Table of Contents
No, the words “abstract” and “summary” are not interchangeable. An abstract is a brief overview of the main points of a larger work, such as a paper, book, or report. A summary is a condensed version of the same work, containing only the main ideas and leaving out any details or supporting evidence.
An opening statement
Because of the many sources surrounding Puerto Rico, Puerto Rico is vulnerable to earthquakes. Because of this, the likelihood that a tsunami could strike the island goes up as in 1918. The Puerto Rico Trench is located to the north of island and contains two escarpments that have the potential to create tsunamis that could directly impact the northern coast of the island. We will be studying the potential effects and expansion of a tsunami caused by submarine landslides. The escarpments are located along the north coast of the island. The effectiveness of flood maps for this area can be determined by comparing the flooding caused by tsunamis to land. Submarine landslides are generally closer to the coast and can result in potentially devastating tsunamis. They are also more concentrated and have a short arrival time.
IntroductionAfter the 2004 Sumatra earthquake caused a tsunami that devastated seven countries on the Indian Ocean’s coasts, many scientists wondered if similar events could occur due to the limits in the plates. One area of concern is the Puerto Rico Trench. It is located under the Caribbean Plate (Ten Brink. et. al. 2004,). This plate extends about 3200km from North Central America to northern end of sub-area of Lesser Antilles. Grindlay and colleagues, 2005. This is why there is an anomaly at gravity in the Earth’s negative free air with -380 mg Gal. It is located 50 kilometers south of Trench where the water level is 7950m. The archipelago of the Canary Islands, located off the northwest coast of Africa.
Evidence of erosion, tectonic collapse and large-scale subduction are found on the south east platform of the Bahamas and Puerto Rico. Grindlay (2006) believes that the existence of large-scale underwater landslide structures, which could have created massive prehistoric tsunamis along the northern border of Puerto Rico, is alarming. Scientists are concerned about the recent increase in northern Caribbean population, which could lead to future tsunamis that are more devastating or deadly than those of the past.
Two large, amphitheater shaped landslides of amphitheater shape have been discovered in Puerto Rico. They are Arecibo & Loiza. They are situated on the southern slopes the Puerto Rico Trench. These escarpments can reach up to 55 km across, have a crown that extends to approximately 3000m in water depth, and they extend to approximately 6000m in water depth. They were excavated at 3km under water at the edge to a Neogonium-carbonate platform. These escarpments’ ages are unknown (Ten Brink and al., 2004).
These landslides or arches were originally detected by seismic reflection and long-range seismic lateral seismic surveys. (Grindlay et al., 2005; Schwab et al., 1991). This was followed by lateral sweeping bathymetry imagery and a better resolution sonar imaging. The scientists believe that although the amphitheaters did not form during one catastrophic event, the estimated volume that was lost in the landslide area is close to the amount of material that fell in the other. Bathymetry and longitudinal scanning images show that semicircular-shaped escarpments didn’t form from one catastrophic failure as previously suggested. They were created by a continuous retrograde drop of smaller segments.
The possibility that the platform could fail due to an earthquake-related shock and the groundwater flow from Puerto Rico to the undersea springs close to cracking areas on the shelf is possible. These flows could slow down the erosion of carbonate platforms and could contribute to small landslides capable of causing tsunamis.
Additionally, at the margin of the platform, 45 degrees of seabed slope is seen and 4000 meters of water depth are added. This could increase the possibility of a tsunami on Puerto Rico’s north coast. According to Mercado (2002) a submarine slope disaster can take many forms. They include slides, drops, slumps, slips, debris flows or grain flows. In the case of the scarp at the Puerto Rico Trench, the scarp is an amphitheater-shaped result of a landslide exhibiting characteristics of a landslide. As they are often found near coastlines, tsunami warning systems have difficulty predicting them.
The Puerto Rico Seismic Network created evacuation and tsunami inundation maps using seismic events. You can find these maps online at the Puerto Rico Seismic Network website. These maps are based on the possibility of events arising from hundreds of faults located around Puerto Rico. These maps don’t take into account any other possible tsunami sources, like submarine landslides or volcanic eruptions.
The study’s objective was to measure the impact of a tsunami on the three municipalities of Toa Baja and Catano. This study compares floods from these sources. Next, the evacuation maps and tsunami flood maps provided by Puerto Rico Seismic Network are compared to figure out how many assembly points fall within the danger zone.
Mercado (2002) states that modeling landslide tsunamis can be more challenging than modeling earthquake tsunamis. This is because the timescale of bottom displacement is longer than that of an earthquake. The factors that determine the frequency of landslide waves are the volume of material, depth of immersion, speed and velocity of the slide. The sea surface responds more quickly to slides that are faster than tsunami waves.
