Chile

Photos: Volcanic eruption in Chile

The Puyehue volcano in the Andes Mountains in southern Chile is erupting. The Boston Globe has a set of 32 pictures showing the eruption and people dealing with the ash fall. The ash plume at the volcanic is six miles high and one mile wide.

See the photos here.

H/T to Syver More for bringing these to my attention.

Biofuel from Prickly Pear Cactus

Universidad Mayor in Santiago, Chile is experimenting with the use of plantation-grown prickly pear cactus for use as biofuel. They intend to establish plantations in the Atacama desert, a place that averages 0.004 inches of rain a year, mainly as fog from the Pacific Ocean.

Reporter Anatoly Kurmanaev of the Santiago Times sets the scene:

The driest place on earth, the Atacama Desert in northern Chile, wouldn’t seem an auspicious place for biofuel production.

Biotechnology experts, however, may have found a way to turn one of the desert’s only available plants, the cactus, into energy.

A US$500,000 pilot project in the Río Jorquera Valley in the Copiapó province aims to reduce Nopal cactus stems to high-energy dry briquettes that can be burned in coal-fired thermoelectric plants.

The five-acre experimental plantation will produce sufficient scientific data on cactus biomass production in arid conditions by the end of 2013, and will then begin supplying fuel to a small-scale onsite power station.

The project’s leader, Prof. Alexis Vega of Universidad Mayor’s Biotechnology Institute in Santiago, believes a pilot-scale plantation of 420 acres will be able to sustain 1.5 megawatts per hour (MW/h) of electricity generation.

At an estimated cost of US$112 per MW/h, cactus biofuel is competitive with fossil fuels at current global prices and is much cheaper than other sources of alternative energy in the region such as wind or solar.

“This is an opportunity to diversify the local economy by utilizing marginal soil—land which has little water and few agricultural alternatives,” said Vega.

The researchers hope to develop the plantation to a level where they can begin supplying large electrical utilities in northern Chile.

One of the advantages of the cactus plantations is their proximity to energy-hungry mining operations. Utilizing locally available sources of energy would reduce the need for costly energy shipments from the south, Vega explained.

“Four years ago, when we approached the big power distributors they told us no. Now the moment has arrived—they are keen to participate.”

A law passed in 2010 binds Chile to generate 10 percent of its electricity from renewable, non-conventional sources by 2024.

At present the figure stands at around five percent, and Vega believes the government’s support for alternative energy puts the nation well on course to meeting the target.

Apart from the environmental benefits, researchers believe the scheme also holds substantial economic potential.

Southern Atacama’s traditional crop has been the table grape, the profitability of which has fallen steadily in recent years due to growing competition from Peru and Argentina.

As cactuses require at most a third of the water used by a grape plantation of the same area, there are large potential savings for farmers, as well as stable year-round jobs.

“For the small declining indigenous communities of northern Chile this is a real development opportunity,” said Vega. “These people can stay on the land, produce fuel for their own use, and sell the surplus, instead of migrating to the cities where they will remain poor.”

According to a report from Universidad Mayor, the cactus can be used in two ways: 1) anaerobic bio-digestion can produce methane for use as a feedstock for electrical generation, much as we harvest methane from landfills here in Tucson; or 2) the prickly pear pads can be dehydrated using solar energy, then pelleted and used as a co-combustion fuel in coal-fired plants. The cactus plantations will have to be irrigated and fertilized to allow a harvest every six months. An added benefit, if the project proves feasible, is that this biofuel is produced from a non-food crop and will provide year-round jobs rather than seasonal employment common to most crops. The goal of the project is to produce at least the equivalent of 40 tons dry matter per hectare per year which they deem competitive with other biofuels.

The Measure of an Earthquake

We heard that the recent Japanese earthquake measured 8.9. What does that number mean? The number used to refer to the Richter Scale, but now refers to the moment magnitude scale, but the numbers are calculated so that they are the same in both scales. The moment scale measures the size of an earthquake in terms of the rigidity of the earth, the amount of movement and the size of the area affected. In other words, the amount of wiggle on a seismograph. Both the Richter and moment scales are logarithmic, meaning that an earthquake of size 7 is 10 times stronger than an earthquake of size 6. But the amount of energy released is another matter.

Lee Alison, Arizona State Geologist, explains on his blog:

How does the Japan earthquake of magnitude 8.9 compare to other recent large quakes?

The news media do a better job than they used to of noting that each magnitude number is 10 times that of the lower number. But most everyone assumes that refers to the relative amount of energy released by the quake – comparable to measuring the power of atomic bombs for instance.

Not true.

The magnitude is a measure of the amplitude of the seismic waves. But each 1.0 magnitude increase is equal to approximately a 32 times increase in energy release. Each increase of magnitude by 2.0 equals 32 x 32 or (about) 1,000 times increase in energy released.

The M8.9 Japan quake released the equivalent of 336 megatons of TNT. In comparison, last month’s Christchurch, New Zealand M6.3 quake was equal to 43 kilotons, and last year’s M7.0 Haiti quake was equal to 474 kilotons.

The Japan quake was about 7814 times bigger than the Christchurch quake and 709 times larger than the Haiti quake.

I’ve simplified this in regards to Richter magnitude vs moment magnitude but my intent is to emphasize the power of the Japan quake.

 The strongest recorded earthquake was in Valdivia, Chile, May 1960. It measured 9.5. The second largest, measuring 9.2, was in Alaska in 1964. The 1906 earthquake in San Francisco had a moment magnitude of 7.9. The U.S. Geological Survey says that an earthquake of about 8.0 or more occurs on average of once per year.

The Alaskan earthquake is interesting because it demonstrated a certain property of some clays that contributed to the extensive damage in Anchorage. Some clays are thixotropic, meaning that when subject to shear stress, that is, you shake them, they turn to liquid. Thixotropic substances are normally thick and viscous, but turn very liquid under shear stress. You have experienced thixotropy with a ketchup bottle.

Besides shaking and breaking, seismic sea waves, tsunamis, are the greatest danger. Tsunamis are long-wavelength ocean waves with energy extending from the sea surface to the ocean floor. When the wave reaches shallow water near the coast, all that energy is concentrated into a smaller and smaller space, hence its destructive force. In mid-ocean, a tsunami is barely noticeable.

You can see a list of the largest recorded earthquakes here.

Most earthquakes occur near the edges of tectonic plates, but there are some intra-plate quakes as well. For instance, on December, 16, 1811, a large earthquake, estimated strength 7.2-8.1, occurred near New Madrid, Missouri. New York is not immune to earthquakes either. See here for earthquake information by state.

 And some earthquakes are caused by human intervention. I experienced the Denver earthquakes of 1967-1968. The Rocky Mountain Arsenal near Denver was disposing of waste material by pumping it down more than 12,000 feet beneath the surface. That lubricated a deep range-front fault and caused is to slip.

 Here is a map from the US Geological Survey showing locations of major earthquakes since 1900. The pattern describes the boundaries of major tectonic plates and the volcanoes of Hawaii.

worldearthquakes-USGS