Sunset Crater... A millennial

Yeah you're right. This week I visited Sunset Crater. It is the youngest volcano in the San Francisco volcanic field.

Here's a picture of the volcano.

Sunset Crater is a cinder cone just like SP crater. It erupted about a thousand years ago. 

The eruption is characterized as three events. First, a fissure about 6.2 miles long opened up in the ground and began spewing lava and rock. Eventually, the eruption became centered at one end of the fissure. It began to build up the volcano we now know as Sunset Crater. The final event was the lava flow that emerged from the western base of the volcano.

 This flow is named the Bonito lava flow. It is basaltic lava that became rough and jagged as it cooled. There are also cracks in the flow formed by the frictional drag on the upper portion of the lava flow by the fluid lava below. The flow also has "hornitos" or small cones of spattered rock that sprays of lava built up.

Here are some pictures of the Bonito lava flow:

 This photo displays the size of the holes created by escaping gases as the rocks cooled.

This is an example of the cracks that opened within the lava flow.

In the Sunset Crater visitor center, there was a sign describing the seismic station behind the Wupatki visitor center. The nickname of the station is WUAZ. It is not monitoring volcanic activity because there is no real concern about the renewed activity. It is part of the dozen or so stations across the state of Arizona that just monitor for earthquakes. The visitor center had realtime data from the seismometer.

Another interesting piece of data was this map.

You'll notice the seismic activity around Sunset Crater. In some ways it is concerning that we don't exactly know if there is volcanic activity occurring.

But that's what this project will attempt to address.

Bye.

Rachel