Danielle Sumy
2019-05-29 09:13:33
Please register for *Volcano Variety: Understanding Arcs with Multi-Scale
Seismic Imaging* on *May 29, 2019 2:00 PM EDT* at:
https://attendee.gotowebinar.com/register/8079214038580474115
*Presented by:* Dr. Helen Janiszewski, Carnegie Science DTM
*Abstract: *While evidence for variety in volcano structure and eruptive
styles abounds at the earth's surface, magmatic architectures at volcanoes
tens of kilometers beneath the earth's surface and the ultimate causes of
such variety remain enigmatic. At individual volcanoes, magmatic structures
in the mid- to lower-crust have typically been difficult to geophysically
or petrologically constrain. New results at two volcanoes in the Aleutian
island arc - Akutan and Cleveland, which despite being only ~ 300 km from
each other have different recent eruptive histories - reveal seismically
low-velocity regions in the mid- to lower-crust, likely caused by a region
of partial melt. However, the spatial and vertical extents of these low
velocity zones beneath the two volcanoes vary substantially implying
differing magmatic architectures. The causes are still unknown, although
the depth to the top of the subducting crust varies by nearly 20 km perhaps
implying different structures in the downgoing lithosphere beneath these
volcanoes. The seismic structure of the downgoing Pacific plate in this
region of the Aleutians is relatively poorly constrained at the scale of
arc-volcano spacing. Instead we investigate the Cascadia subduction zone,
where the recent onshore-offshore Cascadia Initiative seismic experiment
has allowed seismic imaging at these scales. Prior to subduction, the
oceanic plate deviates from simple thermal cooling models with along-strike
variation observed at scales similar to variation in arc properties,
suggesting that there may be more heterogeneity in oceanic lithosphere than
previously thought. This represents an important consideration for
understanding many tectonic phenomenon, including the input to volcanic arc
systems, and demonstrates the need for future experiments both focused on
understanding the role of structures in the subducting plate in conjunction
with detailed imaging of individual volcanoes.
After registering, you will receive a confirmation email containing
information about joining the webinar. *PLEASE NOTE: Registration does not
confirm or guarantee you will have a spot during the webinar, as we are
limited to 500 participants. Please hop on the webinar early for your best
chances to see the webinar live. **Remember that allIRIS w**ebinars are
archived for later viewing at*
https://www.youtube.com/playlist?list=PLD4D607C2FA317E6D
*Any questions?* Contact us at webinar<at>iris.edu
Seismic Imaging* on *May 29, 2019 2:00 PM EDT* at:
https://attendee.gotowebinar.com/register/8079214038580474115
*Presented by:* Dr. Helen Janiszewski, Carnegie Science DTM
*Abstract: *While evidence for variety in volcano structure and eruptive
styles abounds at the earth's surface, magmatic architectures at volcanoes
tens of kilometers beneath the earth's surface and the ultimate causes of
such variety remain enigmatic. At individual volcanoes, magmatic structures
in the mid- to lower-crust have typically been difficult to geophysically
or petrologically constrain. New results at two volcanoes in the Aleutian
island arc - Akutan and Cleveland, which despite being only ~ 300 km from
each other have different recent eruptive histories - reveal seismically
low-velocity regions in the mid- to lower-crust, likely caused by a region
of partial melt. However, the spatial and vertical extents of these low
velocity zones beneath the two volcanoes vary substantially implying
differing magmatic architectures. The causes are still unknown, although
the depth to the top of the subducting crust varies by nearly 20 km perhaps
implying different structures in the downgoing lithosphere beneath these
volcanoes. The seismic structure of the downgoing Pacific plate in this
region of the Aleutians is relatively poorly constrained at the scale of
arc-volcano spacing. Instead we investigate the Cascadia subduction zone,
where the recent onshore-offshore Cascadia Initiative seismic experiment
has allowed seismic imaging at these scales. Prior to subduction, the
oceanic plate deviates from simple thermal cooling models with along-strike
variation observed at scales similar to variation in arc properties,
suggesting that there may be more heterogeneity in oceanic lithosphere than
previously thought. This represents an important consideration for
understanding many tectonic phenomenon, including the input to volcanic arc
systems, and demonstrates the need for future experiments both focused on
understanding the role of structures in the subducting plate in conjunction
with detailed imaging of individual volcanoes.
After registering, you will receive a confirmation email containing
information about joining the webinar. *PLEASE NOTE: Registration does not
confirm or guarantee you will have a spot during the webinar, as we are
limited to 500 participants. Please hop on the webinar early for your best
chances to see the webinar live. **Remember that allIRIS w**ebinars are
archived for later viewing at*
https://www.youtube.com/playlist?list=PLD4D607C2FA317E6D
*Any questions?* Contact us at webinar<at>iris.edu
