Kelin Wang

Geological Survey of Canada · Pacific Geoscience Centre

At the northern Cascadia subduction zone, the subducting Explorer and Juan de Fuca plates interact across a transform deformation zone, known as the Nootka fault zone (NFZ). This study continues the Seafloor Earthquake Array Japan Canada Cascadia Experiment to a second phase (SeaJade II) consisting of nine months of recording of earthquakes using o...

Dense Global Navigation Satellite System (GNSS) observations enable the development of megathrust interseismic locking models for the southern Kurile subduction zone where many great earthquakes have occurred. Inversion of these data assuming uniform elastic Earth has yielded slip deficit rates that are unreasonably high and/or full locking depth t...

At the northernmost extent of the Cascadia subduction zone, the Explorer plate subducts at approximately 2 cm/yr, less than half the rate of the Juan de Fuca plate to the south. The boundary between these two plates is known as the Nootka fault zone, which is one of the focuses of the Seafloor Earthquake Array Japan-Canada Cascadia Experiment (SeaJ...

Localized geodetic deformation of arctan shape around locked strike‐slip faults is widely reported, but there are also important exceptions showing distributed deformation. Understanding the controlling mechanism is important to hazard assessment and geodynamic analysis. Here we use simple finite element viscoelastic earthquake cycle models to inve...

The Nootka fault zone (NFZ) divides the incoming Explorer and Juan de Fuca plates of the Cascadia subduction zone. Three months of seafloor monitoring using 33 ocean‐bottom seismometers off the west coast of Vancouver Island has allowed us to better understand the tectonic configuration and seismogenic characteristics of the NFZ. We have learned th...

Rupture‐zone averaged static stress drop in the 2011 M=9 Tohoku‐Oki earthquake was less than 5 MPa, but it caused a stress reversal in most of the offshore forearc, although the reversal is less well constrained far offshore by earthquake mechanisms because of 20‐ to 30‐km errors in event depths. Using a finite element model of force balance, we de...

For assessing tsunami hazard in northernmost Cascadia, there is an urgent need to define tsunami sources due to megathrust rupture. Even though the knowledge of Cascadia fault structure and rupture behaviour is limited at present, geologically and mechanically plausible scenarios can still be designed. In this work, we use three-dimensional disloca...

This correction stands to correct Figure 7c listing a low minimum slip of 12 m for Case 2 instead of the correct value of 8 m, as stated in the body of the text and depicted on the chart of cumulative slip. The corrected chart explanation and caption are shown below. This error did not affect any of the findings of the paper or the chart itself. Th...

After a great subduction earthquake, viscoelastic stress relaxation causes opposing motion of Earth's surface in the strike-normal direction, with the dividing boundary located roughly above the downdip termination of the rupture. As the effect of the viscoelastic relaxation decays with time, the effect of the relocking of the megathrust becomes in...

Coseismic subsidence along the Cascadia subduction zone causes abrupt relative sea-level (RSL) rise that is recorded in coastal stratigraphy and foraminiferal assemblages. RSL reconstructions therefore provide insight into the magnitude, nature, and frequency of great earthquakes that can constrain deformation models and quantify the seismic risk f...

Numerous observations pertaining to the magnitude 9.0 2011 Tohoku-oki earthquake (offshore Japan) have led to new understanding of subduction zone earthquakes. By synthesizing published research results and our own findings, we explore what has been learned about fault behavior and Earth rheology from the observation and modeling of crustal deforma...

Comparisons of pre-earthquake and post-earthquake microfossils in tidal sequences are accurate means to measure coastal subsidence during past subduction earthquakes, but the amount of subsidence is uncertain, because the response times of fossil taxa to coseismic relative sea-level (RSL) rise are unknown. We measured the response of diatoms and fo...

The Explorer segment of northernmost Cascadia is an end-member “warm” subduction zone with very young incoming plate and slow convergence rate. Understanding the megathrust earthquake potential of this type of subduction zone is of both geodynamic and societal importance. Available geodetic observations indicate that the subduction megathrust of th...

During the 2011 magnitude 9 Tohoku-oki earthquake, very large slip occurred on the shallowest part of the subduction megathrust. Quantitative information on the shallow slip is of critical importance to distinguishing between different rupture mechanics and understanding the generation of the ensuing devastating tsunami. However, the magnitude and...

