For any fixed positive integer $k$, let $α_{k}$ denote the smallest $α\in (0,1)$ such that the random graph sequence $\left\{G\left(n, n^{-α}\right)\right\}$ does not satisfy the zero-one law for the set $\mathcal{E}_{k}$ of all existential first order sentences that are of quantifier depth at most $k$. This paper finds upper and lower bounds on $α_{k}$, showing that as $k \rightarrow \infty$, we have $α_{k} = \left(k - 2 - t(k)\right)^{-1}$ for some function $t(k) = Θ(k^{-2})$. We also establish the precise value of $α_{k}$ when $k = 4$.