Earthquake Report: M 7.5 Venezuela

I have been quite busy doing some fault trenching in northern California (in the region of the Mendocino triple junction) and have been at a few workshops and meetings. SO, I have been trying to catch up on these Earthquake Reports.

In June 2026, while I was getting mud beneath my fingernails in the trench, there was a pair of earthquakes in northern Venezuela. These earthquakes happened less than a minute apart! 33 seconds to be more precise. It must have been quite frightening to experience that! (I have been in an M 7.2 earthquake but a M 7.5 earthquake is much larger!) The M 7.5 hit while the shaking from the M 7.2 was still happening.

    In the order of occurrence:

  1. 2026.06.24 22:04:31 (UTC) M 7.2
  2. 2026.06.24 22:05:04 (UTC) M 7.5

The tectonics from this part of the world is dominated by a strike-slip plate boundary, where the Caribbean plate moves East relative to the South America plate.

This right-lateral strike-slip plate boundary fault (right-lateral because, when looking across the fault, the plate on the other side of the fault moves to the right) has had many smaller sized strike-slip faults in the past century.

Many of them in the M 6 range.= but there were some M 7-7.3 earthquakes in 1997 and 2018

The Earthquake Engineering Research Institute has an Earthquake Clearinghouse website online with some materials about this earthquake. EERI and other organizations often send teams to regions following large earthquakes and tsunami to document the damage. They mostly look for how these earthquakes and tsunami damage the built environment. See the section below for links to EERI resources.

There was a small tsunami generated by this earthquake sequence. However, the only tide gage online has a small tsunami record as the gage is at a large distance from the earthquake.

I will review the tectonic setting below the interpretive poster. Please look at the social media posts to learn more about this earthquake as these observations were presented in a real time learning event.

Below is my interpretive poster for this earthquake

  • I plot the seismicity from the past month, with diameter representing magnitude (see legend). I include earthquake epicenters from 1925-2025 with magnitudes M ≥ 3.0 in one version.
  • I plot the USGS fault plane solutions (moment tensors in blue and focal mechanisms in orange), possibly in addition to some relevant historic earthquakes.
  • A review of the basic base map variations and data that I use for the interpretive posters can be found on the Earthquake Reports page. I have improved these posters over time and some of this background information applies to the older posters.
  • Some basic fundamentals of earthquake geology and plate tectonics can be found on the Earthquake Plate Tectonic Fundamentals page.

    I include some inset figures. Some of the same figures are located in different places on the larger scale map below.

  • In the lower right corner is a map showing plate boundary fault lines and the major tectonic plates. The M 7.5 location is shown as a red circle.
  • Above the tectonic overview map is a view of the USGS finite fault slip model. This shows the amount that they estimate that the fault slipped during the earthquake. The fault may have slipped more than 2.5 meters. I placed an overlay of this fault slip on the main map.
  • In the lower left are maps that show earthquake intensity for each earthquake using the Modified Mercalli Intensity (MMI) Scale.
  • To the right of these maps is a plot that shows the same intensity for the M 7.5 (both modeled and reported) data as displayed on the map. Note how the intensity gets smaller with distance from the earthquake. I label some of the large cities, some are shown on the maps.
  • In the upper left corner are two maps showing the possibility of earthquake triggered landslides and earthquake induced liquefaction for these two earthquakes, a map pair for each earthquake. Read more about these maps later in the report.
  • In the upper right corner are two additional maps that show more about the tectonic plate boundary fault systems. I place a yellow star in the location of the M 7.5 epicenter. The map on the right shows earthquake mechanisms in the region (informing us about what type of plate boundaries these are). The map on the left shows us how the plates are moving relative to each other (using a science called “geodesy”). We will see these maps in greater detail later in the report.
  • Here is the map with 6 week’s seismicity plotted.


Other Report Pages

Shaking Intensity

  • Here is a figure that shows a more detailed comparison between the modeled intensity and the reported intensity. Both data use the same color scale, the Modified Mercalli Intensity Scale (MMI). More about this can be found here. The colors and contours on the map are results from the USGS modeled intensity. The DYFI data are plotted as colored dots (color = MMI, diameter = number of reports).
  • In the upper panel is the USGS Did You Feel It reports map, showing reports as colored dots using the MMI color scale. Underlain on this map are colored areas showing the USGS modeled estimate for shaking intensity (MMI scale).
  • In the lower panel is a plot showing MMI intensity (vertical axis) relative to distance from the earthquake (horizontal axis). The models are represented by the green and orange lines. The DYFI data are plotted as light blue dots. The mean and median (different types of “average”) are plotted as orange and purple dots. Note how well the reports fit the green line (the model that represents how MMI works based on quakes in California).
  • Below the map and the lower plot is the USGS MMI Intensity scale, which lists the level of damage for each level of intensity, along with approximate measures of how strongly the ground shakes at these intensities, showing levels in acceleration (Peak Ground Acceleration, PGA) and velocity (Peak Ground Velocity, PGV).
  • Note the high intensity for the M 7.5, with DYFI observations approaching MMI 9! This must have been terrifying!


