The seismic wave that causes the ground to move in two directions is the Love wave.

Here's why:

* Love waves are surface waves that travel along the Earth's surface.

* They have a horizontal motion, meaning they shake the ground back and forth perpendicular to the direction the wave is traveling. This is in contrast to Rayleigh waves, which move in a rolling, elliptical motion.

Let me know if you'd like to know more about other types of seismic waves!