#Earthquake swarm off of #Oregon

There is an ongoing swarm of earthquakes off of the coast of Oregon, with over a dozen M5+ events over the last day. The shaking hasn’t been felt onshore …

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The theory of Plate Tectonics is the basis for our understanding of Earth’s geology. How that theory was developed, and the verification of it through cold war submarine hunting, is an amazing story of science and technology. The Pacific Northwest is a complex and interesting area, with three tectonic plates mashing together (or in the case of the Pacific and Juan de Fuca plates, spreading apart). The subduction zone where the North American Plate is riding over the top of the Juan deFuca plate is the cause of the volcanoes in Oregon and Washington, including the infamous Mount Saint Helens. Here is a USGS graphic showing the general situation:

USGS Diagram of Cascadia region.

As can be seen the swarm is along a section of the boundary between the Juan de Fuca and Pacific plates where the plates are grinding against each other rather than spreading apart (in geological terms, a transform boundary rather than a divergent boundary). Transform boundaries tend to produce earthquakes, so this swarm isn’t terribly unusual, although the number above Magnitude 5.0 is more than we normally see.

While this swarm isn’t a threat, it is a reminder that the Pacific Northwest is a geologically unstable area, and destructive earthquakes and volcanic eruptions are always lurking just under the surface.

Major M7.5 earthquake in Peru

There was a major earthquake in Peru this morning (Sunday, about 5:52am ET). Fortunately it was in a sparsely populated area, and was at least 100km deep, which seems to have limited the damage. Economic impact estimates are all below $50 Million, the mean of the TAOS/EQ models is $4.4 Million with many of the ensemble estimates below $1 Million USD. Here is the impact map …. given the depth and magnitude, it was actually felt all over Ecuador and Peru.

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Invest area off the US East Coast, Earthquakes in #Japan and #Pakistan

There was an earthquake near Tokyo this morning US East coast time (evening Japan time), reports are coming in but some scattered damage (link goes to Japan Times). Given the quality of construction there, not expecting major damage …

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Yesterday it was Pakistan’s turn, this one did cause at least 20 fatalities (link to Al Jazeera)

In the tropics, there is a weak tropical storm headed to Hainan Island, China, but shouldn’t cause a lot of damage. There is an invest area just off the east coast of the US, part of a very messy pattern across the southeast. Here is this morning’s analysis from TAFB (part of the National Hurricane Center):

The invest is the “L” off the South Carolina coast. NHC has it tagged with a 20% chance of becoming worthy of advisories. It is now being simulated by some of the models as AL92, but more than likely won’t cause anything but rain along the coast as it parallels the shoreline while moving northeast.

Earthquakes in the SC Low Country and Savannah

Just before 10 pm on the evening of August 31, 1886, residents of the Low Country thought the world was ending. The earth shook violently for over a minute, and in many areas the ground seemed to turn into quicksand, collapsing sturdy brick buildings in an instant. The earth continued to rumble, and a second major shock hit around 4am. Those few who slept did so outside. As the sun rose, the devastation became apparent …

Charleston, SC, after 31 August 1885 earthquake

In Savannah, terrified people ran out into the streets, and one woman leapt from her second story bedroom with her baby in her arms (they survived). But others were not so lucky, and while accurate death tolls were not kept, it was likely near or over 100. Although it took days for the full extent of the event to be known, it was felt over 2.5 million square miles, from Cuba to New York, with structural damage as far away as Kentucky. Every major building in Charleston is said to have been damaged or destroyed. With the recent spread of the newfangled technology of photography, we have a record in images of the aftermath (link goes to collection at the University of South Carolina). In Savannah, a twenty foot long fissure opened on Bay Street, and the facades on several buildings on Broughton Street collapsed.