Potential for Ground Failure

  • Below are a series of maps that show the potential for landslides and liquefaction. These are all USGS data products.
    There are many different ways in which a landslide can be triggered. The first order relations behind slope failure (landslides) is that the “resisting” forces that are preventing slope failure (e.g. the strength of the bedrock or soil) are overcome by the “driving” forces that are pushing this land downwards (e.g. gravity). The ratio of resisting forces to driving forces is called the Factor of Safety (FOS). We can write this ratio like this:

    FOS = Resisting Force / Driving Force

  • When FOS > 1, the slope is stable and when FOS < 1, the slope fails and we get a landslide. The illustration below shows these relations. Note how the slope angle α can take part in this ratio (the steeper the slope, the greater impact of the mass of the slope can contribute to driving forces). The real world is more complicated than the simplified illustration below.


  • Landslide ground shaking can change the Factor of Safety in several ways that might increase the driving force or decrease the resisting force. Keefer (1984) studied a global data set of earthquake triggered landslides and found that larger earthquakes trigger larger and more numerous landslides across a larger area than do smaller earthquakes. Earthquakes can cause landslides because the seismic waves can cause the driving force to increase (the earthquake motions can “push” the land downwards), leading to a landslide. In addition, ground shaking can change the strength of these earth materials (a form of resisting force) with a process called liquefaction.
  • Sediment or soil strength is based upon the ability for sediment particles to push against each other without moving. This is a combination of friction and the forces exerted between these particles. This is loosely what we call the “angle of internal friction.” Liquefaction is a process by which pore pressure increases cause water to push out against the sediment particles so that they are no longer touching.
  • An analogy that some may be familiar with relates to a visit to the beach. When one is walking on the wet sand near the shoreline, the sand may hold the weight of our body generally pretty well. However, if we stop and vibrate our feet back and forth, this causes pore pressure to increase and we sink into the sand as the sand liquefies. Or, at least our feet sink into the sand.
  • Below is a diagram showing how an increase in pore pressure can push against the sediment particles so that they are not touching any more. This allows the particles to move around and this is why our feet sink in the sand in the analogy above. This is also what changes the strength of earth materials such that a landslide can be triggered.


  • Here Dr. Bohon demonstrates the phenomena of liquefaction.
    • @drwendyrocksit #Liquefaction is a process by which water-saturated sediment temporarily loses strength and acts as a fluid. This can happen during #earthquake shaking. #geophysics #geology ♬ Quicksand – Hatchie

  • And, another video demonstration.

  • Below is a diagram based upon a publication designed to educate the public about landslides and the processes that trigger them (USGS, 2004). Additional background information about landslide types can be found in Highland et al. (2008). There was a variety of landslide types that can be observed surrounding the earthquake region. So, this illustration can help people when they observing the landscape response to the earthquake whether they are using aerial imagery, photos in newspaper or website articles, or videos on social media. Will you be able to locate a landslide scarp or the toe of a landslide? This figure shows a rotational landslide, one where the land rotates along a curvilinear failure surface.


  • Below is the liquefaction susceptibility and landslide probability map (Jessee et al., 2017; Zhu et al., 2017) for each earthquake (M 7.2 on top and M 7.5 on bottom). Please head over to that report for more information about the USGS Ground Failure products (landslides and liquefaction). Basically, earthquakes shake the ground and this ground shaking can cause landslides.
  • I use the same color scheme that the USGS uses on their website. Note how the areas that are more likely to have experienced earthquake induced liquefaction are in the valleys. Learn more about how the USGS prepares these model results here.


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Some Relevant Discussion and Figures

    • Here is the Casco et al. (2011) tectonic overview map.


      • Plate tectonic configuration of the Caribbean region showing the location of the study cases presented in this issue (numbers refer to papers, arranged as in the issue), and other important geological features of the region (compiled from several sources).

    • Here is the Audemard et al. (2006) tectonic overview map.


      • Schematic map of Quaternary faults of Venezuela (simplified from Audemard et al. 2000). Faults and toponyms used throughout this contribution are identified.

    • Here is the Audemard et al. (2006) cross section showing the relations between the different subduction zones in the region.


      • The orogenic float model applied to the Mérida Andes. Cross-section extends from the northwestern tip of the Santa Marta Block (SMB; location in Fig. 2) to the Llanos Basin, across the southernmost Mérida Andes, at the Pamplona indenter. Bottom figure displays major geologic units and structures, whereas top figure only exhibits major structures -brittle thrust and strike-slip faults, detachments and triangle zones- to give a more legible view of their interplays.

    • Here are some cross sections showing the El Pilar fault, along with some of the thrust faults in the region (Jouanne et al., 2011). Section B is just to the west of where this M 7.3 earthquake happened.