Supplementary Figures, Supplementary Tables and Supplementary References.

Alignments of fractures and cracks in marine sediments may be controlled by various mechanisms such as horizontal compaction and extension and basement faulting. The orientation of these alignments can be estimated through analyses of S-wave splitting. If sensors in ocean-bottom observations are deployed through free fall, sensor orientation needs...

Moscone South-Poster Hall Tsunamis may be generated by subduction zone earthquakes in four ways: (1) elastic seafloor deformation of the upper plate induced by a buried rupture, (2) enhanced seafloor uplift due to splay faulting, (3) seaward motion of the sloping seafloor due to slip-to-trench rupture, and (4) activation of multiple thrusts and bac...

Tsunami Animations, Time Histories, and Digital Point Data for Flow Depth, Elevation, and Velocity for the Coos Bay Project Area, Coos County, Oregon

On 28 October 2012, an Mw 7.8 earthquake occurred off the west coast of Haida Gwaii, British Columbia. Although past large events at this margin reflect strike-slip motion between the Pacific and North American plates (e.g., 1949 Ms 8.1), this earthquake involved low-angle thrust faulting with a slip direction almost perpendicular to the margin, a...

Purpose: To determine the association of MRI-assessed worsening of tibiofemoral cartilage damage, meniscal damage, meniscal extrusion, separately and together, with progression of radiographic joint space narrowing (JSN). Method and materials: The Multicenter Osteoarthitis Study (MOST) Study is a cohort study of subjects with or at risk for knee...

After a large subduction earthquake, crustal deformation continues to occur, with a complex pattern of evolution. This postseismic deformation is due primarily to viscoelastic relaxation of stresses induced by the earthquake rupture and continuing slip (afterslip) or relocking of different parts of the fault. When postseismic geodetic observations...

This report builds on and supercedes Phase I of a demonstration Probabilistic Tsunami Hazard Assessment (PTHA) study of Crescent City, California [23], which developed an improved methodology for PTHA and associated products that addressed only tsunami flooding depth. The study documented in this report was originally conceived as a follow-on that...

Subduction faults, called megathrusts, can generate large and hazardous earthquakes. The mode of slip and seismicity of a megathrust is controlled by the structural complexity of the fault zone. However, the relative strength of a megathrust based on the mode of slip is far from clear. The fault strength affects surface heat flow by frictional heat...

This paper explores the size and arrival of tsunamis in Oregon and Washington from the most likely partial ruptures of the Cascadia subduction zone (CSZ) in order to determine (1) how quickly tsunami height declines away from sources, (2) evacuation time before significant inundation, and (3) extent of felt shaking that would trigger evacuation. Ac...

Ocean drilling data show that the large trench-breaching rupture of the 2011 Tohoku-Oki earthquake occurred along a thin and weak fault zone.

Characterizations of tsunami hazards along the Cascadia subduction zone hinge on uncertainties in megathrust rupture models used for simulating tsunami inundation. To explore these uncertainties, we constructed 15 megathrust earthquake scenarios using rupture models that supply the initial conditions for tsunami simulations at Bandon, Oregon. Tsuna...

This digital data release is for seven tsunami inundation scenarios for the entire Oregon coast in the form of polygons (Esri ArcGIS® shapefiles). These scenarios are depicted on published Oregon Department of Geology and Mineral Industries (DOGAMI) tsunami inundation maps (TIM series). The hydrodynamic computer model SELFE is used to simulate tsun...

This digital data release is for seven tsunami inundation scenarios for the entire Oregon coast in the form of polygons (Esri ArcGIS® shapefiles). These scenarios are depicted on published Oregon Department of Geology and Mineral Industries (DOGAMI) tsunami inundation maps (TIM series). The hydrodynamic computer model SELFE is used to simulate tsun...

This digital data release is for seven tsunami inundation scenarios for the entire Oregon coast in the form of polygons (Esri ArcGIS® shapefiles). These scenarios are depicted on published Oregon Department of Geology and Mineral Industries (DOGAMI) tsunami inundation maps (TIM series). The hydrodynamic computer model SELFE is used to simulate tsun...

This digital data release is for seven tsunami inundation scenarios for the entire Oregon coast in the form of polygons (Esri ArcGIS® shapefiles). These scenarios are depicted on published Oregon Department of Geology and Mineral Industries (DOGAMI) tsunami inundation maps (TIM series). The hydrodynamic computer model SELFE is used to simulate tsun...

