstrate that dynamic alignment dominates for O₂ under the experimental conditions. Moreover, the same angular distributions for all the atomic ions Oⁿ⁺ (n = 1-3) further demonstrate that dynamic alignment mainly occurs at the rising edge of the laser pulse with laser intensity below the ionization threshold and the neutral O₂ aligns along the laser polarization vector prior to ionization