Geophysicist Talks Earthquakes and Volcanic Eruptions

Thursday, April 29 10:02 am

The 7.2-magnitude earthquake in Mexico, the devastating earthquake in Haiti, and the recent eruption of Iceland’s Eyjafjallajokull volcano all serve as reminders of the power of geological events.  On May 6, Dr. Stephen Malone, who was the principal scientist responsible for the seismic monitoring of Mount St. Helens, will speak at the American Museum of Natural History about the science behind forecasting earthquakes and volcanic eruptions.

Dr. Malone recently shared some thoughts about the most important type of earthquake forecast, reducing earthquakes’ devastating effects, and the relationship between earthquakes and volcanic eruptions.

What are some of the latest advances in predicting earthquakes? How much progress has been made in the last decade?

No real progress has been made in the deterministic prediction of a specific earthquake. However, the long-term statistical forecasting of earthquakes is continually being refined. Since the primary hazard from earthquakes is the failure of our engineered structures—buildings, bridges, factories—the most important forecast is that which tells the engineer how strong a building should be built to withstand them.

Do you think there is any hope that in the future we will receive warning before a catastrophic earthquake such as the recent one in Haiti?

Earthquakes may be inherently unpredictable. However, there are two improvements I see on the horizon that may help significantly reduce the disastrous effects of future earthquakes. We may be able to indicate areas or regions where the probability of a large earthquake is higher than in the past, allowing for extra mitigation to take place. Second, the technology currently exists to provide warning seconds to a minute or so before strong shaking arrives at vulnerable locations distant from an earthquake that has already started.

What sorts of patterns do earthquakes and volcanic eruptions tend to follow?

It is currently not possible to say when a volcano will erupt in more distant future, but most do show signs of unrest at least days to weeks before they erupt. Earthquakes, on the other hand, occur suddenly. Typically a large earthquake will be followed by a decreasing number of smaller earthquakes, or aftershocks, and occasionally may be preceded by small earthquakes.

What can earthquake activity tell us about volcanic eruptions, and vice versa?

Unfortunately, it is a one-way street. What we call “seismicity patterns,” tracking the timing and location of small earthquakes at volcanoes, allow us to infer the forces being generated by molten rock as it rises toward the earth’s surface. Such seismicity is rarely large or hazardous in its own right. The dangerous earthquakes are those caused by the much larger plate tectonic forces that cause the failure of major weaknesses in the earth’s crust, such as the San Andreas fault.

You were the principal scientist responsible for the seismic monitoring of Mount St. Helens. What did that involve? What did you learn about eruptions during that time?

Monitoring Mount St. Helens, like other volcanoes, involves operating real-time seismic stations on and near the volcano, recording the resulting seismic data on computers and doing a combination of automatic, computer analysis and manual review on a routine basis. Since 1980, when Mount St. Helens first became active, I have been involved in developing ways to recognize signs of unrest and with automating that recognition process as much as possible to increase the sensitivity and reliability of detecting and interpreting precursors to eruptions. It is very rare for volcanoes to erupt dangerously without some warning.

Sand Author Awarded John Burroughs Medal

Wednesday, April 28 12:24 pm

Author Michael Welland was recently awarded the prestigious 2010 John Burroughs Medal for his book Sand: The Never-Ending Story (University of California Press, 2009). Welland, a London-based geologist, flew into New York earlier this month to receive his award during the annual meeting of the John Burroughs Association at a reservations-only luncheon at the American Museum of Natural History. In Sand, Welland examines the science as well as the rich cultural record of sand mixing in tales of artists, mathematicians, explorers, and even a vampire, and relates an epic story of environmental construction and destruction.

The John Burroughs Medal has been given annually since 1926 for books that combine scientific accuracy, firsthand fieldwork, and creative natural history writing. Welland joins an impressive roster of past winners including Rachel Carson, Loren Eiseley, Paul Brooks, Ann Zwinger, Robert Pyle, Richard Nelson, Carl Safina, and Julia Whitty.

Author Michael Welland speaks to the members of the John Burroughs Association at their annual luncheon at the Museum. AMNH/D. Finnin

Where Museum Scientists Will Spend Their Summer

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John Sparks and colleague snorkel in a sinkhole in Madagascar. © P. Chakrabarty

How will you spend your summer? Will you backpack through blisteringly dry heat, cutting the trail as you go and pushing flies out of your eyes? Could you dine on white rice for weeks while camping by a series of shallow, rocky streams?

That’s how Associate Curator John Sparks travels while working to discover undescribed species of fish in northwestern Madagascar. This summer he returns with a portable lab to test hearing in a group of cichlids that have an unusually shaped gas bladder that abuts their inner ear and allows them to pick up sounds from the noisy background of streams. Fellow ichthyologist Melanie Stiassny will also be collecting fish, this time along the Upper Congo River and tributaries of the Kasai that funnel fresh water to western Africa. After years of describing the extraordinary biodiversity of the Lower Congo, she is now searching for its source upriver.