The violence of the 1886 event came as a surprise to residents of the area – major earthquakes are not frequent. Historical studies reveal three major ruptures: the 1886 quake, one in the 1600’s, and one in the late 1300’s or early 1400’s. There is also evidence of additional earthquakes over the last 6000 years in the sediments of the region. Today we know a lot more about the subsurface geology of the Charleston-Savannah area. The University of South Carolina has a network of seismographs monitoring the region in real time …

Seismograph record for September 27th, 2021,

Just inland of the City of Charleston lies what we know today as the Middleton Place – Summerville Seismic Zone (MPSSZ). It is a complex structure consisting of at least two active faults. Unlike faults in the western US, these faults are buried under hundreds of feet of sediments and there is little evidence to be seen at the surface. While most people never feel them (or think it’s just a passing truck or car wreck on Victory Drive), there are on average between 10 and 15 minor earthquakes a year. By careful analysis of these events, the subsurface geology can be mapped, as seen in this diagram …

From Dura-Gomez and Talwani, 2009 (link goes to research paper).

The earthquake on September 27th was a reminder that deep under the earth there are forces that build over time, and must be released. While not located on a plate boundary, the Charleston area is on a dangerous, deep fault system that will from time to time violently rupture. Simulations show that if the 1886 earthquake were to happen today, there would be at least 45,000 people injured and thousands needing hospitalization for major injuries. Over 200,000 would be homeless. Many roads would be impassable, a third of hospitals in the low country and Savannah would be out of commission. The Beaufort and Hilton Head areas would also be severely impacted, with liquefaction (the ground becoming unstable due to high water tables and shaking) causing major damage and loss of life. While the most severe devastation would be in the Charleston area, many of the major buildings in Savannah would be damaged, with hundreds injured and dozens likely to die, and there would be structure damage across the US East Coast.

Unlike a hurricane, unfortunately while we know where earthquakes happen, we don’t know when the next one will occur. We can only estimate the probabilities. Here is the latest analysis from the USGS National Seismic Hazard Model …

Latest USGS probability of damaging earthquake in the US

So what are the odds? It looks like the chances of a major earthquake on these MMPZ system are about one in 400. By comparison, the chances of your home being severely damaged by a tornado is about 1 in 300, by other thunderstorm related winds about 1 in 180. A tsunami? Hard to say, the worst odds I’ve seen based on a solid scientific study are around one in 47,000, but I think they are much lower, probably over one in 250 thousand. The chances of a home in the Low Country and Savannah area being damaged by a hurricane is about one in 30, destroyed about one in 110. So while this is a risk to be aware of, and the consequences of a major earthquake extreme, there are other things to worry about. It is worth looking at the DHS/FEMA web site for earthquake preparedness (link), and remember that most of the things you do to prepare for a hurricane or other event are similar to that for other disasters.

#Shaheen landfall near #Sohar #Oman, Atlantic Update, things that go boom

There is only one tropical cyclone that is a serious threat to land, Cyclone Shaheen at the mouth of the Persian Gulf, although there are three other active storms. And of course there is the eruption of the volcano on La Palma continuing to intensify. Here’s some details …

Cyclone Shaheen (formerly Gulab) is a hurricane headed towards Oman. While unusual, this isn’t rare, but it is all the more disruptive since they don’t happen too often. Given the fragility of energy markets at the moment, and as noted before traders don’t usually need anything more than an excuse for price volatility, it is something to watch. The 5am ET Saturday JTWC forecast has the storm making landfall as a hurricane just south of Sohar, Oman tomorrow evening. A slight shift northward could bring the major oil and gas complexes at Fujairah, UAE within the impact zones …

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With the increased intensity forecast and track shift, the potential impacts of Shaheen have risen quite a bit, to the $1 to $2 Billion range. JTWC forecasts tend to be on the high side, so that may be a bit high and an estimate in the $500m range may be more realistic, but given the impacts of Cyclone Gonu in 2005 the higher numbers are certainly possible.

