The largest, deep earthquake ever recorded, struck on May 24, 2013, beneath the Sea of Okhotsk, between the Kamchatka Peninsula and Russian mainland. The earthquake occurred at a depth of 609 kilometers with a magnitude-8.3. Though here was no damage from the quake, but the effects were felt on the surface as far as the Middle East.
Deep earthquakes are exceedingly common. They most often occur in association with deep ocean trenches and volcanic island arcs in subduction zones. The body waves of deep earthquakes are used by seismologists more often than those of shallow earthquakes to investigate core, mantle and crustal structure. This is for the reason that deep earthquakes possess relatively more impulsive sources.
These deep earthquakes occur in the older and colder areas of oceanic plate that gets pushed into the earth’s mantle. It has been supposed that the earthquakes are caused when a mineral common in the upper mantle, olivine, undergoes a transformation that weakens the whole rock temporarily, causing it to fail.
Deep earthquakes are not felt at Earth’s surface in the same way as shallow quakes. These are felt in the skyscrapers as a swaying motion resulting from the low-frequency waves. On the other hand, shallow earthquakes are felt as sharp jolts on the surface. Deep earthquakes occur in the transition zone between the upper and lower mantle at depths between 400 and 700 kilometers, only at those subduction zones where cold material is forced down the mantle very quickly.
While studying about the consequences of the deep earthquake that occurred beneath the Sea of Okhotsk, the scientists suggested that deep earthquakes may be better at dissipating pent-up energy than similar earthquakes near the surface. The initial earthquake triggered four other powerful shocks. The entire sequence of earthquakes happened in just 30 seconds, with most of the energy released by the four major shocks. Contrary to this, similar earthquake swarms that occur near the surface can take hours or days to finish. So it is clear that deep earthquakes are likely more efficient in dissipating stress than are shallow ones.
I have always been fond of peeping inside the well. I still remember the time few years back when I followed my mother going to the well to draw water. All this seemed very amusing to me. But she no more goes to the well. When I asked her the reason, she told me that the water of the well is not clean enough for us to drink or use. I could not reason out the cause of this. How had the water of the well become septic?
While trying to figure out the reason, I came across a term that was possibly the answer to my question – Hydraulic Fracturing. The practice is also known as fracking and has been one of the talked-about resource recovery methods in the country. It’s an economical method to recover natural gas from dense shale formations.
The fluid that returns to the surface because of the internal pressure of the rock formation contains injected chemicals and natural materials like metals and hydrocarbons.
Let us take a look at some of the facts and results of hydraulic fracturing:
- It takes 1-8 million gallons of water to complete each fracturing job. This water is mixed with sand and chemicals to create fracking fluid Approximately 40,000 gallons of chemicals are used per fracturing.
- About 600 chemicals are used in fracking fluid that includes carcinogens and toxins such as lead, uranium, mercury, methanol, hydrochloric acid, formaldehyde and many more.
- During the process, methane gas and toxic chemicals leach out from the system and contaminate nearby groundwater. Methane concentrations are 17 times higher in drinking-water wells near fracturing sites than in normal wells.
- This contaminated water is used for drinking for nearby cities and towns. There have been more than 1,000 documented cases of water contamination next to areas of gas drilling as well as sensory, respiratory, and neurological damage due to ingested contaminated water.
There are many other harmful results of fracking that will not only affect us but also the nature. Fracking needs to be controlled to a great extent. There is need for the governments to come together against this practice. Serious steps need to be taken before it’s too late.
The devastation caused by natural disasters is not just limited to property and infrastructure but also to human life. Often, there is a huge loss of human lives in a disaster. When research and rescue teams from agencies like Federal Emergency Management Agency (FEMA) go into areas after an earthquake or a tsunami, they have limited resources to cover large areas.
This led to the discovery of a new tool from NASA and the U.S. Department of Homeland Security to help emergency responders locate victims following major disasters known as the Finding Individuals for Disaster and Emergency Response (FINDER). It is a lightweight, portable radio wave detector that helps the emergency responders to search for victims.
