A sizable earthquake struck the India-Myanmar border on Friday, seismologists said. There were no immediate reports of damage or casualties.

The 6.4-magnitude tremor rattled a remote region 50 miles east-southeast of the Indian town of Imphal in the state of Manipur, and 42 miles from Kolkata (formerly known as Calcutta), the U.S. Geological Survey reported Friday in a written statement.

The area, which is more than 250 miles from the Myanmar city of Mandalay, is home to few residents.

The USGS said the temblor hit at a depth of about 55 miles at 8:42 p.m. Indian Standard Time.

Democrats have been pushing the EPA to curb levels of perchlorate, a chemical used in fireworks and explosives, for years. The Bush administration opted to loosen restrictions on the rocket fuel components in 2008, exposing an estimated 16.6 million Americans to unsafe levels in tap water, AP reports.

Environmental Protection Agency administrator Lisa Jackson announced Wednesday that the Obama administration plans to enact a new standard for the chemical that could take up to two years to develop.

“As improved standards are developed and put in place, clean water technology innovators have an opportunity to create cutting edge solutions that will strengthen health protections and spark economic growth,” Jackson said in a statement.

Perchlorate usually taints water supplies when it is improperly disposed of at rocket testing sites, military bases and chemical plants. If the  proposed standard goes into effect, the military could face liability down the line for water contamination during rocket and missile testing, AP said.

Jackson will most likely face GOP opposition over the perchlorate standard when she testifies Wednesday before a Senate panel about new EPA regulations of air pollutants, including greenhouse gas emissions. Republicans hope to introduce new legislation that would strip the EPA of its power to regulate industrial emissions.

Democrats, including California Senator Barbara Boxer, lauded the EPA’s announcement. Boxer said she was thrilled the government was “finally going to protect our families from perchlorate.”

“I will do everything I can to make sure this new protection moves forward,” Boxer said, according to AP.

Environmental groups, including the Natural Resources Defense Council, also applauded the decision. Mae Wu of the NRDC writes that EPA monitoring found that 4 percent of public water supplies, providing drinking water to 17.6 million people, contained perchlorate at or above 4 parts per billion. She says contamination is present in almost every state.

Shinmoedake, a 4,662-foot peak in the Kirishima range on the southern Japan island of Kyushu, erupted last Thursday after 52 years of dormancy. Smoke plumes rose over 6,500 feet, and local residents were evacuated as a precaution. No injuries were reported.

On Monday, the volcano was still expelling a magnificent ash-cloud, coating local vegetable farms and disrupting airline flights, Reuters reports.

Authorities issued an evacuation advisory a 11:50 p.m. on Sunday (1450 GMT). About 1,100 residents in the town of Takaharu fled to evacuation centers, although many chose to remain in their homes.

According to The Associated Press, experts said a dome of lava was swelling inside the volcano. It is still unclear whether the dome will grow enough to spill over the crest and send searing lava down the mountainsides.

It has been nearly 300 years since Shinmoedake has been this active, Reuters reported Monday.

The massive power station will be constructed in Yambol, a city in the southeastern region on the Tundzha river, and will cost over 100 billion yen ($1.2 billion).

The project, slated for a March 2012 completion date, comes as the Eastern European nation scrambles to meet uncompromising European Union carbon emissions cuts. The new regulations aim to slash 1990 levels by 20 percent by the year 2020.

Bulgaria currently draws seven percent of its nationwide power from renewable energy sources. With the addition of the ambitious solar station, it hopes to increase that number to 16 percent.

The plant will reportedly generate about 50,000 kilowatts to start. That output capacity will be upped to 250,000 kilowatts in five years.

Toshiba and Tokyo Electric will team up with Japanese trader Itochu and the government backed Innovation Network Corp. of Japan to set up a local joint venture worth about 50 billion yen, AFP reports.

About 20 billion yen in the joint venture will come from CEZ Group, the seventh-ranked European energy company.

