Why did the western front barely move throughout world war 1?

In the western front, they used Trench Warfare Method 

In Trench Warfare the opposing teams would build some sort of trench surrounding their defended area to prevent the the opposing team in invading their protected Area. It's best used as a Defensive method which require the armies to stay hold and defended their position. That's why they're not moving so much 

Humid continental climate is found in the interior of continents between the 30 and 60 degrees latitude, but usually above the 40 degree line.   40 degrees north of the equator means less direct sunlight and therefore less warmth.   this climate is mainly found in the northern hemisphere since there are no major landmasses in the southern hemisphere.  if you live in northern indiana, you know all about humid continental because that is the climate type you have!

Answerstratovolcanoes///near or in the ring of fire;