Hawaii earthquake likely related to tectonic plate curvature

On October 10, 2021, a 6.2-magnitude earthquake near the southern coast of the Big Island struck residents and visitors throughout the state of Hawaii.

Written by Lillian M. Burchard, Lauren A. Ward, Ph.D. Helen A.; NOAA/NWS Pacific Tsunami Warning Center

Citation: Burkhard, LML, Ward, LA, Janiszewski, HA, Smith-Konter, BR, Weiss, JR, 2021, Hawaiʻi offshore zake related to plate tectonic bending, Temblor, http://doi.org/10.32858/temblor.215

View of the Kīlauea lava field toward the ocean in southeast Hawaii’s Big Island. Credit: L. Burkhard

When a 6.2-magnitude earthquake hit the southern tip of Hawaii’s Big Island last week, a tremor was felt across the Hawaiian chain, including Honolulu on the island of Oahu, about 160 miles (260 kilometers) away.

The earthquake occurred at a depth of 22 miles (35 kilometers). According to the US Geological Survey (USGS), it resulted from simultaneous horizontal and vertical movement along the subsurface inverse fault. This type of “slant reverse fault” occurs when rocks are sheared and compressed.

Large island earthquakes are often caused by magma flowing under Kīlauea or Mauna Loa, the two active volcanoes on the island. These shallow earthquakes are generally small, and most are imperceptible by all sensitive seismic devices. Swarms of these earthquakes sometimes precede an eruption.

However, two other types of earthquakes occur in Hawaii. They result from either a rift within the sides of active volcanoes or a bending (“flexion”) of the Earth’s crust and upper mantle due to the weight of the islands (Watts and Ten Brink, 1989; Wessel, 1993; Klein, 2016). Earthquakes related to volcanic bending and lateralization can be very large.

Big Hawaii earthquakes

The largest earthquake in Hawaii in the past 150 years was the 1975 Kalapana earthquake of magnitude 7.7, which was a side event that struck along the southeastern shore of the Big Island. The event moved the south side of the Kīlauea volcano southward (eg, Swanson et al., 1976; Lipman et al., 1985; Nettles et al., 2004; Owen and Burgmann, 2006; Chen et al., 2019) and triggered a local tsunami. , which caused the death of two people. It caused an estimated $4.1 million in property damage.

In 2018, a similar type of wing event occurred nearby at a depth of 3.6 miles (5.8 kilometers). This earthquake was associated with the formation of new lava vents in the area during the 2018 eruption (Neill et al., 2019) and likely resulted from slippage on a large fault separating the volcano from the underlying oceanic crust (Lai et al., 2018; Chen et al., 2019).

Earthquakes of magnitude 5.5 and greater from the 1976–2021 Global Tensor Dataset (GCMT) (Dziewonski et al., 1981; Ekström et al., 2012) and the moment tensor for the 04/26/1973 event are from Unger and Ward (1979). Earthquakes greater than 10 miles (15 kilometers) deep are depicted as red/white beach balls and those surface earthquakes as black/white beach balls. The faint white dots are earthquakes from 1933-2018 (Matoza et al., 2021).

Plate flexion earthquakes are not uncommon

Flexion-related earthquakes occur at depths of 10 to 35 miles (15 to 60 kilometers), which is not unusual in Hawaii. Last week’s event was likely caused by plate flexion. Similar to the way a diving board flexes when a person stands at the end, the shell flexes under the weight of the islands. Among the Hawaiian Islands, the Big Island is currently pushing the plate down with the greatest force and is landing at about 0.1 inch (2.5 mm) per year. In contrast, the Oʻahu is slowly lifted upward as it sits atop a bulge that forms in response to flexion. Flexibility-related earthquakes occur when stresses associated with bending are suddenly released when a fault slips.

Schematic view of the southeastern part of the Hawaiian Islands depicting tectonic plate bending and the different types of earthquakes that occur on the Big Island. Credit: Modified by Grigg (1982), Grossman et al. (1998), Morgan et al. (2003) and Klein (2016)

What makes last week’s earthquake particularly interesting is its large magnitude. Most of these deep earthquakes are less than about 5.0 degrees (Klein, 2016). Only four flexural-related earthquakes of magnitude 6.0 and greater have been recorded since the devastating 6.2-magnitude Honomu earthquake in 1973, which struck northern Hilo and caused more than $5.6 million in damage. The largest earthquake ever recorded was the 2006 Kohulu Bay offshore event of magnitude 6.7, which resulted in an aftershock of magnitude 6.0 (McGovern, 2007).

