A5007107449- earthquake and tectonic studies
- High-pressure geophysics and materials
- Geological and Geochemical Analysis
- Earthquake Detection and Analysis
- Seismology and Earthquake Studies
- Seismic Waves and Analysis
- Geological and Geophysical Studies
- Geophysics and Sensor Technology
- Geochemistry and Geologic Mapping
- Geotechnical and Geomechanical Engineering
- Geological Modeling and Analysis
- Earthquake and Disaster Impact Studies
- GNSS positioning and interference
- Marine and environmental studies
- Seismic Performance and Analysis
- Geology and Paleoclimatology Research
- Seismic Imaging and Inversion Techniques
- Reservoir Engineering and Simulation Methods
- Geophysics and Gravity Measurements
- Earthquake and Tsunami Effects
- Educational Games and Gamification
- Educational Technology and Assessment
- Geological Studies and Exploration
- Astro and Planetary Science
- Rhetoric and Communication Studies
California State University, Bakersfield
2020-2024
Utrecht University
2018-2023
Bakersfield College
2021
Pennsylvania State University
2014-2018
Montana State University
2010
Abstract Recent megathrust events in Tohoku (Japan), Maule (Chile), and Sumatra (Indonesia) were well recorded. Much has been learned about the dominant physical processes zones: (partial) locking of plate interface, detailed coseismic slip, relocking, afterslip, viscoelastic mantle relaxation, interseismic loading. These older observations show complex spatial temporal patterns crustal deformation displacement, significant differences among different margins. A key question is whether these...
Two large earthquakes in the Aleutian subduction zone provide unexpected evidence for low plate interface coupling.
The rates and kinematics of tectonic processes are generally thought to be reflected in the resulting landscape - with sites rapid burial exhumation typically being more rugged or high-relief. Although plate boundary transition that occurs at Mendocino triple junction (MTJ; northern California) represents a fundamental change from subduction translation, California coast ranges is relatively subdued low-relief. Additionally, MTJ region marked by high levels seismicity  indicating...
Abstract The distribution of slip during subduction megathrust earthquakes depends on the deficit that accumulates plate interface prior to event. We develop 3‐D finite element models zones investigate how locked restrict surrounding regions boundary from sliding. What is new we quantify around asperities megathrust. show increasing zero at edge a zone relative motion over distance ~200 km along This area reduced seismic moment up 10 times larger than in asperity alone. Updip areas, trench...
Abstract The largest earthquakes in subduction zones occur where significant interseismic slip deficit has accumulated on the plate interface. Slip accumulates most quickly mechanically locked regions, and these also cause regions around them to accumulate deficit; therefore, large are typically expected rupture areas. locations dimensions of have been difficult resolve using standard techniques available data sets. We develop a new statistical inversion approach that incorporates physical...
Abstract Following the 2016 M w 7.8 Kaikoura earthquake, uncertainty over nature of coseismic rupture developed. Seismological evidence pointed to significant involvement subduction megathrust, while geodetic and field observations a shallow set intracrustal faults as main participants during earthquake. The addition tsunami modeling reported in Bai et al. (2017, https://doi.org/10.1002/2017GL073717 ) places additional constraints on specific location slip, which when combined with other...
Abstract The 2016 moment magnitude 7.8 Kaikoura, New Zealand, earthquake occurred at the southern end of Hikurangi subduction zone where upper plate above shallow megathrust is exposed sub‐aerially. As a result, substantial co‐seismic deformation in rupture was observed geologically and geodetically. We explore relationship between this surface faulting find that greatest fault slip coincident (in time location) with rupture. Models Coulomb stress change demonstrate these faults become...
Abstract On 5 May 2014, a M w 6.2 strike‐slip earthquake occurred in the Mae Lao region of Chiang Rai province Thailand. This took place known faults and caused substantial damage injuries, although had been previously identified as having relatively low hazard. Detailed field reconnaissance deployment dense, temporary, network broadband seismometers allowed details its relationship to seismicity be analyzed. The aftershock sequence associated with this main shock occurs on two well‐defined...
Abstract In April 2017, a sequence of earthquakes offshore Valparaíso, Chile, raised concerns potential megathrust earthquake in the near future. The largest event 2017 was M 6.9 on 24 April, seemingly colocated with last great‐sized region—a 8.0 March 1985. history large this region shows significant variation rupture size and extent, typically highlighted by juxtaposition ruptures interspersed smaller magnitude sequences. We show that ruptured an area between two main slip patches during...
Abstract The details of subduction zone locking place constraints on the characteristics megathrust events. Due to lack significant present‐day seismicity along Cascadia interface, geodetic data are used assess margin. We isolate signal from other tectonic signals within GPS field, plate‐interface locking. Apparent coupling determined by a simple homogenous elastic half‐space inversion cannot everywhere reproduce component field. Consequently, we explore relationships among upper‐plate...
