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.
The Navajo lived in places called hogan in English and hooghan in Navajo. They are described in the creation stories. One of the two center sacred mountains is supposed to be in the shape of one.he Navajo Nation is 27,000 square miles (the size  of Holland and Belgium combined) and ranges from 4,500 feet and  8,000 feet in elevation with even higher mountains, so t â¦ here is a  great deal of variation in climate.