<?php

$arr1=array(array(12, 8, 5, 34),
        array(54, 87, 32, 10),
        array(23, 76, 98, 13),
        array(53, 16, 24, 19));

$sortKey = 1;
array_multisort(array_map(function($v) use($sortKey){
	return $v[$sortKey];
}, $arr1), $arr1);

print_r($arr1);