AFP reports that Japanese Economy and Industry Minister Banri Kaieda and Bulgarian Economy and Energy Minister Traycho will agree to back the venture at a meeting early next week.

On Wednesday workers began installing the first of the 6,400 panels, which the zoo says will make up the largest urban solar array accessible to the public in the U.S.

“It’s literally four acres of solar panels,” said Mark Fisher, the zoo’s senior director of facilities, planning and sustainability, according to the Cincinnati Enquirer.

The $11 million project was developed by green energy company Melink Corp., based in nearby Clermont County. Melink will also own and operate the 1.56-megawatt system.

The solar power installation will provide about 20 percent of the park’s electricity, or about $150,000 worth of annual utility costs.

Zoo visitors will get a chance to learn more about the solar array through an interactive kiosk, which will explain how the system works and how much energy is being produced.

The Cincinnati Zoo claims to be “the greenest zoo in America.”

Scientists at the Italian Institute of Vulcanology said the rumbles began Tuesday night and culminated Wednesday morning, when lava spilled down the mountain’s eastern rim. No one was injured.

The volcano emitted ash, obscuring the skies above Catania and forcing the overnight closure of Fontanarossa airport, The Associated Press reported.

The airport was reopened early Thursday. The volcano was only exhibiting weak activity by that time.

Etna is one of the world’s most active volcanoes. Its last major eruption was in 1992.

The 4.5-magnitude tremor struck Monterey County at 12:51 a.m., with an epicenter 6 miles south-southeast of San Juan Bautista and 45 miles southeast of San Jose.

A series of light aftershocks, including a 3.4 temblor, rattled the region in the early morning hours afterward.

There were no reports of damage or injuries. The quake was not even strong enough to shake books from shelves, the Los Angeles Times reported.

The “Buy American” provision may add to the list of growing tensions with China, which is the world’s largest exporter of green energy materials.

U.S. leaders believe that China unfairly subsidizes its clean energy sector, taking business away from the American solar and wind industries. The Obama administation has ordered an investigation into the matter and brought the issue before the World Trade Organization on Dec. 22.

The solar panel provision passed the House and Senate during the tail-end of the lame-duck session of Congress before the holiday break, and was carefully written to agree with WTO rules so that China will have less of a chance of getting it overturned, the New York Times reports.

The measure also imposes a Buy American mandate on other green technologies such as “energy savings performance contracts, utility service contracts, land leases, and private housing contracts.”

Despite China’s criticism of such stipulations in the past, the nation required in the spring of 2009 that the entirety of its $600 billion economic stimulus be spent within China.

The new rule comes as Chinese President Hu Jintao prepares for a visit to the U.S. next week.

The federal government announced Friday morning that fluoride, the substance credited with dramatically lowering cavity rates when added to water supplies, is causing tooth streaks and spots in 2 out of 5 adolescents.

The U.S. Department of Health and Human Services and the U.S. Environmental Protection Agencies are proposing to reduce the amount of fluoride in drinking water to a maximum of 0.7 milligrams per liter (mg/L), down from the previous limit of 1.2 mg/L, NPR reported Friday.

HHS says that most U.S. cases of the tooth-spotting condition, called dental fluorosis, has only a mild cosmetic effect and generally goes unnoticed by everyone besides dentists. But the agency says kids today are getting too much fluoride from drinking water, toothpaste and mouthwash, so the levels in the water supply will be scaled back.

Despite concerns raised by environmentalists regarding the possibility of groundwater pollution, the Texas Low-Level Radioactive Commission voted 5-2 to pass the measure, which will permit a number of additional states to export nuclear waste to an Andrews County dump owned by Waste Control Specialists. The site previously only accepted waste from Texas, Vermont and the federal government.

The commission also guaranteed Vermont preferred space of 20 percent capacity. Vermont has only one nuclear facility, which it plans to phase out in the next 30 or 40 years.

President Barack Obama has extolled nuclear energy as a clean alternative to oil, but opponents object to the radioactive waste associated with the process.

The proposal drew more than 5,000 public comments, The Associated Press reported.