Israel military detects 6 blasts, each 11 seconds apart, before Beirut explosion | Hacker News Reader

Israel military detects 6 blasts, each 11 seconds apart, before Beirut explosion

reuters.com

22 pointsKhelavaster15 comments

Geophysicist here.

These 11 second periodic blasts are due to airguns from a Turkish seismic survey vessel that happened to be working in the region. N.B. they continued after the Beirut explosion.

Here's a (long; thanks Zuck) link to a FB post from IRIS (the Incorporated Research Institutions for Seismology):

https://www.facebook.com/IRISEarthquake/photos/a.36102058997...

> “I do not believe that they are associated with the large explosion in Beirut,” Jerry Carter, director of IRIS data services, told Reuters.

> “They could be from a seismic survey,” he added, referring to geologists carrying out airgun bursts for underwater mapping.

It’s not the Israeli military that claims that, it’s an Israeli seismologist that works for an oil company.

> Hayoun assessed that the Beirut incident involved underground explosions. The 43-metre (140-foot) deep crater at the port could not have been left by the explosion of the amount of ammonium nitrate reported by Lebanese authorities, he said: “It would have been shallower, maximum 25 or 30 metres.”

To make a claim about “maximum crater depth” seems like you’d need a lot of data about the ground composition below the storage area, and if the anfo was in a concrete silo that could amplify the blast by letting pressure build before failing etc

They should also investigate how the fire started in the warehouse. Some warehouse fire setting are just arson or have business motivations like insurance fraud. In many cases they have no idea what else is stored in the warehouse and things can go really wrong.

Interesting that Isreal is (maybe) capable of detecting far away fireworks bursts. I wonder how they filter out meaningless noise.

My naïve guess is that it's used to assist in triangulating where incoming rockets / mortars are fired from.

Edit: I read the article and it has nothing to do with the Iron Dome (unless it's military equipment posing as science equipment).

Sure. I'm curious if they have some ML or other tech to weed out false positives.

Also tunnels - https://uk.reuters.com/article/uk-israel-lebanon/israel-to-b...

I could speculate that an array of seismic or comparable detectors would be able to pick up direction and with filtering and processing, identify the type of source.

Somewhat relevant link: https://www.newscientist.com/article/dn28700-earthquake-dete...

>I wonder how they filter out meaningless noise

If the meaningless noise is local, I would try employing multiple detectors separated widely.

I mean meaningless noise like mining, road building, seismic tests, fireworks displays, etc, versus actionable stuff.

I would expect that the IDF has sonobuoys and hydrophone nets everywhere they can stick them in the area. Their neighbors have various large and small warships and have a history of using them via surprise tactics.

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