This digital data release is for seven tsunami inundation scenarios for the entire Oregon coast in the form of polygons (Esri ArcGIS® shapefiles). These scenarios are depicted on published Oregon Department of Geology and Mineral Industries (DOGAMI) tsunami inundation maps (TIM series). The hydrodynamic computer model SELFE is used to simulate tsun...

This digital data release is for seven tsunami inundation scenarios for the entire Oregon coast in the form of polygons (Esri ArcGIS® shapefiles). These scenarios are depicted on published Oregon Department of Geology and Mineral Industries (DOGAMI) tsunami inundation maps (TIM series). The hydrodynamic computer model SELFE is used to simulate tsun...

Coastal stratigraphy from the Pacific Northwest of the United States contains evidence of sudden subsidence during ruptures of the Cascadia subduction zone. Transfer functions (empirical relationships between assemblages and elevation) can convert microfossil data into coastal subsidence estimates. Coseismic deformation models use the subsidence va...

At 8:04 P.M. Pacific daylight time (PDT) on 27 October 2012 (03:04 universal time (UT), 28 October), Canada's second largest instrumentally recorded earthquake rocked Haida Gwaii (formerly Queen Charlotte Islands) and the mainland coast of British Columbia. The M 7.7 event off the west coast of Moresby Island caused a tsunami with local runup of mo...

[1] Past earthquake rupture models used to explain paleoseismic estimates of coastal subsidence during the great A.D. 1700 Cascadia earthquake have assumed a uniform slip distribution along the megathrust. Here we infer heterogeneous slip for the Cascadia margin in A.D. 1700 that is analogous to slip distributions during instrumentally recorded gre...

The Makran subduction zone experienced a tsunamigenic Mw 8.1 earthquake in 1945 and recent, smaller earthquakes also suggest seismicity on the megathrust; however, its historical record is limited and hazard potential enigmatic. We have developed a 2-D thermal model of the subduction zone. The results are twofold: (1) The thick sediment cover on th...

With new data recovered in December 2011 and November 2012 from two Ocean Drilling Program (ODP) CORK (circulation obviation retrofit kit) borehole observatories in the toe of the Nankai subduction zone accretionary prism (Hole 808I) and in the subducting Philippine Sea plate (Hole 1173B) off Southwestern Japan, records of formation fluid pressure...

Numerous earthquakes have occurred at subduction zones in the past 5 years, and some were devastating. Kelin Wang describes what we have learned about the seismicity of the shallow zone.

Among the wide range of thermal, petrologic, hydrological, and structural factors that potentially affect subduction earthquakes, the roughness of the subducting seafloor is among the most important. By reviewing seismic and geodetic studies of megathrust locking/creeping state, we find that creeping is the predominant mode of subduction in areas o...

This digital data release is for seven tsunami inundation scenarios for the entire Oregon coast in the form of polygons (Esri ArcGIS® shapefiles). These scenarios are depicted on published Oregon Department of Geology and Mineral Industries (DOGAMI) tsunami inundation maps (TIM series). The hydrodynamic computer model SELFE is used to simulate tsun...

We test hypothetical tsunami scenarios against a 4,600-year record of sandy deposits in a southern Oregon coastal lake that offer minimum inundation limits for prehistoric Cascadia tsunamis. Tsunami simulations constrain coseismic slip estimates for the southern Cascadia megathrust and contrast with slip deficits implied by earthquake recurrence in...

Decadal-scale postseismic deformation of subduction earthquakes has been widely modeled using a Maxwell viscoelastic Earth with a mantle-wedge viscosity of about 1019 Pa s. Short-term postseismic deformation within a few years after the earthquake remains a more challenging problem because of the predominance of afterslip of the megathrust and the...

Subduction zones produce the largest earthquakes. Over the past two decades, space geodesy has revolutionized our view of crustal deformation between consecutive earthquakes. The short time span of modern measurements necessitates comparative studies of subduction zones that are at different stages of the deformation cycle. Piecing together geodeti...

The behaviour of along-strike propagation was recognized in the first report of the discovery of Cascadia slow slip [Dragert et al., 2001]. Even with very few and sparsely distributed GPS stations, it could be estimated that the slow slip in 1999 propagated in the northwest direction at ~6 km/day. It was later established that the occurrence of tre...