Fortunately, despite the widespread shaking that occurred, last week’s earthquake did not generate a tsunami. So far, the quake has been followed by at least 30 aftershocks, the largest of which was a magnitude 4.2 five minutes after the main quake. Neither the main tremor nor any aftershocks seem to have had any effect on the ongoing eruption at Kīlauea.

It is also possible that this event was unrelated to an ongoing deep seismic swarm in the Pahala region on the south-central coast of the Big Island, located about 30 miles (50 km) to the northeast. Pāhala activity is likely related to an increase in mantle-derived magma driving volcanic and seismic disturbances at Kīlauea, Mauna Loa, and Kamaʻehuakanaloa (formerly Lōʻihi) volcano (Burges & Roman, 2021).

Although significant damage to the islands is unlikely based on the low level of vibration that occurred, the Hawaii County Civil Defense recommends residents search their homes. This earthquake serves as a reminder that visitors and residents throughout Hawaii should be prepared for a variety of geographical hazards including earthquakes, tsunamis, and volcanic eruptions.

references

Burgess, M.K. and Roman, D.C. (2021). Ongoing (2015-) magma eruption in the upper mantle below the island of Hawaii. Geophysical Research Letters, 48 ​​(7), doi: 10.1029/2020GL091096.

Chen, K., Smith, J. D., Avouac, J., Liu, Z., Song, Y. T., & Gualandi, A. (2019). The Hawaii Mw 7.2 earthquake started on May 4, 2018 by storming the dam. Geophysical Research Letters, 46(5), 2503-2510, doi: 10.1029/2018GL081428.

Dzyonsky, AM, T.- A. Chou and JH Woodhouse, Determining earthquake source parameters from waveform data for global and regional seismic studies, J. Geophys. Res., 86, 2825-2852, 1981. doi: 10.1029/JB086iB04p02825.Ekström, G., M. Nettles, and A.M. Dziewonski, The Global CMT project 2004-2010: Centroid-moment tensors for 13,017 earthquakes, Phys. planet earth. Inter, 200-201, 1-9, 2012, doi: 10.1016/j.pepi.2012.04.002.Grigg, R.W. Darwin Point: Threshold for Atoll Formation. Coral Reefs 1, 29–34 (1982), doi: 10.1007/BF00286537.

Grossman, E., Fletcher III, C. & Richmond, B. Holocene sea level rise in the tropical Pacific: isolated database analysis at the Paleocene level. Coral Reefs 17, 309-327 (1998), doi: 10.1007/s003380050132.

Klein, FW (2016), Flexion of the lithosphere under volcanic convection in Hawaii: Internal stresses and a fractured plate revealed by earthquakes, J. Geoffs. Precision. Solid Earth, 121, 2400-2428, doi: 10.1002/2015JB012746.

Lay, T., Ye, L., Kanamori, H., & Satake, K. (2018). Regression constraint in shallow and shallow diphthongs thrust events using long love wave radiation patterns: applications on the 25 October 2010 Mentawai, Indonesia, and 4 May 2018 Hawaiian island earthquakes. Geophysical Research Letters, 45, 10342-10349. doi: 10.1029/2018GL080042.

Lipman, BW, Lockwood, JB, Okamura, RT, Swanson, DA, & Yamashita, KM (1985). Earth deformation associated with the 1975 magnitude 7.2 earthquake and resulting changes in the activity of the Kilauea volcano, Hawaii (Professional Paper No. 1276). Retrieved from https://pubs.usgs.gov/pp/1276/report.pdf

Matusa, R. S., Okubo, P.G., & Shearer, PM (2021). High-resolution mass transmission of the Island of Hawaii earthquakes 1986-2018. Earth and Space Sciences, 8(1). doi: 10.1029/2020EA001253.

McGovern, B.J. (2007), Bending stresses under Hawaii: implications for 15 October 2006, Earthquakes and the rise of magma, Geophysics. Precision. Lett., 34, L23305, doi: 10.1029/2007GL031305.

Morgan, J. K., Moore, G. F., Clague, DA, 2003. Slope failure and volcanic spread along submarine south side of Kilauea volcano, HI. J Geoffs. Precision. 108, 2415.

Neal, CA, Brantley, SR, Antolich, L, Pap, JL, Burgess, M, Callis, K, et al. (2019). 2018 rift eruption and summit collapse of Kīlauea volcano. Science, 363 (6425), 367–374, doi: 10.1126/science.aav7046.

