Department Logo for Earth, Planetary, and Space Sciences

iPlex Lunch - spring-2018

Extraterrestrial Seismology: Off to Mars and signal and noise on icy ocean worlds

April 4, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Mark Panning - JPL
See Event on Google.
Subscribe to Calendar

The InSight mission is planned to launch in May of this year, and will hopefully be returning seismic and other geophysical data from Mars by the end of 2018. Meanwhile, mission concepts that include seismometers landing on the icy ocean worlds of Europa and Titan are in active development, while the planetary science decadal survey has prioritized a possible new geophysical network on the Earth’s moon. Seismology on other planetary bodies may be entering a new golden age after a long stretch with no new data since the 1970’s. Seismology on other planets presents a different set of challenges than it does on Earth and this talk will look at some of those challenges for Mars and icy ocean worlds, but it is critical in order to advance our knowledges of the interiors of bodies beyond Earth to help us understand how planets form and evolve in our solar system and beyond.

3D deformation in the 2016 Mw 7.8 Kaikoura, New Zealand earthquake from optical satellite image correlation

April 11, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Robert Zinke - USC
See Event on Google.
Subscribe to Calendar

The 14 November 2016 MW 7.8 Kaikoura, New Zealand earthquake produced up to ~12 m of lateral surface displacement, and up to ~8 m of vertical surface displacement. We use a novel version of COSI-Corr optical image correlation software to capture coseismic deformation in three dimensions using high-resolution WorldView satellite imagery. This technique is capable of providing precise (< 1 m precision) measurements of both lateral and vertical displacement across large areas (100’s of km2). Because our 3D COSI-Corr results encompass both near-field (“on-fault”) and far-field (“off-fault”) deformation, they are ideal for facilitating comparison of traditional field measurements (which commonly miss far-field deformation), with more regional patterns of deformation. Understanding how on-fault field measurements reflect broader patterns of strain release in earthquakes is essential for the proper interpretation and use of geologic measurements of prehistoric fault displacements, and for understanding the controls on the 3D distribution of near-surface deformation in large earthquakes.

Eruption Dynamics of Mud Volcanoes and Geysers

April 18, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Max Rudolph - UC Davis
See Event on Google.
Subscribe to Calendar

Geysers and mud volcanoes erupt with greater frequency, and generally with less destructive consequences than their magmatic counterparts. However, their dynamics are in many ways similar to magmatic systems. Like magmatic volcanoes, mud volcanoes are driven by gas expansion and exsolution and regulated by the rheological properties of a dense particle suspension. I will present insights into the subsurface dynamics of the ongoing Lusi mud eruption in East Java, Indonesia constrained by satellite radar interferometry and volcano deformation source modeling. In the second half of the talk, I will present recent work on internal oscillations in geysers. In-situ pressure measurements within the conduit of Old Faithful Geyser in Yellowstone National Park revealed meter-level water column oscillations with a dominant period of 0.7-1 s during the recharge phase between eruptions. I will present progress towards a mechanical model of these oscillations based on theory and laboratory experiments and discuss its applicability to magmatic systems.

Geomorphic Controls on Vs30 Distribution in southern California/New Measurement Method for Multi-Mode Surface Wave Dispersion Using a Transdimensional Bayesian Approach

April 25, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Haotian Xu - UCLA
  • Jessica Lin - UCLA
See Event on Google.
Subscribe to Calendar
Seminar Description coming soon.

Earthquakes in the Southland: Natural or Unnatural Disasters?

May 2, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Susan Hough - USGS Passadena
See Event on Google.
Subscribe to Calendar

It is now well established that the sharp rise in seismicity in the central United States since 2009 is due to human activity, in particular the deep injection of waste water generated by unconventional fossil fuel production (hydraulic fracturing). It has long been assumed that, in California, so-called induced earthquakes do not contribute significantly to earthquake rates, or hazard. Indeed, it is safe to assume that, overwhelmingly, seismic hazard in California stems from active tectonic processes along the plate boundary that runs through the State. Looking back, however, at some of the moderately large earthquakes that struck the Southland during the early 20th century, there is evidence for an association with primary oil production during the early oil boom years in the Los Angeles Basin and elsewhere. A key factor was production depth; I show that the reach of significant stress change typically extends 2-3 km away from a production horizon, vertically as well as horizontally. Thus, if production wells reach depths of 2-3 km, stress perturbations are potentially significant at the top of the seismogenic crust. While the results suggest that there can be a risk of significant induced earthquakes from conventional oil production, the rate of natural earthquakes within the Los Angeles Basin might actually be lower than previously estimated.

Array-based tsunami early warning system and its application to tsunami offshore Ventura, California/Honeycombs on Mars: where are the bees?

May 9, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Yuqing Xie - UCLA
  • Margaret Deng - UCLA
See Event on Google.
Subscribe to Calendar
Seminar Description coming soon.

Seismic probes of Earth's core: low and high frequency investigations

May 16, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Jessica Irving - Princeton
See Event on Google.
Subscribe to Calendar

Earth’s core, the deepest region of our planet, stores heat used for plate tectonics and generates Earth’s magnetic field, yet details of its nature remain uncertain. The composition of the outer core, and the inner core which is slowly crystallizing at the center of the Earth, is not fully known — the core contains roughly a third of the mass of the Earth, yet we do not know which light elements are alloyed with the core’s iron and nickel. The outer core is thought to be well-mixed for the most part, but may contain stratified layers at its boundaries. The slowly growing inner core exhibits seismic heterogeneity at a variety of length-scales. Both short period body-wave data, comprising seismic waves which travel through either the outer core or both the outer and inner core, and long period normal mode frequencies, corresponding to vibrations of the whole Earth, can be used to enhance our understanding of the core. This colloquium will address a variety of the seismological features which are present in the core, from the radially varying velocity and density of the outer core, through to the possibility of “hemispherical” differences in anisotropic texture and smaller scale variation in the inner core.

From deep wastewater disposal to earthquakes: Lessons from the 2011 M5.7 Prague, Oklahoma earthquake

May 23, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Elizabeth Cochran - USGS Passadena
See Event on Google.
Subscribe to Calendar

Recently, Oklahoma experienced an earthquake crisis, with seismicity rates increasing to unprecedented levels as energy production expanded into new types of fields. The 2011 M5.7 Prague, Oklahoma earthquake was a bellwether, revealing the hazards of induced seismicity even before there was general recognition and acceptance that wastewater disposal was causing increased seismicity. This talk will explore the complex earthquake sequence, and examine characteristics of the sequences that may allow us to identify and differentiate induced seismicity from natural earthquakes.

Reconciling structural and paleomagnetic data from the Chocolate Mountains anticlinorium / Wide Stepovers of the Mw 7.8 Kaikoura Earthquake

May 30, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Kevin Coffey - UCLA
  • Aileen Zhang - UCLA
See Event on Google.
Subscribe to Calendar
Seminar Description coming soon.

TBA - Surya Pachhai

June 6, 2018
noon - 1 p.m.
Geology 1707

Presented By:

  • Surya Pachhai - UCSD
See Event on Google.
Subscribe to Calendar
Seminar Description coming soon.