2/29/16: Minimizing Volcanic Hazards: USGS Alert Codes

This week Geol9 is exploring the volcanic hazards in different countries and their warning systems. I’ll be focusing on the US.

There are several ways we minimize the danger of volcanic activity (apart from the obvious of ‘getting out of the way’…(J:

• ·   Forecasting (earthquakes as early warnings -although in 2014 a Japanese volcano erupted without any previous seismicity (livescience article), land swelling before eruption, gas emissions, etc.)
• 
  
• ·  Volcanic Alert Codes (USGS): the levels of alert and the aviation code levels commonly change at the same time. A non-erupting volcano will have a green icon, and a red one indicates an imminent eruption (see USGS Alert Codes).

Today the US hazards map shows the following U.S. volcanoes as to be above normal background (elevated unrest or eruptions) or have shown activity that warranted an Information Release (for example, an earthquake swarm):

Shishaldin, Cleveland, Mauna Loa Alert Level=ADVISORY. Aviation Color Code=Yellow.

Kilauea Alert Level=WATCH. Aviation Color Code=Orange. 

Note: this one has been erupting for 33 years! (see more here).

More information @

http://www.volcanodiscovery.com/news.html

http://volcanoes.usgs.gov/vhp/updates.html

http://www.wired.com/2016/01/keep-an-eye-out-for-these-volcanoes-in-2016/

All for now-

2/14/16: Only For Quake Lovers: Exploring Seismicity and Mitigation Strategies

If I want to know something about earthquakes, the first websites I go to are: the USGS Real Time Earthquakes Website or the IRIS monitoring website.

This week we are exploring seismicity and what countries do to prevent/mitigate the hazard.

Re: the first issue, the new 2014 US map of seismicity (see image from USGS) shows the (obvious, in pink) ring of fire portion on the West coast but also a central area in the middle of the plate. I’d like to talk a bit more about this non-obvious one. This area, called the New Madrid Zone was shaken by a M8(!) in 1811. The reason for the activity is a very old intraplate rift placed below the area (see image from http://showme.net).

A great new blog post summarizes nicely the Cascadia subduction Zone dangers....

Re: the second issue, I want to focus on a brand new effort by the USGS: the ShakeAlert system, developed for the West coast using some of the existing systems. Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of an EEW (Earthquake Early Warning) system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds, depending on the distance to the epicenter of the earthquake. 

A few seconds of warning might make all the difference (enough to stop transit/elevators and to drop, cover, hold on). All for now-

2/7/16: Introduction to Geological Activity at Plate Tectonic Boundaries

This week we are exploring plate tectonics and how the location of each country is affected by its position respect to plate boundaries.

The NOAA map shows clearly how the Easter US is a passive margin and the Western side of the country is a very active one, with the Pacific Plate, Cocos, Juan de Fuca plates connecting to the North American plate. Not a surprise we are on the ‘Ring of Fire’, where a lot of the volcanic and seismic activity happens!

Of course, there are a few exceptions, like the activity of Hawaii (hot spot) or the New Madrid area (ancient rift), both not at plate boundaries, but is for some other time.

We might not know when events like volcanic eruptions or big earthquakes will happen, but if you know your Tectonics, you definitely know where the do!

Other interesting Plate Maps can be found at USGS or Esri: interactive. All for now-