WRITING
A couple of pieces and research that I have written over the years!
Pandemic continues to hit small business in Foggy Bottom
Ashley Gonales
President Joe Biden Orders Legislation on Gun Control
Ashley Gonzales
President Biden announced a package of executive actions to curb gun violence on April 8. (Annie Linskey)
President Joe Biden announced six legislation orders designed to advance gun safety laws in three communities in the wake of 159 mass shootings in the 2021 year alone in this country on April 8, 2021. Biden issued the six executive orders addressing gun violence, particularly on “ghost guns” and red flag laws.
Biden's new steps include a move to crack down on "ghost guns," homemade firearms that lack serial numbers used to trace them and are often purchased without a background check, to be treated as firearms under the Gun Control Act.
Biden spoke how it will “require that the seller and manufacturers make the key parts with serial numbers and run background checks on the buyers when they walk in to buy that package.”
Another legislation order will focus on tightening regulations on pistol-stabilizing braces like the one used in Boulder, Colorado, in a shooting last month that left 10 dead.
The President’s legislation came shortly after the mass shooting in Boulder, Colorado on March 22 that left 10 people dead and the Atlanta, Georgia mass shooting on March 16 that took the lives of eight individuals, including six Asian American women.
In Biden’s campaign for President, he spoke upon making it easier for states to adopt “Red Flag Laws” where it is now mentioned as one of the six executive orders.
“Today, I asked the Justice Department to publish a model Red Flag legislation, so States can start crafting their own laws right now.” said Biden
But his orders stop well short of some of his biggest campaign-trail proposals, including his promise to ban the importation of assault weapons and his embrace of a voluntary gun buyback program.
Many of the necessary actions for gun control must come from lawmakers on Capitol Hill in order to create any lasting change.
"Some of the other big-ticket items are legislative," said Josh Horwitz, executive director of the Coalition to Stop Gun Violence. "And that's going to be very difficult."
In order for Congress to pass any legislation on gun control it would require 60 votes to pass which will be difficult with an evenly-divided Senate.
Another key executive order for Biden was to invest in evidence-based community violence interventions.
“The violence is hitting Black and Brown communities the hardest. But there are proven strategies that reduce gun violence in urban communities, and there are programs that have demonstrated they can reduce homicides by up to 60% in urban communities” said Biden.
Dean Rieck, executive director of Buckeye Firearms Associations, an organization that defends and advances the right of Ohio citizens to own and use firearms for all legal activities, comments on the possibility of a legislation on assault weapons.
“These kind of high-profile cases are terrible but, you know, mass killings with rifles are actually one of the smallest category of murder. The vast majority of murders in the United States happens with handguns.” He said he believes an imposed federal assault weapon ban would be ineffective.
“These guns are just ordinary rifles basically. They’re no more powerful than a hunting rifle, often less powerful than hunting rifles,” Rieck said.
But Abbey Winter, Colorado chapter leader for the national group Moms Demand Action, said that while Colorado has passed some gun laws in the recent years, including background checks and a red-flag law, it has not been enough action on gun safety.
"We're only as safe as our closest state so we need federal action, because we see it as a nationwide public health issue" said Winter.
She added that while mass shootings tend to capture headlines, it's critical to also focus on instances of gun violence that impact communities across the country every day.
"I also want to pay attention to the 100 people who die every day from gun violence, most of the time, not making the headlines," Winter remarked. "Ten of those on average a day are children in this country."
In the year 2021 alone the U.S has had a total number of 13,386 deaths due to gun violence and averaged more than one mass shooting a day this year.
To date, Congress has yet to pass gun legislation on gun control.
Modeling the Interpolation of Slab Depth Versus Seismicity
Abstract
Subduction zones are home to the most seismically active faults on the planet. The shallow megathrust interface of subduction zones host the largest earthquakes and are the only faults capable of M9+ ruptures. Despite this, our knowledge of subduction zone geometry, which may determine the spatial extent and the size of subduction zone earthquakes, is not fully known. Here we use Slab 2 data from the U.S. Geological Survey to find correlation and characteristics of subducting slab depth versus seismicity activity utilizing Terminal and Python to interpolate the data into models. In being able to model slab depth and seismicity activity, these observations may give insight into the hypothesis that dehydration-derived H2O causes intermediate-depth intraslab earthquakes and other dual mechanisms based on their locations and depths. In doing so, this may give insight on the magnitudes of future earthquakes.
Introduction
Subduction zones account for about 90% of the energy released by historical earthquakes globally. These zones will also account for some of the largest earthquakes and are often events that are both damaging and deadly. Being able to have knowledge of the geometry of subducting slabs is significant to understanding the earthquake and tsunami hazards associated with subduction zones. Though several other global subduction zone geometry databases exist, most are limited in either spatial extent or resolution (U.S.G.S), particularly at shallow depths (<50 km), where the largest, most hazardous subduction zone earthquakes (“megathrust” events) occur and where most tsunamigenic earthquakes are located (U.S.G.S). As tsunamis are very sensitive to the geometry of the fault on which slip occurred, detailed knowledge of the shape of the megathrust is critical for hazard assessment (U.S.G.S). In this study, Slab2, a new model describing the 3D geometries of all seismically active subduction zones worldwide, will be utilized to characterize several locations worldwide (Hayes, G., 2018). These model slabs will be from the near-surface to their deepest expressions in the upper mantle. In all, Slab2 models describe the detailed geometry of more than 24 million square kilometers of subducted slabs overall. In particular this study will focus on intermediate (70-300 km) and deep (300-700 km) earthquakes that occur at pressure (P) and temperature (T) conditions. These are most favorable for brittle failure, making their existence a long-standing problem in solid-Earth geophysics (Hayes, G., 2018). The vast majority of these events occur within the downgoing lithosphere in subduction zones. While hypocentral depth distributions within individual slabs vary, there is a global bimodal depth distribution characterized by a decreasing number of events between 70 and 300 km depths and a distinct increase of seismicity in the lower transition zone between 500 and 700 km depths. In this study, the focus will be on both the increase and decrease in seismicity that occurs between 70 to 700 km depths, specifically, plotting their depths against the earthquake depths of the seismicity that have occurred at the slabs, allowing the characterization of the subduction zones.
