2/24/15: SEISMICITY IN THE US

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 one.

As a continuation of my last post, 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).

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).

A brand new article worth reading: EOS the 'Big One'

All for now-

2/17/15: US WEST COAST S-H-A-K-I-N-G: WELL, OF COURSE!

This week we are exploring the reasons of certain natural hazards (earthquakes/volcanic eruptions) in relation with the location of plate boundaries. 

The North America Plate, where the USA is located (see figure map from USGS) is part oceanic crust and part continental. The relevant plate boundary of this country for geologic activity is on the west side, part of the Ring of Fire, where we have a subduction zone (Alaska) and as we go south, the boundary changes into a transform one (San Andreas Fault). The idea is that if you know which type of boundary you have, you can predict what type of hazard the area will suffer: in transform boundaries, earthquakes are very common (California, should l say more?); in subduction zones, volcanic activity is common (Shasta, Lassen, St. Helens Mountains are volcanoes!).

As a side note (as it is NOT a plate boundary), the Hawaiian Islands are a hot spot, with volcanic activity and earthquakes.

I live in the West coast and I teach geology. Perfect.

2/10/15: MOLYBDENUM IN THE USA

This week the Geol9 class will explore minerals and rocks and how relevant they are as resources in different parts of the world. In particular, we will pay attention on how hard/soft the material is.

In my case, I chose to work with an element, which the USA is a net exporter of: Molybdenum (yes, I picked the one with the complicated name, well, of course!). With a chemical symbol ‘Mo’, its name comes from the Greek work of ‘lead’ as it was confused with lead ore (like galena) often.

I started searching in the USGS website about mineral data around the world: the USGS International Minerals Statistics and Information website. I also read the Mineral Commodity Summary for 2014, which shows molybdenum (see image from Wikipedia) as a rising star regarding net exports. The USGS 2015 Report on it shows that last year, molybdenum, valued at about $1.8 billion, was produced at 13 mines. Molybdenum ore was produced as a primary product at three mines in Colorado and Idaho; and ten copper mines (in Arizona, Montana, Nevada, New Mexico, and Utah) recovered molybdenum as a byproduct.

How hard is it? Well, it is very hard, but softer and more ductile than tungsten. Molybdenum has a high elastic modulus, and only tungsten and tantalum have higher melting points. Molybdenum is used to alloy many specialty steels. Some other common uses for molybdenum are electrodes, furnace applications, nuclear energy and missile and aircraft parts. Very recently a new application of this element in thin-film transistors was published (see Phys.org paper). It seems like we use it far more times that we think!

On a different note, and as 2015 is the International Year of Soils, I wanted to post a link where you can find out more about related events worldwide: International Year of Soils link. And if you like stickers,…well…go to Free 'I love soil' stickers website and get yours!