      • Simplified sections across the southeastern Caribbean margin (based on maps and sections by Bellizzia et al. (1976), Stéphan et al. (1980), Campos (1981), Beck (1986), Chevalier (1987); locations in Fig. 1).

    • Here is the Audemard et al. (2006) map showing the major faults in northern Venezuela.


      • Map of Quaternary faults of Venezuela (after Audemard et al. 2000). Also accessible as a pdf file from the USGS web page in open file reports (ofr-00-0018). Line thickness is proportional to fault slip rate: the thickest indicates > 5 mm/a and the thinnest < 1mm/a. Shown faults have proven Quaternary activity.

    • Here is the Pindell and Kennan (2009) map.


      • Present day tectonic map of the Caribbean region.

    • Here is the Pindell and Kennan (2009) figure that shows how the large strike-slip plate boundary on the north side of Venezuela grew from the west over time.


      • Motion histories of: North (NA) and South America (SA) relative to Indo-Atlantic hot spot (IAHS) Mu¨ller et al. (1993) reference frame (grey lines; NA wrt IAHS and SA wrt IAHS); hot spots relative to North America (dashed black line; IAHS wrt NA); Caribbean relative to North America (heaviest black line; Car wrt NA), as summarized from former relative positions of the Caribbean Trench (lighter black lines). Also shown: Cayman Trough (grey outline); Cenozoic convergence between the Americas (inset upper right; P88 ¼ Pindell et al. 1988; M99 ¼ Mu¨ller et al. 1999); seismic tomographic profile of van der Hilst (1990) (inset, lower right).

    • Here is the Audemard (2000) map showing the many faults in this region.


      •

    Offshore Fault Studies

    • Colon et al. (2015) studied the 1900 M 7.6 earthquake offshore of northern Venezuela.
    • They used seismic reflection profiles for their work.
    • These maps show isoseismal contours (shaking intensity) for this earthquake.


      • Isoseismal maps for the October 1900 earthquake: A) Centeno-Gr€a (1949); B) Fiedler (1961); C) Jacubowicz and Larotta (1974); and D) Lugo (1984). The 3 first maps place the macroseismic epicenter of this event offshore northcentral Venezuela, while Lugo (1984) pulls it to shore.

    • Here is map showing the tectonic setting


      • Simplified geodynamic framework of Northern South America (modified from Audemard et al., 2000), where the alleged La Tortuga fault trace has been incorporated. Abbreviations: BF Bocono fault; EPF El Pilar fault; LBF Los Bajos-El Soldado fault system; LTF La Tortuga fault; OAF Oca-Anc  on fault system (also named Oca-Chirinos fault by Schubert and Krause, 1984; but with a different fault trace); SSF San Sebastian fault; WSF Warm Spring fault of Trinidad.

    • Here is map showing the faults and seismic profile locations.


      • Regional interpretation of faulting along the Northecentral Venezuelan coast, from acoustic reflection profiles (simplified from Schubert and Krause, 1984). Legend: a. strikeslip fault; b. direction of dip of fault plane in seismic line; c. inferred connection between faults in profiles; d. fault zones; e. epicenter of earthquake (5.5  M  7.2) f. epicenter of earthquake (4.5  M  5.4); g. basin; h. area of uplift. Abbreviations: AF Avila fault; BB Bonaire basin; BF Bocon  o fault; BRF Bruscas fault; CB Cariaco basin; EPFZ El Pilar fault zone; LVFZ La Victoria fault zone; MAF Macuto fault; MF Moron fault; O-CFZ Oca-Chirinos fault zone; TAF T   acata fault zone; TFZ Tacagua fault zone. Seismic lines shown in Fig. 4 are in bold line.

    • Here is map showing the faults and seismic profile locations.


      • Regional interpretation of faulting along the Northecentral Venezuelan coast, from acoustic reflection profiles (simplified from Schubert and Krause, 1984). Legend: a. strikeslip fault; b. direction of dip of fault plane in seismic line; c. inferred connection between faults in profiles; d. fault zones; e. epicenter of earthquake (5.5  M  7.2) f. epicenter of earthquake (4.5  M  5.4); g. basin; h. area of uplift. Abbreviations: AF Avila fault; BB Bonaire basin; BF Bocon  o fault; BRF Bruscas fault; CB Cariaco basin; EPFZ El Pilar fault zone; LVFZ La Victoria fault zone; MAF Macuto fault; MF Moron fault; O-CFZ Oca-Chirinos fault zone; TAF T   acata fault zone; TFZ Tacagua fault zone. Seismic lines shown in Fig. 4 are in bold line.

    • Here is map showing the faults and seismic profile locations used in their study.