Let us take a look at some of the advantages the new heartbeat detector may offer emergency responders during a disaster.
- It can quickly identify people who are alive and trapped in debris. Often, victims are trapped and injured and die because of lack of oxygen. Locating them quickly can help in saving their lives.
- FINDER is portable, weighs only 9 kilograms and runs on batteries. These features make the device easily transportable to areas in greatest need.
- The detector uses lithium batteries that last for about 12 to 14 hours, which is the length of the shift of an emergency responder.
According to NASA’s Jet Propulsion Lab, the latest version of the device has the capacity to detect a heartbeat from 100 feet away in open space and up to 30 feet of crushed material and 20 feet of solid concrete. The technology can discriminate between a human and an animal. The microwave radar technology is sensitive enough to distinguish a human heartbeat from that of other living creatures.
For now, emergency responders use other devices, video camera and dogs in their rescue missions. FINDER could be ready for commercial use by the middle of 2014.
While strolling down the street last evening, I noticed a child playing. Trying to keep up with other kids, he ran out of breathe and fell. Startled, I dashed and picked him up, attempting to figure out what really had happened.
There was dizziness in his eyes. He was weak, very weak indeed. I looked at him and hopefully found the cause. The kid appeared to be suffering from lead poisoning. I knew it because I had seen some other cases too in the sphere suffering from the same condition.
What I know about lead is that it’s a very strong poison which once swallowed can lead to serious health problems. On reading more about it, I found that it sometimes causes fatal conditions too and is especially harmful to the neurological development of children.
Children are exposed to lead when they put lead objects in their mouth or touch a dusty or peeling lead object. But, lead-based paint and lead-contaminated dust in older buildings are the most common sources of lead poisoning in children. Contaminated air, water and soil are some of the other sources.
Human activities like mining, manufacturing and usage of leaded gasoline lead to lead poisoning. People who work as welders, potters and metal smelters, are at a greater risk of the condition. Even tap water can be contaminated with lead if the water pipes are made of this metal.
Lead poisoning can damage the nervous and reproductive system of the body and can cause high blood pressure and anemia. The condition can also result in severe mental and physical disorders in small children. In adults, it can cause nerve damage to the sense organs and nerves controlling the body. The condition can also lead to hearing and vision impairment and increased blood pressure.
If you care for your child and yourself, there is a lot you can do to reduce exposure to lead. Try to keep your home as dust-free as possible. Throw out old painted toys if you don’t know whether the paint contains lead. Wait for a minute and let the tap water run before drinking or cooking with it. Don’t forge, a healthy family is a happy family.
For the first time, researchers have shown that stomachs are equipped with nerves that are sensitive to stretching in a way that they act as a clock that limits eating to specific times of the day. These nerves allow higher food intake during waking hours, when more energy is needed.
The researchers used the 8-week-old female mice and studied variations in relevant gene expression every three hours over a 24-hour period. The changes were recorded in mechanoreceptors of nerves that respond to stretching of the stomach. The response of the receptor was independent of the food intake or even artificially modified light-dark cycle
A report in The Journal of Neuroscience stated that a gastric clock affects how easily and quickly mice feel satisfied when they eat and is dependent on the time of the day. Stephen Kentish, a researcher at the University of Adelaide’s Nerve-Gut Research Laboratory explained that these nerves are responsible for letting the brain know how much food we have eaten and when to stop. He also stated that the nerves in the gut are least sensitive at time periods associated with being awake. This means more food can be consumed before we feel full at times of high activity, when more energy is required.
However, the nerves in the stomach become more sensitive to stretch with a change in the day-night cycle to a period associated with sleeping. They signal fullness to the brain quicker thus limiting food intake. This variation repeats every 24 hours where the nerves act as a clock to coordinate food intake with energy requirements.
Study leader, Amanda Page, noted that the finding relates to people’s daily routine and the importance of abiding by the body’s digestive variations. She stated that the shift workers are more prone to disruptions in sleep and eating behavior that lead to obesity and other health problems.