Interior to this 4:1 resonance, asteroids in low inclination orbits are, unlike those outside the 4:1 Kirkwood gap, strongly influenced by the gravitational field of Mars. Here, instead of Jupiter's influence, perturbations by Mars have, over the lifetime of the Solar System, thrown out all asteroids interior to the 4:1 Kirkwood gap except for those far enough from Mars's orbital plane where that planet exerts much smaller forces.
Located within a 4:1 resonance, asteroids in low inclination orbits are, unlike those outside the 4:1 Kirkwood gap, significantly influenced by Mars's gravitational field. In contrast to Jupiter's influence, perturbations caused by Mars have, over the lifetime of the Solar System, expelled all asteroids interior to the 4:1 Kirkwood gap except for those far enough from Mars's orbital plane where its forces are much smaller.