      • Location map of high resolution shallow seismic profiles acquired in September-October 2007 during the Vargas (VARS) and Littoral (LIT) campaigns by a joint international effort (FUNVISIS-ISTerre-RCMG). The lines used in this contribution are highlighted as thick lines and labeled by the figure number accordingly. Geologic base map by Hackley et al. (2005). Color code of geologic units complies with the international nomenclature. Map of Quaternary faults taken from Audemard et al. (2000). Note that the LTF submarine trace is inferred from Cabo Codera longitude towards the west. In addition, this interpretation does not consider the LTF as the prolongation of the Oca-Ancon fault system. This  figure also provides the location of seismic lines displayed in this study from previous surveys (Schubert, 1982; Schubert and Krause, 1984 and Paolini, 2012).

    • Here is the seismic profile across the San Sebastian fault (figure 10 on the above map).


      • Uninterpreted (top) and interpreted (bottom) sparker profile (VARS 12). For relative location, refer to Fig. 5. The SSF appears as a very sharp single vertical fault plane, conversely to the structural style exhibited west of Maiquetía. This visualization is possible because the coast has a large embayment at Chuspa, several kilometers west of Cabo Codera (easternmost tip of the Coastal range), allowing the vessel crossing across. Note the freshness and preservation of the north-facing fault scarp in unconsolidated sediments. Interpretation is only provided above first multiple.

    • Here is the seismic profile across the San Sebastian fault (figure 11 on the above map).


      • Uninterpreted (top) and interpreted (bottom) high-resolution shallow seismic line VARS 16. Relative location is given in Fig. 5. The SSF appears as a single vertical fault plane at the edge of a narrow elevated platform, looking much alike to a fault bench. Also note the protruding “basement” through a younger onlapping sedimentary package to the right of the profile. Interpretation is only provided above first multiple.

    • Here is the seismic profile across the San Sebastian fault (figure 12 on the above map).


      • Uninterpreted (top) and interpreted (bottom) profile VARS 18. Refer to Fig. 5 for relative location. The sub-vertical SSF runs at the edge of a narrow elevated bench, much in the same way as shown in line VARS 16 (compare to Fig. 11), located 11 km east of VARS 18. Interpretation is only provided above first multiple.

    • This is an illustration showing their interpretation of the faults offshore of Venezuela.


      • election of simplified line-drawings from north-south trending acoustic reflection profiles of the Cariaco basin and adjacent shelves, compiled by Schubert (1982). Inset figure provides relative location of profiles (from Schubert, 1982). Relative location to other surveys is provided in Fig. 5. Numbers in line 13 are water depths. Vertical scale is variable between profiles. Compare lines 1, 2 and 8 from this figure to our VARS 16 (Fig. 11), 14 (Fig. 15) and 1 (Fig. 14) sparker lines. The Moron Fault Zone  eMFZ-identified in these profiles corresponds to LTF of Beltraan (1993). The latter one is the definition adopted in this work. EPFZ stands for El Pilar Fault Zone.

    Onshore Fault Studies

    • Beltran et al. (2017) developed slip rates for strike-slip faults in northwestern Venezuela.
    • This map highlights where their study from 2017 is.


      • Geodynamic context of Venezuela. The North Andean Block (in yellow) composed of minor blocks accommodates part of the relative displacement between the South American, Nazca, and Caribbean plates. The Boconó fault is represented in red. This figure is based on Trenkamp et al. [2002], DeMets et al. [2010], Egbue and Kellogg [2010], and Monod et al. [2010].

    • This map shows existing slip rates and historic seismicity (Beltran et al., 2017).


      • (a) Seismotectonic map of Venezuela: mapping of faults is based on Audemard et al. [2000], geodetic velocity is based on DeMets et al. [2010], and seismicity data are provided by the Advanced National Seismic System’s comprehensive earthquake catalog (ANSS ComCat) [U.S.Geological Survey, 2017]. CLF: Colombian Llanos Foothills, CRF: Central Range Fault, EPF: El Pilar Fault, OAF: Ocá-Ancon Fault, SMBF: Santa Marta-Bucaramanga Fault, and SSF: San Sebastian Fault. (b) Seismotectonic map of western Venezuela, the fault slip rates come from Late Quaternary studies recompiled in Audemard et al. [2000]. The Boconó fault crosscuts the Venezuelan Andes and is divided into five segments [Audemard et al., 2000]. The red star represents the supposed epicenter of the 1812 historical earthquake [Choy et al., 2010]. Arrows display GPS velocities reported by University NAVSTAR Consortium (UNAVCO) [2017] relative to a stable South American plate. The dashed square is the location of Figure 3.

    • This map shows existing slip rates in the region of their study (Beltran et al., 2017).


      • (Seismotectonic context of the Yaracuy Valley. Fault mapping is based on Audemard et al. [2000]. The thick line represents the Boconó fault defined in Audemard [2016]: the blue portion is the Triste-Albarico segment, the white portion is the Albarico-La Virgen segment, and the green portion is the La Virgen-Yaritagua segment. The orange dashed line is IX intensity contour for the 1812 event drawn by Grases [1980]. Dots represent instrumental seismicity provided by FUNVISIS and by International Seismological Centre [2013]. The dashed rectangle represents Figure S2.

