Volcano viewing: aerial photos and volcanic ash: looking back to move forward

A new project at the USGS Hawaiian Volcano Observatory is once again taking advantage of old aerial imagery and field notes that have been used to create geological and hazard maps. Hundreds of ancient field map images and notes are buried at the locations and thickness of many ash deposits on the sides of Mauna Loa whose quantities have not been fully quantified.

Ash deposits are the product of explosive volcanic eruptions that periodically dominated earlier volcanic activity. The largest volcanic eruptions deposited layers of thick ash that covered large areas of the Kilauea and Mauna Loa volcanoes. Knowing the locations and thickness of the relevant ash deposits allows us to better characterize the explosive nature of these eruptions.

Aerial photos of the Earth’s surface can be captured from any type of aircraft, including satellites, planes, helicopters, or unmanned aircraft systems. In conventional aerial photography, a large camera is mounted underneath a fixed-wing aircraft that flies in rows of straight lines, and takes a series of overlapping images of the area underneath.

Aerial view binoculars can be slanted or vertical, depending on their intended use. Several air images are used to create orthopedic images, which are vertical aerial images that have been corrected to remove distortion from camera tilt, lens aberrations, and topographic topography. Both calendar and topographic maps can be made from aerial photos and allow real distances and angles to be measured.

The USGS mapping group began acquiring aerial mapping images in the 1930s in cooperation with the Army and the United States Department of Agriculture. At least one aerial photographic survey was conducted every decade between the 1950s and 1970s for every Hawaiian island. Above the island of Hawaii, for example, photographic surveys were conducted in 1954 (USGS HAI), 1961 (USGS VXJ), 1964-1965 (USDA EKL), 1976-1978 (USGS VEEC)

Digital copies of black and white aerial photos of the Hawaiian Islands can be accessed through the University of Hawaii at Manoa: Maps, Aerial Photos, and the GIS website (https://guides.library.manoa.hawaii.edu/magis). The website provides an image viewer with the airlines taken during the surveys and the location of each aerial photo.

HVO geologists used aerial imagery as a primary method for mapping geological features and determining their position in the field before the widespread availability of the Global Positioning System (GPS). They used landmarks (roads, trees, buildings, faults, and streams) to find where they were in the field, then put a pin hole in the aerial photo and marked the back with the location number. They recorded the site number in their field notebook, along with the geological observations made in that area. Interestingly, this is still a useful skill when you can’t get a good GPS location.

Gathering decades-worth of aerial photos and field notes into digital format is a daunting task. To date, more than a thousand ash sites have been collected around the island of Hawaii, primarily on Mauna Loa. Among them, about 230 stratigraphs containing the ash were created, based on information from ancient field observations and limited by the ages of the lava flows that have been dated.

Dating of coal found within ash deposits and adjacent lava flows helps to restrict the number of times explosive eruptions occur. See Volcano Watch’s October 22, 2020 article, “Coal, a Game-Changing Agent for Understanding Operations in Young Volcanic Terrain.”

The ash deposits on the sides of Mauna Loa span from 380 years old to over 31,000 BC. Ash ranges in thickness from about 3 cm (1 in) to over 10 m (33 ft). However, much work remains to be done to determine the frequency of explosive eruptions and the number of individual explosive events these ash layers represent.

New information extracted from these ancient aerial photos and from revisiting these sites will contribute to a better understanding of future explosive eruptions on the island of Hawaii. Ash prospects contain important information about eruptions including how large they can reach, where their sources are, and how often. The goal is to build better assessments of explosive hazards and how they might affect communities currently living on the fringes of Hawaii’s most active volcanoes.

Volcano activity updates

Kilauea volcano erupting. USGS Volcano Alert Level at WATCH (https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels). Kilauea updates are released daily.

Lava activity is limited to Halema’uma’u with lava erupting from a vent on the northwest side of the crater and flowing into a growing lava lake. Laser rangefinder measurements this morning, March 25, indicate that the lava in the western (active) part of the lake is 224 meters (735 feet) deep, with the eastern part of the lava lake solidifying at the surface. The top propensity gauges showed no inflation or deflation bias over the past day. The sulfur dioxide emission rates measured on March 22nd were 950 tons / day. Earthquakes remain stable, with higher tremor. For the most recent information on the eruption, see https://www.usgs.gov/volcanoes/Kilauea/current-eruption.

Mauna Loa does not erupt and is still at Volcano Alert Level. This alert level does not imply that a volcano eruption is imminent or that progression to an eruption from the current level of turbulence is a certainty. Mauna Loa updates are released weekly.

Last week, about 81 small-scale earthquakes were recorded under the upper elevations of Mauna Loa; Most of these occurred at depths of less than 6 kilometers (about 4 miles). GPS measurements show continued slow summit swelling, consistent with the supply of magma to the volcano’s shallow storage system. The slight increase in the inflation rate continues at the peak that began in January. Gas concentrations and fumarol temperatures both at the summit and in the sulfur cone in the southwest rift region remain stable.

Web cameras do not show any changes to the landscape. For more information on the current monitoring of Mauna Loa volcano, see: https://www.usgs.gov/volcanoes/mauna-loa/monitoring.

There have been 4 events with 3 or more hairy reports in the Hawaiian Islands over the past week: M2.9 earthquake 8 km (4 mi) ENE from Pahala at a depth of 31 km (19 mi) on March 24 at 8:27 AM HST, M3.0 9 km (5 mi) SSW earthquake from Leilani Estates at 5 km (3 mi) depth on March 23 at 9:34 pm HST, M2.7 earthquake 3 km (1 mi) south of Pahala at 31 km ( 19 miles) depth on March 18 at 1:06 PM GMT, and an M3.5 earthquake 20 km (12 mi) northwest of Volcano at a depth of 2 km (-1 mi) on March 18 at 8:23 a.m. HST.

HVO continues to closely monitor both the ongoing Kilauea eruption and Mauna Loa for any signs of increased activity.

Please visit the HVO website for previous Volcano Watch articles, Kilauea and Mauna Loa updates, volcano photos, maps, recent earthquake information, and more. Questions emailed to [email protected].

Volcano Watch is a weekly article and activity update written by the scientists and affiliates of the Hawaiian Volcano Observatory of the US Geological Survey.

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