In the Atlantic, Sam has safely passed Bermuda and is tracking north towards Iceland. The only impacts on the Canadian Maritime Provinces and the benighted points south of the border are waves and rip currents. Likewise, Tropical Storm Victor is fading away further to the south and east, not threat to anyone but fish. You don’t often see the words tropical storm and Russia in the same sentence, but the fading Mindulle has passed offshore of Japan and is expected to complete its extratropical transition over the Kuril Islands and pass near the Kamchatka Peninsula.

Finally, the ongoing eruption of Cumbre Veija on the island of La Palma continues to cause damage, chasing people from their homes. The main lava flow has reached the ocean, generating clouds of steam and – more dangerously – toxic chlorine fumes (from the salt water). Here is some spectacular video of the eruption, with two new vents opening. There is a lot of, um, “stuff” floating around the intertubes about the potential for a catastrophic tsunami from this volcano. Grumpy cat says “how about no.” While a local tsunami for areas near the volcano is definitely possible in the even the eruption becomes explosive, the chances of a major tsunami impacting the US east coast from this is pretty close to nil. And the longer the eruption goes on, and the more seismic activity, the less likely the 150 foot wall of water sweeping across the US east coast becomes (and to be clear, it was always much smaller than, say, a similar event from and asteroid or comet impact – which again is very small). So if you just have to worry, worry about the fools driving crazy on I-16 with all the construction (a local Savannah thing right now).

#Gulab makes landfall in #India, #Mindulle to skim #Japan, #Crete earthquake, and nothing to worry about right now (#Sam and the Atlantic)

There was a significant earthquake in Crete today, that was felt across the region. There have been reports of injuries and and least one death, and several aftershocks.

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Cyclone Gulab made landfall in India. The biggest problem has been heavy rain and flooding, although several fisherman were reported killed in waves and wind offshore.

Typhoon Mindulle has encountered a less favorable environment and dropped from a peak wind of 145 knots to only 90 knots. That’s a reduction in wind pressure by a factor of 2.6 and of damage potential a factor of 4.2. It is expected to regain some strength, but is expected to pass far enough off the coast of Japan to cause only light impacts.

The more observant among you will notice I haven’t mentioned the Atlantic yet. That’s because it’s not really that interesting from a threat standpoint. Yes, Hurricane Sam is an intense storm and interesting meteorologically, but it is presently not forecast to threaten land in the next five days, and signs are it may go far enough east of Bermuda to not be a threat to them either (but they still need to be watching). In the exception to the “no spaghetti tracks” guideline, here’s the current major track models …

There are a couple of waves coming off of Africa that may develop tropical characteristics, but the long range prospects for them are not worth spending any time on at this point (of course, those who make a living from keeping you hyped up will, ad nauseum). NHC has them at 80% chance of them starting tracking, but the long range models are not enthusiastic at this point for their prospects. I just heard some talking head on the radio here in Savannah warn of rip currents, but Charleston Weather Service does not have any cautions posted at the moment (their nifty experimental risk dashboard is “green” … click link here).

Doomwatch, 26 Sept 2021: Supertyphoon #Mindulle and #Japan, #Gulab and #India, Hurricane #Sam and, well, nobody but fish

There are two major (Saffir Simpson Category 3 or higher) storms stalking the earth this morning, but only one is threatening land. There are also earthquakes, volcanoes, and of course the SARS-COV-2. Here’s the overview …

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One thing that stands out on the dashboard are all the earthquakes. None seems to have caused any significant damage, but there have been a lot of them the last three days. As for tropical cyclones, we have two that are threatening land. Cyclone Gulab is making landfall today as a weak storm hitting the east coast of India. It’s hard for a storm to hit India and not impact millions of people, given the population density. Economic impacts should be in the 10’s of millions of US Dollars of equivalent purchasing power parity damage …

In the western Pacific, Supertyphoon Mindulle is starting to recurve north and is forecast to be just offshore Tokyo in about five days. On this track impacts would be light, but a wobble to the left could be Very Bad, so this needs watching …

In the Atlantic, Major Hurricane Sam is a small but very intense hurricane. Fortunately on the current track there is no one in the way for the next five days according to the official forecast …

The track models are tightly grouped over that period. Longer range, it may be an issue for Bermuda, but that’s at least 7-10 days away. Nobody else needs to worry about this one. For perspective here are the long range track models … and for my Canadian friends, way too early to get excited, 10 day forecasts are really iffy especially for tropical systems that far north.