    • This map shows historical earthquake rupture extents in the region of their 2018 Bocono fault study (Beltran et al., 2018).


      • A) Geodynamic context of Venezuela. The North Andean Block (in yellow), composed of minor blocks, accommodates part of the relative displacement between the South American, Nazca and Caribbean plates. The Boconó Fault is shown in red, SSF is the San-Sebastian Fault. This figure is based on Trenkamp et al. (2002), DeMets et al. (2010), Egbue and Kellogg (2010) and Monod et al. (2010). B) Quaternary slip rates of the Boconó Fault (Pousse-Beltran et al., 2017). The color lines highlight the five segments of the fault based on Audemard et al. (2000). The slip rate references quoted are: [a] Wesnousky et al. (2012), [b] Wesnousky et al. (2012) and Carcaillet et al. (2013), [c] Giegengack et al. (1976) and Egbue and Kellogg (2010), [d] Audemard et al. (1999); [e] Soulas (1986), [f] Audemard (1997), [g] Singer and Beltran (1996). C) Spatio-temporal distribution of the historical seismicity and location of the trench sites carried out along the Boconó Fault (modified after Audemard (2014)). This figure summarizes the fault segment characteristics: historical events, trench sites, number of events dated in the trenches and return period. References are for the “Mis Delirios” and “La Grita” trenches: Audemard (1997, 1998), for the “Quinanoque” and “Pantaleta” trenches: Alvarado et al. (2008), for the “Morro de los Hoyos” trench is Audemard et al. (1999), for the “Mesa del Caballo” trench is Audemard et al. (2008), for the “La Primavera” and “Los Manzanos” trenches is: Audemard (2008), for the “Buena Vista” trench is Beltran et al. (1990), and finally for the “Quigua” and “Yaritagua” trenches is Audemard (2016). See Fig. S1 in the supplementary material for the detailed chronology of the events dated in the trenches.

    • This map shows additional historical earthquake rupture extents in the region of their 2018 Bocono fault study (Beltran et al., 2018) along with shaking contours from an 1812 earthquake.


      • A) Sub-events and epicenters associated with the 1812 event. The yellow line marked as 1812a corresponds to the rupture inferred along the Boc-e segment which destroyed the cities of Barquisimeto and San Felipe. The yellow line demarcated as 1812b corresponds to the rupture along the San Sebastian Fault which destroyed Caracas. The yellow dot denoted as 1812c in the right top frame is the localized event that occurred near the city of Merida (Choy et al., 2010). The dotted yellow line represents the possible rupture between the 1812a and 1812b events in the case of a continuous rupture. The ruptures and epicenters of the 1900 and 1967 events are drawn following Audemard (2002), Choy et al. (2010) and Colón et al. (2015). The fault mapping is based on Audemard et al. (2000). B) Seismo-tectonic context of the Yaracuy Valley. The stars represent cities where an earthquake has been reported since 1802, the filled purple stars correspond to cities where the 1812 event was felt most strongly (Casas-Sainz, 1991; Choy et al., 2010). The purple lines represent isoseismal contours extrapolated from the intensity reported in the cities (stars on the map) in 1812 and the isoseismal map in Altez (2016). The dots represent the instrumental seismicity recorder by FUNVISIS and the International Seismological Center (2013) between 1978 and 2014. The blue and white triangle indicates the trench site studied in this contribution.

    Geodesy

    Geodesy is the study of how the Earth deforms with time. As plates move relative to each other, we can measure this motion.

    There are many modern ways of measuring this motion. Originally, we measured the distances between fixed locations like benchmarks embedded into the ground. As these benchmarks moved, the distances between them changed.

    We used to measure the distances with chains or tape measures. Later we used measurements using satellite observations (e.g, GPS or GNSS observations). Lately we have been using other forms of satellite measurements called InSAR (short for interferrometric synthetic aperture radar). Some of the social media posts below show InSAR analyses that measure the displacement of the plates that moved during the earthquake.

    SO, there are geodetic measurements of long term plate motion (e.g., between earthquakes, called the interseismic period) or for the period from during the earthquake motion (called the coseismic period).

    • This is a map from Reinoza et al. (2015) where they present their geodetic analysis (analysis of the deformation of the earth). These authors use GPS data to evaluate the potential activity of the El Pilar fault.


