A massive wave built and loomed in the air above Joel. Unaware of Anna's powers, he didn't see the point of the attack; surely the previous one had proven that he was too heavy and steady to be knocked down or carried away by a comparatively small quantity of water. To ensure his stability, Joel deliberately buried his legs knee-deep in the sand, then let the apparently harmless water crash over him and wash back into the sea. 

From Joel's point of view, that large wave had an additional benefit - it had drenched the sand where he stood, turning dry, loosely packed grains into firm, wet sand. Now that he had to use less of his geokinesis to prevent himself from sinking, he could focus more power on preparing his first attack. He could also construct sturdier structures out of packed, wet sand, should he need to later on.

The smaller rocks and pebbles had reached the edge of the forest. With a thought, Joel sent them flying at Anna in a rapid barrage. Pellets of varying sizes came from the forest in multiple directions, converging on Anna's location. Typical ranged missiles slowed down throughout their trajectories as they encountered air resistance. Joel's pebbles, however, gained speed as they flew, since he used the force of his power to continually accelerate them. Most projectiles also continued in a straight line after they were hurled, but Joel could alter the directions of his missiles up until they were near the very edge of his 200 meter range. Unfortunately, he didn't have fine control by that point, so he planned to change their trajectories slightly earlier. He kept them flying in straight lines for the moment, not yet demonstrating the true extent of his control. If Anna tried to dodge or block, however, Joel was prepared to make them rapidly circle around obstacles and target her new location. He was aware that most of the rocks and pebbles would probably miss, but there were a lot of them, and each hit would be enough to cause pain and bruising.