Abstract A devastating tsunami struck Palu Bay in the wake of 28 September 2018 M w = 7.5 earthquake (Sulawesi, Indonesia). With a predominantly strike‐slip mechanism, question remains whether this unexpected was generated by itself, or rather earthquake‐induced landslides. In study we examine potential co‐seismic deformation. To end, present novel geodetic data set Global Positioning System and multiple Synthetic Aperture Radar‐derived displacement fields to estimate 3D surface deformation...
Abstract Botswana is a country with relatively low seismic activity that experienced an unexpected Mw 6.5 earthquake on 3 April 2017. Using data from the first countrywide network, we established catalog for period January 2014 to February 2018. Two areas of elevated were detected. The one Okavango Rift Zone in northern Botswana, area known be active. other associated 2017 mainshock and its aftershocks central Botswana; it follows Paleoproterozoic suture between Limpopo Belt Kaapvaal Craton....
Abstract On 16 September 2015, a M w 8.3 earthquake ruptured the subduction zone offshore of Illapel, Chile, generating an aftershock sequence with 14 6.0–7.0 events. A double source W phase moment tensor inversion consists 7.2 subevent and main 8.2 phase. We determine two slip models for mainshock, one using teleseismic broadband waveforms other static GPS InSAR surface displacements, which indicate high north epicenter west‐northwest near oceanic trench. These distributions published in...
We constrain epicentroid locations, magnitudes and depths of moderate-magnitude earthquakes in the 2013–2014 Minab sequence using surface-wave cross-correlations, spectra teleseismic body-wave modelling. estimate precise relative locations 54 Mw ≥ 3.8 48 409 teleseismic, intermediate-period Rayleigh Love-wave cross-correlation measurements. To reduce significant regional biases our we shift to align 6.2 main-shock centroid a location derived from an independent InSAR fault model. Our...
This map shows details of the Aleutian arc not visible in an earlier publication. The extends about 3,000 km from Gulf Alaska to Kamchatka Peninsula. It marks region where Pacific plate subducts into mantle beneath North America plate. subduction is responsible for generation Islands and deep offshore Trench. Relative a fixed plate, moving northwest at rate that increases 55 mm per year arc's eastern edge 75 near its western terminus. In east, convergence plates nearly perpendicular...
There have been 22 M7.5+ earthquakes recorded in the New Guinea region since 1900. The dominant earthquake mechanisms are thrust and strike slip, associated with arc-continent collision relative motions between numerous local microplates. largest was a M8.2 shallow fault event northern Papua province of Indonesia that killed 166 people 1996. Australia-Pacific plate boundary is over 4,000 km long on margin, from Sunda (Java) trench west to Solomon Islands east. eastern section 2,300 long,...
Great (moment magnitude Mw ∼8.0 and larger) subduction megathrust earthquakes are commonly followed by increased rates of normal faulting seismicity. Extensional activity within the subducting slab is amplified when slip propagates close to trench, forearc extension triggered largest (Mw 8.5 events. To better understand these observations, we develop an earthquake cycle model with a realistic geometry stresses that in balance plate interface bulk viscous relaxation. The modeled represent...
First posted September 8, 2015 For additional information, contact: Director, Geologic Hazards Science Center U.S. Geological Survey Box 25046, Mail Stop 966 Denver, CO 80225http://geohazards.cr.usgs.gov/ The Mediterranean region is seismically active due to the convergence of Africa Plate with Eurasia plate. Present day Africa-Eurasia motion ranges from ~4 millimeters per year (mm/yr) in a northwest-southeast direction western ~10 mm/yr (north-south) eastern Mediterranean. plate boundary...
The eastern margin of the Australia plate is one most seismically active areas world due to high rates convergence between and Pacific plates. In region New Zealand, 3,000 km long Australia-Pacific boundary extends from south Macquarie Island southern Kermadec chain. It includes an oceanic transform (the Ridge), two oppositely verging subduction zones (Puysegur Hikurangi), a transpressive continental transform, Alpine Fault through South Island, Zealand. Since 1900, there have been 15 M7.5+...
Abstract Subduction zones host some of Earth's most damaging natural hazards, including megathrust earthquakes and earthquake‐induced tsunamis. A major control on the initiation rupture characteristics subduction is how coupled zone along interface accumulates elastic strain between events. We present results from observations slow slip events (SSEs) in Cascadia occurring during interseismic period downdip fully zone, which imply that orientation accumulation within can vary with depth....
Abstract Greater landward velocities were recorded after six megathrust earthquakes in subduction zone regions adjacent to the ruptured portion. Previous explanations invoked either increased slip deficit accumulation or plate bending during postseismic relaxation, with different implications for seismic hazard. We investigate whether can be expected reproduce this observed enhanced motion (ELM). use 3D quasi‐dynamic finite element models periodic earthquakes. find that afterslip downdip of...