      • Location map of the active faults in northeastern Venezuela [Audemard et al., 2000] showing distribution of the GNSS stations: yellow squares, green circles, and red triangles are GNSS sites on which the acquisition campaigns were carried out in 2003, 2005, and 2013 respectively; the blue star corresponds to the cGNSS CUMA station of REMOS-IGVSB Network. We show the epicenter location of 1929 and 1997 events with their respective proposed ruptures (orange lines) [Audemard, 2007]. (top right) The inset box shows a schematic geodynamic map of the southeastern Caribbean [Audemard, 1999b; Audemard et al., 2000; Weber et al., 2001]. Legend: BF = Boconó Fault, EPF = El Pilar Fault, OAF = Oca Ancón fault, SMBF = Santa Marta Bucaramanga Fault, and SSF = San Sebastian Fault.

    • Here are the GPS data. The white arrows (vectors) show the observed velocities (motion rate) for the GPS sites shown on the previous map. The black arrows (vectors) show how their model results compare with the observational data.


      • Observed velocities (white arrows) with error ellipses for 66% confidence level and simulated velocities (black arrows) according to the upgrade of displacement-simulation method. All displacements are based on the South America reference frame.

    • These plate motion vectors show the GPS velocities at sites across the Caribbean (Symithe et al., 2015).
    • The top map shows GPS velocities relative to the North America plate and the bottom map shows velocities relative to the South America plate.


      • (top) GPS velocities used in the model shown with respect to the North American plate defined by the velocity of 25 GPS sites located in the stable interior of the plate [Calais et al., 2006]. (bottom) GPS velocities shown with respect to the Caribbean plate as defined in the best fit block model described in the text. Error ellipses are 95% confidence. Blue arrows show GPS velocities from Pérez et al. [2001] in Venezuela because of their large uncertainty and the lack of common sites with our solution, which prevents us from rigorously combining them to our solution. They are not used in the model but used to show that they are consistent with the rest of the velocity field.

    • This map shows the relative motion at modeled locations along the plate boundary faults (based on how they modeled tectonic block motion across the region).


      • Best fit model geometry with block boundaries as solid black lines and predicted relative block motions as arrows with velocity indicated in mm/yr with their 95% confidence ellipse according to the parameters listed in Table 2. Red = strike slip (i.e., slip direction with ±30o from fault strike), blue = reverse or transpressional, green = normal of transtensional. Residual velocities are shown with grey arrows. We omitted their error ellipses for a sake of readability, see Figures 9 and 10 for a close up view on Hispaniola and the Lesser Antilles. The thin dashed line indicates the boundary of the Bahamas Platform.

    Seismic Hazard and Seismic Risk

    • These are the two maps that show seismic hazard and seismic risk, the GEM Seismic Hazard and the GEM Seismic Risk maps from Pagani et al. (2018) and Silva et al. (2018).

      • The GEM Seismic Hazard Map:




      • The Global Earthquake Model (GEM) Global Seismic Hazard Map (version 2018.1) depicts the geographic distribution of the Peak Ground Acceleration (PGA) with a 10% probability of being exceeded in 50 years, computed for reference rock conditions (shear wave velocity, VS30, of 760-800 m/s). The map was created by collating maps computed using national and regional probabilistic seismic hazard models developed by various institutions and projects, and by GEM Foundation scientists. The OpenQuake engine, an open-source seismic hazard and risk calculation software developed principally by the GEM Foundation, was used to calculate the hazard values. A smoothing methodology was applied to homogenise hazard values along the model borders. The map is based on a database of hazard models described using the OpenQuake engine data format (NRML). Due to possible model limitations, regions portrayed with low hazard may still experience potentially damaging earthquakes.

      • The GEM Seismic Risk Map:




      • The Global Seismic Risk Map (v2018.1) presents the geographic distribution of average annual loss (USD) normalised by the average construction costs of the respective country (USD/m2) due to ground shaking in the residential, commercial and industrial building stock, considering contents, structural and non-structural components. The normalised metric allows a direct comparison of the risk between countries with widely different construction costs. It does not consider the effects of tsunamis, liquefaction, landslides, and fires following earthquakes. The loss estimates are from direct physical damage to buildings due to shaking, and thus damage to infrastructure or indirect losses due to business interruption are not included. The average annual losses are presented on a hexagonal grid, with a spacing of 0.30 x 0.34 decimal degrees (approximately 1,000 km2 at the equator). The average annual losses were computed using the event-based calculator of the OpenQuake engine, an open-source software for seismic hazard and risk analysis developed by the GEM Foundation. The seismic hazard, exposure and vulnerability models employed in these calculations were provided by national institutions, or developed within the scope of regional programs or bilateral collaborations.
      • Petersen et al. (2018) calculated the seismic hazard for South America. They prepared a suite of estimates of hazard calculated for different time periods and for different seismic periods (buildings of different height have different periods and respond to seismic shaking with shaking frequencies relative to their period).
      • Below is a series of three maps showing the chance of slight (or greater), moderate (or greater), and considerable (or greater) shaking over a period of 100 years.






        • Chance of (a) slight (MMI ≥ VI), (b) moderate (MMI ≥ VII), or (c) considerable (MMI ≥ VIII) damaging earthquake shaking in 100 yrs

      • Salgado-Gálvez et al. (2023) calculated seismic hazard for the Caribbean and Central America.
      • Below are three maps for this region.


