Andrew Frassetto
2012-11-19 22:25:26
The next IRIS webinar will present "Three-dimensional inversion of
EarthScope magnetotelluric data: crustal and mantle electrical
conductivity of the NW US" on November 27, 2012 from 3-4 pm ET (8-9 pm UTC).
To attend, register by entering your name and email here:
https://www2.gotomeeting.com/register/817110738. You will then receive a
confirmation email containing information about joining the webinar. The
webinar will be recorded and available for viewing afterward. Following
the presentation there will be the opportunity to direct questions to
the speaker. More information on IRIS research webinars, including links
to previously recorded presentations and related materials, may be found
here: http://www.iris.edu/hq/webinar/
Please contact Andy Frassetto (andyf<at>iris.edu) with any additional
questions.
Presenter: Gary Egbert, Oregon State University
Summary: "Long period (10-20,000s) magnetotelluric (MT) data are being
acquired in a series of temporary arrays deployed across the continental
USA through the EMScope component of EarthScope. The MT data are highly
sensitive to fluids and melt, and thus provide a valuable complement to
other observational components of EarthScope. In this presentation we
will review basics of the MT method, and then discuss 3D inversion and
interpretation of EMScope data from the Northwestern US, acquired in
2006-2011. For the inversion we use full impedances and vertical field
TFs from 325 sites on a quasi-regular grid (nominal ~70km spacing of the
seismic TA) covering a rectangular area from NW Washington to NW
Colorado. The inverse solutions reveal extensive areas of high
conductivity in the lower crust and uppermost mantle beneath the
extensional Basin and Range, High Lava Plains, and Snake River Plain
provinces, as well as beneath the Cascade volcanic arc. These high
conductivities can only be explained by partial melt and/or magmatic or
subduction related saline fluids. Stable Proterozoic lithosphere in the
northeastern part of the domain is generally much more resistive, with
the thickest resistive sections coinciding with the Wyoming and Medicine
Hat Cratons. Oceanic lithosphere of the subducting Juan de Fuca Plate is
clearly imaged as a zone of very high resistivity beneath the Coast
Ranges. Other prominent resistive zones in the NW part of the domain may
represent relict oceanic lithosphere: the accreted “Siletzia” terrane
beneath the Coast ranges and Columbia Embayment, and a deep vertical
resistive feature just to the east—the seismically fast “slab curtain”
beneath Eastern Idaho that others have interpreted to be stranded
Farallon lithosphere. Aesthenospheric conductivities are generally
consistent with laboratory results for moderately hydrated (~200-300
ppm) olivine, with a potential temperature of ~1300C. Higher
aesthenospheric conductivities occur east of the Rocky Mountain front,
where greater hydration or higher temperatures are required, and in the
back arc, where broad fingers of high conductivity rise to very shallow
depths. The most prominent of these features occurs in Washington State,
where anomalously high conductivities dip to the S-E, suggesting
aesthenospheric flow around the slab curtain. There are also some areas
of reduced aesthenospheric conductivity (beneath the slab curtain, and
south of the Yellowstone hot spot), suggesting lower temperatures and/or
depletion of volatiles in these areas."
System Requirements
PC-based attendees
Required: Windows® 7, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.5 or newer
EarthScope magnetotelluric data: crustal and mantle electrical
conductivity of the NW US" on November 27, 2012 from 3-4 pm ET (8-9 pm UTC).
To attend, register by entering your name and email here:
https://www2.gotomeeting.com/register/817110738. You will then receive a
confirmation email containing information about joining the webinar. The
webinar will be recorded and available for viewing afterward. Following
the presentation there will be the opportunity to direct questions to
the speaker. More information on IRIS research webinars, including links
to previously recorded presentations and related materials, may be found
here: http://www.iris.edu/hq/webinar/
Please contact Andy Frassetto (andyf<at>iris.edu) with any additional
questions.