Bathymetry grids were utilized for modeling landslides. More attention was paid to the 1/3 arcsecond grids obtained by the National Geophysical Data Center(NGDC) (www.ngdc.noaa.gov). The bathymetric grids of Arecibo and Loiza landslide escarpments were used at 5 arcsecond resolution. These scenarios were used for propagation of the wave ampltudes. Lopez-Venegas (2008) described the construction, ordering and nesting of squares with SURFER v.10. The simulation of the tsunami wave’s propagation and flooding was performed using the numerical model algorithm Ocean WAVE nonhydrostatic evolution.
This study required a series to create nested Grids. These grids increase in resolution as the time passes. They are lower with 3 minute grids and higher with 1-3 arc second grids.
Once the floods had been accurately generated, Maximun Inundation Grid values from each run were extracted to create floodmaps using ArcMap. The results were then analyzed using Geographic Information Systems to make comparisons between the flood generated in Loiza by the Amphitheater of Arecibo in Toa Baja and Catano. We compared these floods with flood maps from Catano and Toa baja, which were provided by the Puerto Rico Seismic Network. This allowed us to determine the points within the flood area if there was an underwater tsunami.
Discussion/ Interpretation: A striking similarity can be observed in the arrival patterns of tsunami models created by each amphitheater’s tide gauges along the coast of Catano and Toa Baja. The arrival curves following the first wave front have a similar pattern. There is a difference between arrival times and heights of 300-400 seconds, 200-400 cm, and the eighth tide gauges has a difference reading approximately 1,460cm.
Comparing models of flood extensions that could be generated by the natural landslides of Loiza and Arecibo, as well as the flood exhaustion produced by seismic events, it is clear that the flood caused by an escarpment of Arecibo can cause more damages and extend the earth further than the flood generated to the north by the Seismic Network of Puerto Rico. Comparing the tsunami-generated inundation by a hypothetical landslide at Arecibo Amphitheater with that generated by the Loiza Amphitheater, one can see that it is smaller than that generated by Arecibo Amphitheater.
The escarpment at Arecibo flooded an area of approximately 30.2km2, 11.7 km2 in Catano municipality, 13.4 km2 in Toa Baja municipality, 4.9km2 in Bayamon municipality, and 0.16km2 Guaynabo municipality. Around 40,613 people were affected by this. The escarpment at Loiza caused the flood to extend over a distance of 21.6km, flooding 9.8km2 of Catano’s municipality, 10.9km2 of Toa Baja’s municipality, 0.81km2 the municipality Bayamon, and 0.13km2 in Guaynabo. A total of 29,047 people were affected by this incident. Finally, the Seismic Network of Puerto Rico produced an additional 18.6 km of floodwaters, which flooded an area of 7.1km2 of Catano and 11 km2 of Toa Baja. The municipality of Bayamon was 0.53km away. Affected municipalities affected approximately 25,013 people.
We compared the flood model created by Arecibo’s Amphitheater to the Red Sismica and found that there were three assembly points. There would also be eleven schools, five hospital and six interest rates for Palo Seco Power Plant and Industrial Zone. Comparing the flood model created by the amphitheater at Loiza to that of Red Seismic revealed that two assembly points, ten hospitals, four schools, and three points (Palo Seco power plant, Toa Baja, Industrial Zone, Treatment Plant of AAA of Catano) were located within the flood zone.
This study investigated the vulnerability and vulnerability of various public and private infrastructures as well the vulnerability of assembly areas determined using the SeismicNetwork of Puerto Rico. This was because tsunamis from other sources were not considered when determining the assembly zones in Puerto Rico. This makes it important to consider multiple scenarios with tsunamis generated by different sources.
Conclusion/SummaryThe Puerto Rico Trench located north of the coast of the island of Puerto Rico has a tsunami and seismic potential. According to bathymetric studies, large submarine landslides are a potential source of tsunamis that could immediately hit the island’s north coast. These models were created from hypothetical events generated from the Loiza and Arecibo amphitheaters. They were then compared to the tsunami flood model that was caused by earthquakes.
The flood of tsunami that was caused by a landslide at the amphitheater of Arecibo lasted approximately 11.6km2 longer than the Seismic Network of Puerto Rico’s model of tsunami caused tsunami. Additionally, the 3km2 length of Loiza’s amphitheater exceeded the Seismic Network’s model. This allowed us to show that the flood area would be created by a tsunami generated from the above mentioned amphitheaters, which have three to five assembly points.
It was demonstrated that evacuation maps should be created for tsunamis from all sources. This is because the tsunamis can cause damage to areas greater than what is shown in evacuation and flood maps.