        • Seismic hazard map for peak ground acceleration (PGA) (in g) on rock for a 475 yr return period.


        Seismic hazard map for spectral acceleration (SA) at 0.2 (in g) on rock for a 475 yr return period.


        . Seismic hazard map for PGA (in g) on soil for a 475 yr return period.

      Tsunami

      • Cazenave et al. have a preprint showing their submitted paper on the tsunami. This map shows the results from their modeling, color depicting the maximum tsunami amplitude.


        • Coastal gauges and the DART system that recorded the tsunami (red), possibly recorded the tsunami (orange), and did not record the tsunami (green). The background map shows the maximum simulated tsunami wave amplitudes for the USGS finite-fault model presented hereafter in section 2.2. A common, open-ended logarithmic colour scale was applied in order to highlight small amplitudes while showing larger amplitudes confined to the source region. White contours represent tsunami travel times (TTT) at 10 minute intervals.

      References:

      Basic & General References

    • Frisch, W., Meschede, M., Blakey, R., 2011. Plate Tectonics, Springer-Verlag, London, 213 pp.
    • Hayes, G., 2018, Slab2 – A Comprehensive Subduction Zone Geometry Model: U.S. Geological Survey data release, https://doi.org/10.5066/F7PV6JNV.
    • Holt, W. E., C. Kreemer, A. J. Haines, L. Estey, C. Meertens, G. Blewitt, and D. Lavallee (2005), Project helps constrain continental dynamics and seismic hazards, Eos Trans. AGU, 86(41), 383–387, , https://doi.org/10.1029/2005EO410002. /li>
    • Jessee, M.A.N., Hamburger, M. W., Allstadt, K., Wald, D. J., Robeson, S. M., Tanyas, H., et al. (2018). A global empirical model for near-real-time assessment of seismically induced landslides. Journal of Geophysical Research: Earth Surface, 123, 1835–1859. https://doi.org/10.1029/2017JF004494
    • Kreemer, C., J. Haines, W. Holt, G. Blewitt, and D. Lavallee (2000), On the determination of a global strain rate model, Geophys. J. Int., 52(10), 765–770.
    • Kreemer, C., W. E. Holt, and A. J. Haines (2003), An integrated global model of present-day plate motions and plate boundary deformation, Geophys. J. Int., 154(1), 8–34, , https://doi.org/10.1046/j.1365-246X.2003.01917.x.
    • Kreemer, C., G. Blewitt, E.C. Klein, 2014. A geodetic plate motion and Global Strain Rate Model in Geochemistry, Geophysics, Geosystems, v. 15, p. 3849-3889, https://doi.org/10.1002/2014GC005407.
    • Meyer, B., Saltus, R., Chulliat, a., 2017. EMAG2: Earth Magnetic Anomaly Grid (2-arc-minute resolution) Version 3. National Centers for Environmental Information, NOAA. Model. https://doi.org/10.7289/V5H70CVX
    • Müller, R.D., Sdrolias, M., Gaina, C. and Roest, W.R., 2008, Age spreading rates and spreading asymmetry of the world’s ocean crust in Geochemistry, Geophysics, Geosystems, 9, Q04006, https://doi.org/10.1029/2007GC001743
    • Pagani,M. , J. Garcia-Pelaez, R. Gee, K. Johnson, V. Poggi, R. Styron, G. Weatherill, M. Simionato, D. Viganò, L. Danciu, D. Monelli (2018). Global Earthquake Model (GEM) Seismic Hazard Map (version 2018.1 – December 2018), DOI: 10.13117/GEM-GLOBAL-SEISMIC-HAZARD-MAP-2018.1
    • Silva, V ., D Amo-Oduro, A Calderon, J Dabbeek, V Despotaki, L Martins, A Rao, M Simionato, D Viganò, C Yepes, A Acevedo, N Horspool, H Crowley, K Jaiswal, M Journeay, M Pittore, 2018. Global Earthquake Model (GEM) Seismic Risk Map (version 2018.1). https://doi.org/10.13117/GEM-GLOBAL-SEISMIC-RISK-MAP-2018.1
    • Storchak, D. A., D. Di Giacomo, I. Bondár, E. R. Engdahl, J. Harris, W. H. K. Lee, A. Villaseñor, and P. Bormann (2013), Public release of the ISC-GEM global instrumental earthquake catalogue (1900–2009), Seismol. Res. Lett., 84(5), 810–815, doi:10.1785/0220130034.
    • Zhu, J., Baise, L. G., Thompson, E. M., 2017, An Updated Geospatial Liquefaction Model for Global Application, Bulletin of the Seismological Society of America, 107, p 1365-1385, https://doi.org/0.1785/0120160198

