Have you ever wondered...Top USGS FAQs for 2014

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Did you ever wonder...

Ever wonder just what “fracking” is, or the meaning of the karat mark on gold jewelry, or how natural features get named? These are just a few of the over more than million page views the USGS FAQ site gets in a year.

This year’s top questions mainly focused on hazards, with earthquake questions being the most frequent.

The most commonly visited FAQ was: Can you predict earthquakes? The answer is no, neither the USGS nor any other scientists have ever predicted a major earthquake. They do not know how, and they do not expect to know how any time in the foreseeable future. However based on scientific data, probabilities can be calculated for potential future earthquakes. And USGS is working on an earthquake early warning system that may eventually provide seconds-to-minutes of advance warning.

Seismographs at the U.S. Geological Survey record (1) north-south horizontal, (2) east-west horizontal, and (3) vertical components of the earthquake.

Image: Seismographs at the U.S. Geological Survey
Seismographs at the U.S. Geological Survey record (1) north-south horizontal, (2) east-west horizontal, and (3) vertical components of the earthquake.
J.K. Nakata, U.S. Geological Survey
Public domain

The next most common question was about measuring earthquakes — How are earthquakes recorded? How are earthquakes measured? How is the magnitude of an earthquake determined?Scientists use magnitude to characterize the relative size of an earthquake. It is based on measurement of the maximum motion recorded by a seismograph, and the most commonly used are (1) local magnitude (ML), commonly referred to as “Richter magnitude,” (2) surface-wave magnitude (Ms), (3) body-wave magnitude (Mb), and (4) moment magnitude (Mw). The different measurement scales then begs the question (from almost 11,000 people): What are the different magnitude scales and why are there so many? Each magnitude is valid for a particular frequency range and type of seismic signal. Because of the limitations of all three magnitude scales, ML, mb, and Ms, a new, more uniformly applicable extension of the magnitude scale, known as moment magnitude, or Mw, was developed.

How do volcanoes erupt?” broke up the list of earthquake questions, with most visits to that FAQ page coming after the eruption of Kileaua Volcano in Hawaii that began on June 27.  And then it was back to earthquakes: Can animals predict earthquakes? Although there is anecdotal evidence of animals exhibiting strange behavior, consistent and reliable behavior before a seismic event has not been documented

A key question about safety during an earthquake was also quite frequently visited, with people wondering, “What should I do during an earthquake?” What you should do varies a bit based on where you are, inside, outside, driving, or in a mountainous area. And after an earthquake there are also steps you can take to protect yourself.

There was some curiosity about “The Golden State,” with inquirers wondering: “Will California eventually fall into the ocean?” In a word, no, although Los Angeles and San Francisco will one day be adjacent to one another!

Erupting vents on Mauna Loa’s northeast rift zone near Pu‘u‘ula‘ula (Red Hill) on Mar. 25, 1984, sent massive ‘a‘ā lava flows down the rift toward Kūlani.

Image: Lava flows on Mauna Loa
Erupting vents on Mauna Loa’s northeast rift zone near Pu‘u‘ula‘ula (Red Hill) on Mar. 25, 1984, sent massive ‘a‘ā lava flows down the rift toward Kūlani.
RBM, U.S. Geological Survey Hawaiian Volcano Observatory
Public domain

And then we were back to volcanoes: What are the different types of volcanoes?  And How many active volcanoes are there on Earth?  First some basics: The largest and most explosive volcanic eruptions eject tens to hundreds of cubic kilometers of magma onto the Earth’s surface. When such a large volume of magma is removed from beneath a volcano, the ground subsides or collapses into the emptied space, to form a huge depression called a caldera. Some calderas are more than 25 kilometers in diameter and several kilometers deep.

So how many types are there? There are three types of volcanoes: Cinder cone/Scoria cone, Composite volcanoes/Stratovolcanoes, and Shield volcanoes.

Cinder cones are the simplest type of volcano. They are built from particles and blobs of congealed lava ejected from a single vent.

Some of the Earth’s grandest mountains Mount Fuji in Japan, Mount Cotopaxi in Ecuador, Mount Shasta in California, Mount Hood in Oregon, Mount St. Helens and Mount Rainier in Washington are composite volcanoes — sometimes called stratovolcanoes.  They are typically steep-sided, symmetrical cones of large dimension built of alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs and may rise as much as 8,000 feet above their bases.

And how many active volcanoes are there? There are about 1500 potentially active volcanoes, and about 500 have erupted in historical time.

We’ll finish of the most frequently visited FAQs list with: “What is the difference between a tsunami and a tidal wave? Good question. Both are sea waves, but a tsunami and a tidal wave are two different and unrelated phenomenona. A tidal wave is the wave motion of the tides. A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth. Tsunamis are ocean waves triggered by large earthquakes that occur near or under the ocean, volcanic eruptions, submarine landslides, and by onshore landslides in which large volumes of debris fall into the water. Tsunamis cause major damage and loss of life. “Tidal wave” used to be the popular term for what are actually tsunamis.

A drill rig in the Permian Basin of West Texas being used to drill a well which will be hydraulically fractured to produce natural gas. A sound control wall can be seen in the rear of the drill pad to reduce the amount of noise reaching surrounding areas. Photo Credit: Hannah Hamilton, USGS

Looking up at an oil drill
A drill rig in the Permian Basin of West Texas being used to drill a well which will be hydraulically fractured to produce natural gas. A sound control wall can be seen in the rear of the drill pad to reduce the amount of noise reaching surrounding areas. Hannah Hamilton, USGS

USGS has over 1400 FAQ pages that answer questions from biology to climate change to mapping to water. At USGS FAQs you can find answers to the less common questions, such as:

Since we started off with “Fracking”, lets end there: Fracking is an informal name for hydraulic fracturing, an oil and gas well development process that typically involves injecting water, sand, and chemicals under high pressure into a bedrock formation via the well. This process is intended to create new fractures in the rock as well as increase the size, extent, and connectivity of existing fractures.

USGS information can be accessed 24/7 on the USGS FAQ site, and there are Science Information Services staff available from 8AM to 8PM (Eastern) to answer questions by phone at 1-888-275-8747 or by webchat, Monday through Friday (but not on federal holidays). Got questions? ASK USGS!