Nettle, M (2004). Long-term source characteristics of the 1975 Kalapana earthquake, Hawaii. Bulletin of the American Seismological Society, 94(2), 422-429, doi: 10.1785/0120030090

Owen, S. & Burgmann, R. (2006). Increase in Volcanic Collapse: Kinetics of the 1975 Kalapana Earthquake in Hawaii. Journal of Volcanology and Geothermal Research. 150. 163–185, doi: 10.1016/j.jvolgeores.2005.07.012.

Swanson, D. A., Duffield, W. A., & Fiske, R. S. (1976). Displacement of the southern flank of Kilauea volcano: as a result of strong intrusion of magma into rift zones (Pro Paper No. 963).

Unger, J.D., and P.L. Ward, Great Deep Hawaiian Earthquake – Honuma, Hawaiian event on April 26, 1973, Bull. syrnol; AM Company, 69, 1771-1781, 1979.

Wessel, P. (1993), A reexamination of flexural deformation under the Hawaiian Islands, J. Geophys. Res, 98 (B7), 12177-12190, doi: 10.1029/93JB00523.

Wessel, P., Luis, J. F., Uieda, L., Scharroo, R., Wobbe, F., Smith, WHF, & Tian, ​​D. (2019). Version 6. General Mapping Tools. Geochemistry, Geophysics, Geological Systems, 20, 5556-5564. doi: 10.1029/2019GC008515.

Watts, AP, and Ten Brink, US (1989), Crustal Structure, Flexion, and Subsidence History of the Hawaiian Islands, J. Geoffs. Resolution, 94 (B8), 10473-10500, doi: 10.1029/JB094iB08p10473.

What Are The Main Benefits Of Comparing Car Insurance Quotes Online

LOS ANGELES, CA / ACCESSWIRE / June 24, 2020, / Compare-autoinsurance.Org has launched a new blog post that presents the main benefits of comparing multiple car insurance quotes. For more info and free online quotes, please visit https://compare-autoinsurance.Org/the-advantages-of-comparing-prices-with-car-insurance-quotes-online/ The modern society has numerous technological advantages. One important advantage is the speed at which information is sent and received. With the help of the internet, the shopping habits of many persons have drastically changed. The car insurance industry hasn't remained untouched by these changes. On the internet, drivers can compare insurance prices and find out which sellers have the best offers. View photos The advantages of comparing online car insurance quotes are the following: Online quotes can be obtained from anywhere and at any time. Unlike physical insurance agencies, websites don't have a specific schedule and they are available at any time. Drivers that have busy working schedules, can compare quotes from anywhere and at any time, even at midnight. Multiple choices. Almost all insurance providers, no matter if they are well-known brands or just local insurers, have an online presence. Online quotes will allow policyholders the chance to discover multiple insurance companies and check their prices. Drivers are no longer required to get quotes from just a few known insurance companies. Also, local and regional insurers can provide lower insurance rates for the same services. Accurate insurance estimates. Online quotes can only be accurate if the customers provide accurate and real info about their car models and driving history. Lying about past driving incidents can make the price estimates to be lower, but when dealing with an insurance company lying to them is useless. Usually, insurance companies will do research about a potential customer before granting him coverage. Online quotes can be sorted easily. Although drivers are recommended to not choose a policy just based on its price, drivers can easily sort quotes by insurance price. Using brokerage websites will allow drivers to get quotes from multiple insurers, thus making the comparison faster and easier. For additional info, money-saving tips, and free car insurance quotes, visit https://compare-autoinsurance.Org/ Compare-autoinsurance.Org is an online provider of life, home, health, and auto insurance quotes. This website is unique because it does not simply stick to one kind of insurance provider, but brings the clients the best deals from many different online insurance carriers. In this way, clients have access to offers from multiple carriers all in one place: this website. On this site, customers have access to quotes for insurance plans from various agencies, such as local or nationwide agencies, brand names insurance companies, etc. "Online quotes can easily help drivers obtain better car insurance deals. All they have to do is to complete an online form with accurate and real info, then compare prices", said Russell Rabichev, Marketing Director of Internet Marketing Company. CONTACT: Company Name: Internet Marketing CompanyPerson for contact Name: Gurgu CPhone Number: (818) 359-3898Email: [email protected]: https://compare-autoinsurance.Org/ SOURCE: Compare-autoinsurance.Org View source version on accesswire.Com:https://www.Accesswire.Com/595055/What-Are-The-Main-Benefits-Of-Comparing-Car-Insurance-Quotes-Online View photos