WASHINGTON Wholesale Nike Air Max 90 Ultra SE , Aug. 2 (Xinhua) -- The destructive power released by human-induced and naturally occurring earthquakes in the central United States is actually "indistinguishable," a U.S. study said Wednesday.
The finding, published in the U.S. journal Science Advances, contradicted previous observations suggesting that induced earthquakes exhibit weaker shaking than natural ones.
Earthquakes in the central U.S. have increased over the past 10 years due to the expansion of unconventional oil and gas operations that discard wastewater by injecting it into the ground.
About three million people in Oklahoma and southern Kansas live with an increased risk of experiencing induced earthquakes.
A key question is whether these induced earthquakes excite ground motions that are substantially different than those of naturally occurring earthquakes.
To answer this question, the new study used available instrumental recordings to estimate the stress drop -- the difference between the stress across a fault before and after an earthquake -- of 39 moderate-magnitude induced and natural earthquakes in the central U.S and in eastern North America.
Once the faulting mechanism and the depth of the quakes are accounted for, the stress drops of induced and natural earthquakes in the central U.S. share the same characteristics, results showed.
"Our study shows that induced earthquakes and natural earthquakes in the central U.S. are inherently similar, and we can predict the damaging effects of induced earthquakes using the same framework as natural earthquakes," said first author Yihe Huang, an assistant professor at the University of Michigan.
The study also found that naturally occurring earthquakes in the eastern North America may lead to stronger shaking than natural earthquakes in the central United States.
That's because most eastern earthquakes occur on reverse faults, while most central U.S. induced and natural earthquakes occur on strike-slip faults. Reverse-faulting earthquakes typically have stronger shaking than strike-slip earthquakes.
The scientists said that the types of rocks being exploited by unconventional oil and gas recovery in the U.S. and Canada can be found all over the world, making the results of this study widely applicable.
"As we can learn better practices, we can help ensure that the hazards induced earthquakes pose can be reduced in other parts of the world as well," added co-author William Ellsworth, co-director of Stanford University's Center for Induced and Triggered Seismicity.
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Business > Employee Relations > Employee Assistance ProgramShould A Business Have A Good Employee Rewards System?
Posted by jennifertay in Business on December 3rd, 2017
In any organization the employees are the most significant asset an employer can have. Therefore, to keep them glued to the organization's goals, you have to keep them motivated. That is the reason the employer should have a good employee reward program - factor that comes to the mind of any management when developing an employee reward program, is the goal of the organization. Whether the organization is performing on a large or a small scale level, they will want the employees to be tuned to their vision. This is because they understand that as much as they are motivating their employees, it means that they have to incur more costs. Additionally, they understand that these rewards come in a different package from the salary, or the merit system.
These systems aim at giving the necessary rewards to employees based on two factors: their performance and their behavior. In terms of performance, they will recognize staff that will have done the necessary work to meet the firm's goals. For instance, when employees make commendable profits to the organization, then employers will give a small percentage from it. In terms of behavior, a staff member who comes to work early and leaves late, will be rewarded by the top management.
Before coming up with an employee reward program, the employers have to sit down and analyze several things. In terms of the goals, the employer should know whether they will form the system on the basis of individual or team accomplishments. They will state the department of their firm that they wish to include, and the desired behavior that they would want to see in that same department.
They should also consider how they will measure the reward. Such rewards include bonuses in their salary; profit sharing, in terms of commission; and stock options or equity ownership -where employees are free to own shares within the company.
At the end, if the appropriate employee reward program is in place, the organization should notice changes in the behavior of their employees, and an incredible move towards the goal and the vision of the firm.
Health > Physical HealthTechniques and Tips on How to Induce Them
Posted by sasi in Health on September 6th, 2016
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