Are us approaches to forest management sustainable? are they maintaining ecological integrity?

are you referring to matrix mathematics!

true. earthquakes are felt whenever there is a slip around a fault in the rocks below the earth. this reorientation of faults create sesmic waves and is known as earthquake, the severity of which is measured in richter scale. these are more prominent in hilly regions as the rocks usually form faults to balance the pressures on it.

the value of the 4 in the hundreds place is 400 while the value of th e 4 in the tens place is 40

400 is way bigger than 40.