Presenter: Gary Egbert, Oregon State University
Summary: "Long period (10-20,000s) magnetotelluric (MT) data are being
acquired in a series of temporary arrays deployed across the continental
USA through the EMScope component of EarthScope. The MT data are highly
sensitive to fluids and melt, and thus provide a valuable complement to
other observational components of EarthScope. In this presentation we
will review basics of the MT method, and then discuss 3D inversion and
interpretation of EMScope data from the Northwestern US, acquired in
2006-2011. For the inversion we use full impedances and vertical field
TFs from 325 sites on a quasi-regular grid (nominal ~70km spacing of the
seismic TA) covering a rectangular area from NW Washington to NW
Colorado. The inverse solutions reveal extensive areas of high
conductivity in the lower crust and uppermost mantle beneath the
extensional Basin and Range, High Lava Plains, and Snake River Plain
provinces, as well as beneath the Cascade volcanic arc. These high
conductivities can only be explained by partial melt and/or magmatic or
subduction related saline fluids. Stable Proterozoic lithosphere in the
northeastern part of the domain is generally much more resistive, with
the thickest resistive sections coinciding with the Wyoming and Medicine
Hat Cratons. Oceanic lithosphere of the subducting Juan de Fuca Plate is
clearly imaged as a zone of very high resistivity beneath the Coast
Ranges. Other prominent resistive zones in the NW part of the domain may
represent relict oceanic lithosphere: the accreted “Siletzia” terrane
beneath the Coast ranges and Columbia Embayment, and a deep vertical
resistive feature just to the east—the seismically fast “slab curtain”
beneath Eastern Idaho that others have interpreted to be stranded
Farallon lithosphere. Aesthenospheric conductivities are generally
consistent with laboratory results for moderately hydrated (~200-300
ppm) olivine, with a potential temperature of ~1300C. Higher
aesthenospheric conductivities occur east of the Rocky Mountain front,
where greater hydration or higher temperatures are required, and in the
back arc, where broad fingers of high conductivity rise to very shallow
depths. The most prominent of these features occurs in Washington State,
where anomalously high conductivities dip to the S-E, suggesting
aesthenospheric flow around the slab curtain. There are also some areas
of reduced aesthenospheric conductivity (beneath the slab curtain, and
south of the Yellowstone hot spot), suggesting lower temperatures and/or
depletion of volatiles in these areas."
System Requirements
PC-based attendees
Required: Windows® 7, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.5 or newer
-
Andrew Frassetto
2013-01-03 00:02:43The next IRIS webinar will present "Communicating Science with the Media
and General Public" on January 9, 2013 from 3-4 pm ET (8-9 pm UTC).
Register to attend, here:
https://www2.gotomeeting.com/register/195605906. You will then receive a
confirmation email containing information about joining the webinar. The
presentation and subsequent Q&A session with the speaker will be
recorded and available for viewing within a few days. More information
on IRIS webinars, including links to previously recorded presentations
and related materials, may be found here: http://www.iris.edu/hq/webinar/
Presenter: Dr. Lucile Jones, United States Geological Survey
Summary: "Communicating scientific and technical information is not a
talent or done by luck. Research and experience reveal the best ways to
connect with an audience to communicate expert information as well as
the uncertainty that sometimes surrounds it. Dr. Lucy Jones has over 20
years of experience and has worked with psychologists, anthropologists
and other social scientists to understand how an audience receives and
responds to risk communication. She will share her insight into how to
communicate scientific research effectively to the media and general
public, and she'll share what researchers in risk communication field
say about how to be most effective."
You may contact Andy Frassetto (andyf<at>iris.edu) with any inquiries.
System Requirements
PC-based attendees
Required: Windows® 7, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.5 or newer
-
Andrew Frassetto
2013-01-09 17:56:43"Communicating Science with the Media and General Public" will be
presented today from 3-4 pm ET (8-9 pm UTC).
Register to attend, here:
https://www2.gotomeeting.com/register/195605906. You will then receive a
confirmation email containing information about joining the webinar. The
presentation and subsequent Q&A session with the speaker will be
recorded and available for viewing within a few days. More information
on IRIS webinars, including links to previously recorded presentations
and related materials, may be found here: http://www.iris.edu/hq/webinar/
Presenter: Dr. Lucile Jones, United States Geological Survey
Summary: "Communicating scientific and technical information is not a
talent or done by luck. Research and experience reveal the best ways to
connect with an audience to communicate expert information as well as
the uncertainty that sometimes surrounds it. Dr. Lucy Jones has over 20
years of experience and has worked with psychologists, anthropologists
and other social scientists to understand how an audience receives and
responds to risk communication. She will share her insight into how to
communicate scientific research effectively to the media and general
public, and she'll share what researchers in risk communication field
say about how to be most effective."
You may contact Andy Frassetto (andyf<at>iris.edu) with any inquiries.
System Requirements
PC-based attendees
Required: Windows® 7, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.5 or newer
-
