Seismological Research Letters: Special Focus Section on Cascadia Initiative to Monitor Northwest Pacific Seismic Risks

August 18, 2015 – Early data coming in from a massive, four-year deployment of seismometers onshore and offshore in the Pacific Northwest are giving scientists a clearer picture of the Cascadia subduction zone, a region with a past and potential future of devastating “megathrust” earthquakes.

The preliminary results from the Cascadia Initiative include a report of previously undetected, small earthquakes offshore, and seismic imaging that reveals new offshore structures at the subduction zone. The reports, published as a focus section in the September-October 2015 issue of Seismological Research Letters (SRL), also provide an update on how well the Initiative’s instruments are operating, including a look at how seafloor pressure monitors can detect tsunamis in the region.

Researchers on the Research Vessel Oceanus retrieve an ocean-bottom seismometer during a 2014 expedition supporting the Cascadia Initiative.
Researchers on the Research Vessel Oceanus retrieve an ocean-bottom seismometer during a 2014 expedition supporting the Cascadia Initiative.
The Cascadia subduction zone (CSZ) is a 1,100-kilometer (680-mile) Pacific fault that runs roughly from Cape Mendocino, California in the south to northern Vancouver Island, British Columbia. The zone marks the place where the Juan de Fuca and Gorda tectonic plates slip beneath the North American plate at a rate of about 2.3 to 4 centimeters (.9 to 1.6 inches) per year. At subduction zones like this throughout the globe, the tremendous strain built up in these crustal collisions has been released in the world’s largest recorded earthquakes. These megathrust quakes include the 2004 magnitude 9.1 Sumatran Andaman earthquake that devastated parts of Indonesia, and the 2011 magnitude 9.0 Tohoku earthquake in Japan.

Read more

SSA Announces 2015 Geo-CVD Student Travel Grant Winners

August 5, 2015 – The SSA Government Relations Committee selected graduate students Gabrielle Tepp of the University of Rochester and Manuel Mendoza of the University of California at Riverside to attend the annual Geosciences Congressional Visits Day (Geo-CVD) in Washington, D.C., September 29-30, 2015.

Each year SSA invites U.S. graduate students to apply for a travel grant to attend Geo-CVD, supplying a grant to cover up to $2000 of travel expenses (transportation, lodging, and food costs), and winners are asked to write a brief report on the experience for publication in the SSA journal, the Seismological Research Letters (SRL). This student member opportunity would not have been possible without the ongoing generous support of SSA members. A new fund has been established for member contributions to supply ongoing support for this program. Look for it when you renew your membership.

Read more

Precariously Balanced Rocks Suggest San Jacinto, San Andreas May Have Ruptured Together in Past

August 4, 2015 – Stacked in gravity-defying arrangements in the western San Bernardino Mountains, granite boulders that should have been toppled long ago by earthquakes are maintaining a stubborn if precarious balance. In puzzling out why these rocks still stand, researchers have uncovered connections between Southern California’s San Jacinto and San Andreas faults that could change how the region plans for future earthquakes.

Precariously-Balanced Rocks
Precariously balanced rocks near Searchlight, NV
Photo by Nick Hinze, Nevada Bureau of Mines and Geology

In their study published online August 5 in Seismological Research Letters (SRL), Lisa Grant Ludwig of University of California, Irvine and colleagues write that the precariously balanced rocks (PBRs) have survived as a result of interactions between the faults that have weakened earthquake ground shaking near the rocks.

One such interaction, the researchers say, might be a rupture that began on the San Andreas Fault but then jumped over to the San Jacinto Fault, near Cajon Pass. “These faults influence each other, and it looks like sometimes they have probably ruptured together in the past,” said Grant Ludwig. “We can’t say so for sure, but that’s what our data point toward, and it’s an important possibility that we should think about in doing our earthquake planning.”

