feels earth magic

Mab had just wheeled in preparation to charge again when there was a deep, ugly note in the air, almost below the range of my hearing, the kind of sound that you hear during disaster movies that have a lot of buildings collapsing, and maybe during earthquakes.
At the same time, my wizard’s senses were assaulted by a serious, heavy-duty pulse of earth magic.
There wasn’t even time to shout a warning. I called upon the Winter mantle for strength and speed and dove at Mab. The unicorn whirled to try to keep her away from me at the last second but wasn’t quite quick enough, and its movement was impeded by several abomination statues.
I was airborne when I saw the attack coming—jagged spears of metal, made from what looked like rebar scavenged from the wreckage of demolished buildings.
There wasn’t one spear.
There weren’t a dozen.
There were hundreds.
If the Winter unicorn had not reared to protect Mab, I figure I’d have died right there. Instead, the creature’s body intercepted maybe a dozen of the spears. I had leapt so that my back and the spell-armored duster that covered it would be between the spears and the Winter Queen.
I hit Mab and carried her off the back of the doomed unicorn.

Battle Ground Chapter 27, Page 253-254