1 For subsidence caused by sudden collapse of the ground to form sinkholes, several measures can be taken. 2  First, geologists can make maps of areas known to be underlain by rocks like limestone, gypsum, or salt, that are susceptible to dissolution by fluids.
The Navajos used bows and arrows, spears, clubs, tomahawks, knives and sticks among their tools and weapons. Beyond these, they also used bolas and... The Navajos used bows and arrows, spears, clubs, tomahawks, knives and sticks among their tools and weapons. Beyond these, they also used bolas and blowguns. The Navajos employed the use of several tools and weapons:Bows and arrows were used by Native Americans to defend themselves, and sometimes for fishing. They also used them for hunting animals like bison.When fighting against European explorers, Native Americans used spears.
Utah History Encyclopedia. The Navajo Indians in Utah reside on a reservation of more than 1,155,000 acres in the southeastern corner of the state. According to the 1990 census, more than half of the population of San Juan County is comprised of Navajo people, the majority of whom live south of the San Juan River.