What Causes Sinkholes?


This week saw record rain as Mother Nature unleashed her wrath on area residents. The heavy rain not only caused flooding, resulting in widespread street closures and traffic jams, but it also swept away asphalt’s base material (gravel and sand) as drivers have surely noticed. This ultimately promoted the weakening of many Arizona roadways, causing depressions, cracks and potholes to occur.

Heavy rains also caused the ground to suddenly open, without any warning, in two valley locations this week. These holes in the ground are sinkholes. Talk about a scary October! However, many people don’t know what causes them or whether they can be fixed and if they can, how. Continue reading to learn what causes these giant holes in the ground and how they can be properly repaired to prevent recurrence.

What Causes Sinkholes?

Sinkholes occur in areas known as “karst.” Karst describes a distinctive topography that indicates dissolution of underlying soluble rocks by groundwater or rainwater. Soluble rocks include limestone, dolomite, gypsum, and rock salt. When rainwater seeps downward, usually through existing cracks and potholes, the water eats away at the rock. It’s then possible for underground caverns to form. Over time, these caverns can continue to grow and extend towards the surface, producing sinkholes.

How to Properly Fix Them

Sinkholes can be fixed! There are two goals for repairing sinkholes: Stabilizing the area and preventing them from developing again. A thorough evaluation of the hole’s location and size are required to choose the best repair method. Deep sinkholes usually demand a wide variety of heavy machinery and materials. Popular materials for filling these sinkholes include concrete and crushed stone. Once the site is filled, new asphalt can be laid down and the road reopened for travel.

L&L Asphalt is a woman-owned asphalt and repair services company. We have been awarded many projects by general contractors and municipalities. Our services include permanent asphalt replacement, street widening, and asphalt overlays.

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