Earlier today, 07/17/2017, a fore shock (M6.2) disrupted the residents of nearby Nikol’skoye, Russia. The earthquake was shallow and the epicenter was offshore. A tsunami warning was issued, but all residents and dwellings remained safe when the tsunami failed to occur. The strong fore shock preceded the powerful M7.8 (Mww) main shock at 23:34hrs UTC. The focal depth was shallow again, at 11kms, and a tsunami warning was NOT issued. Early reports of damages and losses are not available, but the USGS Shake Map estimates strong shaking occurred in Nikol’skoye.
Similar to previous posts, we wanted to capture images of the three long period seismic drums and their recording of the M6.2 (Mww) Russian earthquake on 17072017 at 11:06hrs UTC and 8kms deep. The Jesuits first began operating Weston Observatory, and its seismic instruments, early last century. The uniqueness of these recordings is you may actually watch them record ground movement LIVE and directly connect the earthquake shaking to the output of the instrument. Enjoy!
RUSSIA: At 1106hrs UTC, a strong magnitude 6.2 (Mww) hit a small island in Russia. Although a tsunami warning was issued, it is not known at this time if a tsunami was generated or caused any damage. The epicenter was offshore and about 8kms deep. Damage and Losses Report (the USGS 1-Pager) estimates that: (1) damages and fatalities are expected to be very low, and (2) about 1,000 residents felt weak shaking, see the estimated charts below:
The seismograph shows the different wave forms beginning at the black arrow.
Over 24 hours, two moderately-sized earthquakes have shaken Tonga with force. Earlier today, 7/16/2017 at 17:06hrs UTC (12:06 pm CST) the island shook with a magnitude 5.8 (mb) quake and again another event with magnitude 5.5 (mb) at 01:20hrs UTC (08:20hrs CST). Both focal depths were approximately 10kms deep. The seismograms for both events are shown, in comparison, below:
OKLAHOMA: Small earthquake (magnitude mb 4.1) and yet moderate shaking was felt in Stroud, OK this morning. The focal depth was shallow at 9kms deep and occurred at 13:47hrs UTC (5:47 am CST). Here are the details, captured below:
A new Shake Board design completed AND IT WORKS!!! I combined the Shake Table, Natural Wave Reonance Frequency, foundation geology agfect on horizontal PGA, and a vertical shake component to the original design. Now we may utilize 1 tool while teaching 5 different concepts & associated activities. SO EXCITED!!
We have posted the sounds of the earth quaking as seismic waves pass by our Station, but this particular recording is my new favorite. Listen for the distinct “swishing”‘ sounds of the S wave and then the quieter surface waves from the magnitude mb 6.3 earthquake in New Zealand on 07/11/2017 …. beautiful! That is the sound of rocks moving beneath my feet without even feeling the movement – amazing! Thank you EarthSound!
1 second = 15 minutes
Last night, Spring, Texas experienced a healthy and strong series of thunderstorms. Many lightening strikes were powerful and shook the house, here is what they looked like recorded on the seismometer:
they were the “perfect storms” as all were safe and the storms left a comforting peace throughout the city.
This morning at 12:09hrs UTC (7:09 am CST), Ecuador shook from a moderate magnitude mb 5.3 earthquake. The focal depth was approximately 33kms deep. Although the event was barely detected at Station E1TX, we were able to interpret our own mb magnitude perfectly matched compared to the USGS reported mb magnitude:
Station E1TX detected and recorded the M6.3 earthquake in New Zealand. Below, the red arrow points the first arrival, the PP wave phase. The surface waves are also clearly shown in 08:00 hour (UTC).