Abrupt coastal subsidence induced by the great AD 1700 Cascadia earthquake has been estimated from paleoseismic evidence of buried soils and overlying mud and associated tsunamis deposits. These records have been modeled using a rather uniform rupture model, a mirror image of the uniform interseismic fault locking based on modern GPS observations....

Recent magnitude-9 (M9) earthquakes at subduction zones in Sumatra and Japan are focusing research efforts to learn the history of these infrequent earthquakes at other subduction zones worldwide. We estimate the magnitude of prehistoric earthquakes at the Cascadia subduction zone by comparing elevation-sensitive ecologic communities of modern inte...

Episodic tremor and slip (ETS) have now been observed along the northern Cascadia margin for over 15 years. Recent densification of GPS coverage and the introduction of Gladwin borehole strainmeters (BSMs) under the Plate Boundary Observatory have enabled the derivation of improved slip models and have allowed more detailed monitoring of the migrat...

Of the 3 great earthquakes to have occurred in the GPS observational era, the proximity to Andes of the 2010 Maule event offers the most promise in relating subduction-zone forcing to active orogenic process. In particular, the backarc in this part of the Andes is unique because Quaternary fold and thrust belt shortening rates are almost negligible...

The Mw = 9.0 earthquake of 11 March 2011 at the Japan Trench and its devastating tsunami underscore the importance of understanding seismogenic behavior of subduction faults and realistically estimating the potential size of future earthquakes and tsunamis. For the Cascadia subduction zone (Figure 1a), a critical knowledge gap is the level of micro...

Detailed heat flow surveys were carried out in the central part of the Nankai Trough southeast of the Kii Peninsula (off Kumano) for investigation of the thermal structure of the subducting plate interface. At stations in the Kumano Trough (forearc basin) and its vicinity, long-term monitoring of temperature profiles in surface sediments was conduc...

Seamount subduction is a common process in subduction zone tectonics. Contradicting a widely held expectation that subducting seamounts generate large earthquakes, seamounts subduct largely aseismically, producing numerous small earthquakes. On rare occasions when they do produce relatively large events, the ruptures tend to be complex, suggesting...

In the forearc mantle wedge, the thermal field depends strongly on slab-driven mantle wedge flow. The flow is in turn affected by the thermal field via the temperature dependence of mantle rheology. Using thermal modeling, we show that the nonlinear feedback between the thermal and flow fields always leads to complete stagnation of the mantle wedge...

Slow slip events, or “silent” earthquakes, may relieve a significant amount of stress at many subduction plate boundaries, both downdip of the limit of seismogenesis, and within the seismogenic zone itself in cases where seismic energy release accounts for only a fraction of the plate tectonic displacement rate (Schwartz and Rokosky, 2007). Slow sl...

Geological evidence for sudden coastal subsidence along the west coast of southern Vancouver Island points to the occurrence of great prehistorical subduction earthquakes. Contemporary uplift and crustal shortening patterns in southern Vancouver Island appear to indicate that the subduction megathrust fault is currently locked. To understand better...

We develop 15 full-margin rupture models for Cascadia subduction zone earthquakes that define vertical seafloor deformation used to simulate tsunami inundation at Bandon, Oregon. Rupture models include slip partitioned to a splay fault in the accretionary wedge and models that vary the updip limit of slip on a buried megathrust fault. Coseismic sli...

The monitoring of subduction zone Episodic Tremor and Slip (ETS) has been carried out primarily using seismic data for tremor and continuous Global Positioning System (GPS) and strain- or tilt-meter observations for transient slip. The regularity of ETS episodes in the forearc of the northern Cascadia Subduction Zone has recently allowed us to sche...

The wealth of GPS data recorded during and after the Maule earthquake allows us to test numerical models of co- and post-seismic deformation. We develop spherical-earth finite element models invoking bi-viscous viscoelastic stress relaxation and kinematically prescribed afterslip. For coseismic deformation, only elastic moduli are relevant: the You...

The southern Andes associated with the 2010 and 1960 megathrust earthquakes are characterized by a narrow cordillera, relatively low elevations ( 4000 m), large amounts of Neogene crustal shortening, and andesitic-dacitic stratovolcanoes and ignimbrite complexes that are restricted to the arc. Furthermore, in contrast to the currently active fold a...