12 Aug 2020
Some may not know this, and is well worth knowing that at Ulladulla High School we have seismometer station. You may ask, what is a seismometer station? A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions, and explosions. The normal hum of human activity was significantly reduced during the COVID-19 lockdown period and is the longest and most prominent global human seismic noise reduction on record. Seismometers which are used globally to measure the Earth’s movement normally need to filter out all the sounds of human activity and listen carefully for the sounds due to volcanic eruptions and earthquakes. Without the noise of human activity, these devices were more clearly able to detect and measure these events. A recent research publication examined the global network of seismometer stations, including the station at Ulladulla High School which is part of the Australian Seismometers in Schools project (http://ausis.edu.au/), to measure the difference in pre-lockdown and lockdown noise. The researchers examined the seismometer data from 268 seismometer stations globally and found that in 185 of these stations (including Ulladulla High School) there was a significant reduction in noise levels. This also provided an opportunity to detect more subtle signals from the Earth that would otherwise have been undetectable in normal times due to human noise.
The local noise levels before lockdown and after lockdown are shown in the below graphs, the scale around the circle represents the time of day on a 24-hour clock face and the scale moving from the centre of the circle outwards represents an increasing noise level from human activity, each coloured line representing the day of the week. What this data proves is that our community, during the lockdown period, took serious notice of the warnings and made a significant reduction in our normal activity to help reduce the possible spread of COVID-19 in our community.
The research article is published online and is freely available at http://tiny.cc/68uksz.