Observations/Methods:
The models from Slab2 provide comprehensive geometrical analysis of all known slabs gathered by the U.S. Geological Survey data release. The data was then put into code that was created by this study which is available if requested. The data was set to a 10 year time scale and minimum magnitude of 4.0. The compiled data used from the Slab2 dataset was for 14 regions: Caribbean, Central America, Muertos Trough, Himalayas, Hindu Kush, Philippines, Ryukyu, Alaska, South America. Using Terminal and Python, interpolation was done on the slab depth data onto the seismicity data (Fig. 1.0 and Fig. 2.0). The slab depth data was then indexed to remove any seismicity that was not located on the given slab. Lastly, the seismicity was graphed across the slab depth for each region (Fig.3.0).
Analysis
Compiling our results, we found three distinct groups based on earthquake depth against slab depth: no correlation, low correlation, and high correlation. In the models that displayed no correlation, the distribution of earthquake events were random and appeared unrelated to the area of subduction or few are found at all. In the area of low correlation, there were many earthquake events that are disjointed from the subduction zone but some that are seemingly related. The models that had high correlation, the majority of the earthquake events appeared in the subduction zone where the slab was higher in depth.
Discussion and Conclusion
In seeing the three groups of correlation, this may bring to light more on their characteristics and how different subducting slabs vary from one another and their locations, such as why some may see higher correlation and depth versus others that do not. At some locations, if hydrous minerals are present along normal faults in the trench–outer rise region prior to plate subduction, those hydrous minerals may decompose and expel H2O along the faults as the plate subducts to depth (H. Akira, N. Junichi., 2017). It has been proposed that intraslab earthquakes occur along these preexisting planes of weakness that originated as normal faults prior to subduction (Kirby, 1995). It has also been shown in another study that for outer rise events, features of the geometry of the fault system prior to subduction persist down to c. 450 km depth in the subducted slab (H. Akira, N. Junichi., 2017). This suggests that intraslab events down to this depth are caused by the re- activation of preexisting faults containing hydrous minerals that formed prior to subduction (H. Akira, N. Junichi., 2017). This can also be true for intermediate-depth intraslab events in the Middle America and Chile subduction zones and their models. It is also hypothesized that many of these events occur at the phase boundaries of dehydration reactions across which H2O content changes (H. Akira, N. Junichi., 2017). This study can also hypothesize the existence range of hydrous minerals and the locations of the facies boundaries of dehydration reactions within the slabs beneath the subduction zones of Cascadia, Costa Rica and NE and SW Japan.
In a nature article titled Deep earthquakes in subducting slabs hosted in highly anisotropic rock fabric, it quotes “Yet about 30% of the global earthquakes from the International Seismological Centre (ISC) catalog are deep earthquakes associated with subducting slabs”, which may give reason as to why there were some locations that had no correlation (Li, J., Zheng, Y., Thomsen, L. et al., 2018). Another reason why there may not be or little correlation between the earthquake depth and slab depth is that the fault may be in a “locked” state. For example, in the Cascadia Subduction Zone, it has been the site of “megathrust” earthquakes, but is quiet at present. Stress is likely building up as the Fuca plate continues to subduct beneath North America.
To conclude, it is probable that intermediate-depth intraslab earthquakes occur within the existence range of hydrous minerals in the slab crust and slab mantle. Through distincting differences between the slab depth and seismicity around the world, this will give insight on the state of subducting slabs and how it will affect the surrounding environment. This study could be further investigated through improving the accuracy of the models, adding a temperature model, increasing the spatial resolution of seismic tomography imaging of the internal structures of subducting slabs, and deepening our understanding of the detailed processes that lead to earthquake rupture from a state of local excess pore fluid pressure based on rock deformation experiments or numerical simulations.
Figures
Figure 1.0 (Interpolation figures)
Figure 2.0 (Interpolation)
Figure 3.0 (Slab depth vs. Seismicity)
References
Hayes, G., 2018, Slab2 - A Comprehensive Subduction Zone Geometry Model: U.S. Geological
Survey data release, https://doi.org/10.5066/F7PV6JNV.
H. Akira, N. Junichi., 2017. Seismic imaging of slab metamorphism and
genesis of intermediate-depth intraslab earthquakes. Progress in Earth and Planetary
Science. 4. 12. 10.1186/s40645-017-0126-9.
Li, J., Zheng, Y., Thomsen, L. et al., 2018. Deep earthquakes in subducting slabs hosted in highly
anisotropic rock fabric. Nature Geosci 11, 696–700.
https://doi.org/10.1038/s41561-018-0188-3
Kirby, Stephen.1995. Interslab earthquakes and phase changes in subducting lithosphere.
Reviews of Geophysics. 33. 287. 10.1029/95RG00353.