Read more

Eastern Section SSA 2015 Annual Meeting, 6-8 October, Memphis, Tennessee

Update: Abstract Submission Deadline Extended to Wednesday 9/9

U of Memphis University Center

July 22, 2015 – The 87th annual meeting of the Eastern Section of the Seismological Society of America, hosted by the Center for Earthquake Research and Information (CERI) at the University of Memphis, will be held 6-8 October 2015 on the University of Memphis campus in Memphis, Tennessee (an icebreaker event will be held the evening of October 5th).

Oral and poster presentations are welcomed in all areas of seismology, EarthScope in the CEUS, CEUS source studies, NGA East results, CUS earthquake hazards, CEUS geodynamics, CEUS geodesy and GPS, induced seismicity, and any other topic consistent with the SSA objectives.

The abstract submission deadline for the meeting is Friday, September 4th at midnight Pacific time. Registration for the meeting will be accepted online until September 25th (prices go up after September 11th, so if you’re planning to attend register soon to get the early bird discount). For more information, including details of the October 8th field trip , please visit the meeting home page.

Read more

US Geoscientists Mark Your Calendars for the 8th Annual Geosciences Congressional Visits Days, September 29–30

[GeoCVD Logo]

July 20, 2015 – SSA, in collaboration with the American Geosciences Institute (AGI) and many other geoscience societies, invites geoscientists to come to Washington D.C. for the annual Geosciences Congressional Visits Day (GEO-CVD) on September 29–30, 2015. Decision makers need to hear from geoscientists. Join us and many of your colleagues for this two-day event uniting geoscience researchers, professionals, students, educators, engineers, and executives in Washington, D.C. to raise visibility and support for the geosciences!

Read more

Coming in SRL – Focus Sections on Induced Seismicity, the Cascadia Initiative, & the Gorkha Earthquake

[Cover of SRL 86:4]June 15, 2015 – Each of next three issues of Seismological Research Letters (SRL) will showcase a focus section on a timely, noteworthy topic in seismology. The July/August focus section features eight articles on injection-induced seismicity (it was “published ahead of print” online 10 June 2015; see the table of contents). The September/October SRL is scheduled to contain a focus section about the Cascadia Initiative, an onshore/offshore experiment using data from an amphibious array to study the Juan de Fuca, Gorda, and Pacific plates. And the November/December issue is set to include a focus section with some of the first papers to result from the 25 April 2015 M 7.8 Gorkha earthquake in Nepal. SRL focus sections provide a forum for authors to publish—and readers to learn from—six to eight papers on a single current topic in seismology.

To propose a future SRL focus section, contact SRL Editor in Chief Zhigang Peng at

Read more

Latest SSA Journals

August Issue of BSSA Now Available


July 30, 2015 – The complete August 2015 issue of the Bulletin of the Seismological Society of America (BSSA vol. 105, no. 4) is now available to SSA members and institutional subscribers online at GeoScienceWorld and BSSA Online. Click to view the table of contents for the issue. SSA members should click here to access full text or PDFs of all articles from the issue (log in with your SSA username and password required).

Read more

July/August SRL Available

Cover of SRL 86:4.
[SRL Cover Picture]

On the Cover…
Since 2009, the rate of seismicity in the central and eastern United States has increased sharply, as illustrated in the top image on the front cover. Almost all of this increase is attributable to seismicity induced by wastewater that is coproduced during oil extraction (lower right). Traffic-light monitoring systems have been introduced in some areas to mitigate induced seismicity; the lowerleft image illustrates schematically a new risk-matrix approach for traffic-light monitoring. Details can be found in the eight articles of the Focus Section on Injection-Induced Seismicity, published in this issue of SRL.

[ Close ]

July 1, 2015 – Volume 86, Number 4, the July/August 2015 issue of Seismological Research Letters, is now available online at the GeoScienceWorld website.

This issue features a Focus Section on Injection-Induced Seismicity, guest-edited by David W. Eaton and Justin L. Rubinstein, and also includes:

SSA members can access the complete online edition here.

Not a member? Join now to get immediate access.

Read more