Other curators will also be continuing long-term research projects with the goal of discovering new species. Ornithologist George Barrowclough returns to mountainous British Columbia, where male blue grouse emit loud hoots while sitting high up in conifers. These calls, in part, have led Barrowclough to conduct a genetic study to show that this species is actually two. Norm Platnick will travel to Cuba this summer, the first of many trips now that the Museum is collaborating with the National Museum in Havana. Platnick studies goblin spiders, a poorly understood, nearly microscopic group of arachnids that he’s followed for decades. He estimates that only a fifth of the species are described. Fellow invertebrate specialist Jerome Rozen, who has been studying bees for nearly half a century, will visit eastern Turkey to find and describe for the first time nests of the Ancylini, a tribe of solitary bees whose nesting biology is still not fully known. James Carpenter heads for the western mountains of Hungary to collect yellow jackets, continuing work he began in 1976. Carpenter will also collect spit from yellow-jacket adults because, in some species, adults lack the enzyme to break down protein and rely on larvae to digest the food and to function, in effect, as the stomach of the colony. Read more »

Rose Center Will Go to Space

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A wafer-thin titanium disk — conceived in the labs on the sixth floor of the Museum’s Rose Center for Earth and Space — will launch into space in 2014 with the James Webb Space Telescope. This disk, known as a non-redundant mask, will dramatically improve the telescope’s resolution and contrast by filtering light coming from very bright objects.

“This technique was invented for radio astronomy in the 1950s and revived for ground-based astronomy in the late 1990s,” says Anand Sivaramakrishnan, chief instrumentation scientist in the Museum’s Department of Astrophysics. “But this is the first time it will be used in space.”

Sivaramakrishnan’s team span the Museum, University of Sydney, Cornell University, University of Montreal, Subaru Telescope, Space Telescope Science Institute, and City University of New York.  They have designed non-redundant masks for ground-based spectrographs on the 200-inch telescope at Palomar and the 8 meter Gemini telescope. On the ground, the mask enables the imaging of objects about 100 times fainter than a bright star. But in space, this same tool should be able to detect objects 10,000 times fainter than the nearby bright object or star, helping the Hubble’s sucessor directly image extrasolar planets.

Read more in the official press release.

Preview of Children’s Health and Healthy Ecosystems Panel

Tuesday, April 27 1:49 pm

On April 30, Aaron Bernstein, author of Sustaining Life: How Human Health Depends on Biodiversity, will be part of a panel discussing The Role of Biodiversity and Healthy Ecosystems in Supporting Child Health, an event that is part of an ongoing series celebrating the International Year of Biodiversity at AMNH. Bernstein recently offered a few thoughts on the subject.

Photo by Suzi Camarata

The effect of clean water and food on children’s health is obvious. What are some of the less obvious factors that play a critical role?

Good health depends on good genes and a healthy environment. A quick survey of health problems facing our children today, however, makes it clear that they result not from changes in genes but from changes to the environment. For instance, our children are overweight because they exercise less and eat more than generations past. The increased prevalence of other diseases such as asthma and severe food allergy over the past few decades likewise reflect environmental factors, though identifying what these are has proven difficult.

That being said, the environment is not just a source of illness. Research on childhood exposure to nature suggests that early positive experiences in nature may have benefits across the lifespan, from reduced stress and greater self-confidence to higher achievement in school and lower rates of obesity.

Do you have an example of how depletion of biodiversity has affected children’s health?

With repeated exposure to different kinds of antibiotics, bacteria that survive will be immune to the effects of those antibiotics. Reducing the diversity of bacterial subsets, or strains, selects for bacteria that are resistant to multiple antibiotics.

A common example of this has been the emergence of antibiotic resistant bacteria, such as methicillin resistant Staphylococcus aureus, or MRSA. The prevalence of this infection ranges from 10% to 80% depending upon where one lives. S. aureus causes many kinds of infections in children, including infections of skin and bone as well as pneumonia.

How would you recommend reversing this issue?

First, and especially for children, only take antibiotics if you absolutely need to.

Second, although our data are limited, an estimated 70% of antibiotics given in the United States are given to livestock. In one study at the University of Iowa, 70% of a sample of pigs reared in Illinois and Iowa were colonized with MRSA. MRSA has been transmitted to humans from contaminated of infected meat. Other resistant bacteria that can infect humans have been found in cattle and chickens. To prevent the appearance of resistant bacteria in livestock, we need to overhaul how our livestock are raised. For that, we can vote both with our wallets and for candidates who understand the importance of reducing antibiotic use in livestock.

Sponsors include Museum’s Center for Biodiversity and Conservation, the United Nations Environment Programme, the United Nations Children’s Development Programme, and Mount Sinai School of Medicine.

The U.N. proclaimed 2010 as the International Year of Biodiversity. The American Museum of Natural History has joined efforts to refocus the world on biodiversity, the complex tapestry of interconnections at every level that supports life on Earth.