This video shows an impressive explosion using 100 tons of explosives:
Here's another example:
This kind of "linear explosion", where one explosion ripples to the next in a line, is common in mining, farming and road building. There are several ways to do it, but one of the more common is called "ditching dynamite".
Ditching dynamite is a special formulation of dynamite that makes it more sensitive to shock. Therefore, if you put sticks of ditching dynamite along a line and detonate the first one, the shock of the explosion will detonate the next stick in the string. This article describes it like this:
Ditching dynamite (DD).1 This is a high explosive containing 50 percent nitroglycerine in an absorbing medium. Manufactured especially for ditch blasting, DD is highly shock-sensitive and water-resistant, enabling it to be fired by propagation in moist or wet soil. It is expensive and somewhat hazardous to handle on account of its sensitivity.
The other way to do it is to put a blasting cap in each hole and use a non-sensitive formulation like ammonium nitrate. Then a controller sends signals to each blasting cap in sequence. For a nice explanation, see this video:
For more information on the first explosion, see: Explosives Aid Wetland Restoration in Upper Klamath Basin
For a good technical description of ditch blasting, see: Ditch blasting
For an explanation of why you might want to have professional do your blasting rather than trying it yourself, see: Blasting in Texas