      • Specific References

    • Audemard, F.A., Machette, M.N., Cox, J.W., Dart, R.L., and Haller, K.M., 2000. Map and Database of Quaternary Faults in Venezuela and its Offshore Regions, USGS Open File Report 00-018
    • Audemard M., F.A., Singer P., A., Soulas, J-P., and the Neotectonics Section of the Funvisis Earth Sciences Department, 2006. Quaternary Faults and Stress Regime of Venezuela in Rev. Asoc. Geol. Argent., vol. 61, no.4, https://revista.geologica.org.ar/raga/article/view/1217
    • Beltran, L.P. Vassallo, F. Audemard, F. Jouanne, J. Carcaillet, E. Pathier, and M. Volat (2017), Pleistocene slip rates on the Boconó fault along the North Andean Block plate boundary, Venezuela, Tectonics, 6, 1207–1231, http://dx.doi.org/10.1002/2016TC004305
    • Beltran, L.P., Vassallo, R., Audemard, F., Jouanne, F., Oropeza, J., Garambois, S., and Aray, J., 2018. Earthquake geology of the last millennium along the Boconó Fault, Venezuela in Tectonophysics, Volumes 747–748, p. 40-53, https://doi.org/10.1016/j.tecto.2018.09.010
    • Casco, A.G., Fernandez, J.A.P., Iturralde-Vinent, M.A., 2011. Subduction Zones of the Caribbean: the sedimentary, magmatic, metamorphic and ore-deposit records UNESCO/iugs igcp Project 546 Subduction Zones of the Caribbean in Vol. 9 No. 3-4 (2011): Subduction Zones of the Caribbean: The sedimentary, magmatic, metamorphic and ore-deposit records (UNESCO/IUGS IGCP), https://doi.org/10.1344/105.000001745
    • Cazenave, M., Jean Roger, Mélody Philippon, Franck Audemard, and Delouis, B., 2026. The tsunami triggered by the 24 June 2026 Venezuela earthquakes: tectonic context and tsunami modelling in Pure and Applied Geophysics, preprint https://doi.org/10.21203/rs.3.rs-10607566/v1
    • Colón, D., F.A. Audemard, C. Beck, J. Avila, C. Padrón, M. De Batist, M. Paolini, A.F. Leal, A. Van Welden, 2015. The 1900 Mw 7.6 earthquake offshore north–central Venezuela: Is La Tortuga or San Sebastián the source fault? in Marine and Petroleum Geology, vol. 67, p. 498-511, https://doi.org/10.1016/j.marpetgeo.2015.06.005.
    • Jouanne, F., Audemard, F.A., Beckm, C., Van Welden, A., Ollarves, R., and Reinoz, C., 2011. Present-day deformation along the El Pilar Fault in eastern Venezuela: Evidence of creep along a major transform boundary in Journal of Geodynamics, v. 51., p. 398-410, doi:10.1016/j.jog.2010.11.003
    • Meyer, B., Saltus, R., Chulliat, a., 2017. EMAG2: Earth Magnetic Anomaly Grid (2-arc-minute resolution) Version 3. National Centers for Environmental Information, NOAA. Model. doi:10.7289/V5H70CVX
    • Petersen, M.D., Stephen C. Harmsen, Kishor S. Jaiswal, Kenneth S. Rukstales, Nicolas Luco, Kathleen M. Haller, Charles S. Mueller, Allison M. Shumway; Seismic Hazard, Risk, and Design for South America in Bulletin of the Seismological Society of America, v. 108, no. 2, p. 781–800, https://doi.org/10.1785/0120170002
    • Pindell, J.L. and Kennan, L., 2009. Tectonic evolution of the Gulf of Mexico, Caribbean and northern South America in the mantle reference frame: an update in JAMES, K. H., LORENTE, M. A. & PINDELL, J. L. (eds) The Origin and Evolution of the Caribbean Plate. Geological Society, London, Special Publications, 328, 1–55.
      DOI: 10.1144/SP328.1
    • Reinoza, C., F. Jouanne, F. A. Audemard, M. Schmitz, and C. Beck (2015), Geodetic exploration of strain along the El Pilar Fault in northeastern Venezuela, J. Geophys. Res. Solid Earth, 120, 1993– 2013, doi:10.1002/2014JB011483.
    • algado-Gálvez, M. A., M. Ordaz, S. K. Singh, X. PérezCampos, B. Huerta, P. Bazzurro, and E. Fagà (2022). A Caribbean and Central America Seismic Hazard Model for Sovereign Parametric Insurance Coverage in BSSA, v. 113, p. 1–22, https://doi.org/10.1785/0120220117
    • Symithe, S., E. Calais, J. B. de Chabalier, R. Robertson, and M. Higgins, 2015. Current block motions and strain accumulation on active faults in the Caribbean, J. Geophys. Res. Solid Earth, v. 120, p. 3748–3774, http://dx.doi.org/10.1002/2014JB011779

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