Final answer:
The source, a personal interview with a rancher, is not credible due to bias and lack of expertise.
Step-by-step explanation:
The source provided, a personal interview with Bill Richardson, is not credible. Credibility is determined by the reliability, expertise, and bias of the source.
In this case, Bill Richardson is a rancher with a vested interest in the oil and gas industry and holds a biased view that the earthquakes are not caused by man-made activities related to drilling and fracking.
It is important to consider information from reliable and unbiased sources such as scientific studies and expert opinions from geologists and seismologists to accurately understand the causes of earthquakes.