Earthquakes, -quaves and -dins

Fri, 13 May 2022 12:30:00 GMT

Talking about earthquakes

According to the Oxford English Dictionary , the earliest recorded use of earthquake in English is from the middle of the 14th century. Alternatives at the time included earthquave, earthgrine and terremote , but how did English-speakers talk about seismic events before that?

The answer is found in an Anglo-Saxon Chronicle annal from Worcester in 1060, which says "In this year [there] was [a] great earth-din".

Earthquakes are certainly noisy, but a lot of the sound is below the range of human hearing. The US Geological Survey have adjusted the frequency of these sounds so we can hear them , but the Anglo-Saxons didn't have this technology.

Here's a recording of an earthquake in Alaska from 2018 , where it's obvious that a lot of the noise is from the movement of the building and its contents.

Taking out the environmental noise, this recording from UC Berkeley may be the best representation of how an Anglo-Saxon might have heard an earth-din.

How to make headlines with citizen seismology

183:786514075 (Paul Denton) — Thu, 28 Apr 2022 10:12:14 GMT

Big headlines for small earthquake

On 8th August 2019 a small earthquake happened in Cornwall, UK. Despite being less than magnitude 3 it caused great excitement locally, and even nationally.

At the time this earthquake happened the deep geothermal energy company United Downs had just set up a network of low cost raspberryshake seismometers in local schools as part of their community outreach programme.

These simple, low cost seismometers easily detected the signal from this earthquake right across the county. Data from these sensors can be downloaded from an online archive using simple Python programs and using the ObsPy Python library

from obspy.clients.fdsn import Client

from obspy import UTCDateTime

import matplotlib.pyplot as plt

# station names

seislist=['RB30C','RB5E8','RD93E','R82BD','R7FA5']

# set the data window

starttime=UTCDateTime("2019-08-08 16:52:05.10")

# read in list of Raspberry Shakes by looping through the list from the second seismometer

client=Client(base_url='https://fdsnws.raspberryshakedata.com/')

waveform=client.get_waveforms('AM',seislist[0],'00','EHZ',starttime,starttime+15)

for x in range (1,len(seislist)):

waveform+=client.get_waveforms('AM',seislist[x],'00','EHZ',starttime,starttime+15)

waveform.detrend(type='demean')

waveform.plot(size=(1024,800),type='normal', method='full',equal_scale=False, starttime=starttime)

See www.dentonseismo.co.uk for more details of educational and citizen seismology and resources

Seismic Musings

Earthquakes, -quaves and -dins

Talking about earthquakes

How to make headlines with citizen seismology

Big headlines for small earthquake