Elsewhere, Teresa is no more, so all of the telenovela references I had planned will have to wait until 2027 in the hopes a storm more deserving of the name shows up. There’s a couple of waves coming off of Africa the chattering class will likely talk about since Sam isn’t a problem. Feel free to ignore them.

I haven’t said much about the pandemic lately because from a scientific and emergency response standpoint there’s not much to say other than global governance is a (colorful language deleted) mess. Like so many issues, this isn’t a technical problem, it’s a political problem. Pick any aspect – masks, vaccinations (who, with what, and when), movement restrictions, natural immunity, and so forth, the technical aspects of public health and medicine are secondary and even tertiary to the politics. In the US, both political parties are criminally negligent in the matter, and internationally the situation isn’t a lot better (and often worse in developing countries). As long as people keep electing (or tolerating, or having forced on them) incompetent leaders you will get incompetent results.

Cape Verde Islands/#LaPalma Volcano hype

Those of you living within 50 miles or so of the US East Coast may have noticed you’re not dead this morning (true, it’s Monday, but that doesn’t count), and might be wondering why since the Cumbre Vieja volcano erupted yesterday, and for years you’ve been hearing that if it did a mega-tsunami would sweep across the Atlantic and hit the US with a 100 foot high wall of water.

Waves from a catastrophic explosion and collapse of the Cumbre Vieja volcano

BBC did a drama about this a bit over ten years ago, and I worked with them on an accompanying science based program aired afterwards debunking their own drama. The model and study that shows the megastunami causing 100ft plus waves on the US east coast assumes every single parameter is the worst possible. One glaring example – it assumes the entire flank of the volcano would slide off into the ocean as a solid, intact slab at just the perfect speed to cause the maximum wave. But of course an explosion big enough to do that would fragment it into a billion pieces. That’s not to say that it can’t cause significant tsunami under the right circumstances, but almost certainly not a megastunami. There are lots of scientific papers and studies out there that show it just can’t happen the way the scare mongers are saying. But, of course, that doesn’t stop the media from hyping it and scaring people who don’t have time to read the journals and see that for every paper saying it’s a big risk (mostly from the same two guys) there are ten saying “how about no.”

Here’s some news reports on the current eruption, along with a brief summary of both the original megatsunami crap and some rebuttals.

#Mexico Earthquake, #AL91, #Larry

There has been a large earthquake on the Pacific coast of Mexico, a magnitude 7 just inland of Acapulco. The initial model estimates are for damages approaching $4 Billion USD, but damage reports from the region are not extensive so far, with only one death reported.

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In the Atlantic, Hurricane Larry continues to be a major hurricane, but is expected to remain well east of Bermuda. Despite that, given the large size, Bermuda should expect tropical storm conditions: Key Messages regarding Hurricane Larry. After passing Bermuda it is expected that Larry will begin to transition to an extratropical system as it passes near or over Vinland (Newfoundland), with blustery conditions and rain for the Canadian Marintines. Larry is also causing impacts along the US coast in the form of swells and rip currents, so if near the beach be careful.

The hurricane center is also watching a disorganized low in the Gulf of Mexico. It is encountering the remains of a front that has stalled over the southeast, and is expected to move over the big bend of Florida then exit off the coast of Georgia by Thursday evening. Aside from some heavy rain and thunderstorms, if you weren’t told it was a tropical system you probably wouldn’t think it unusual for a summer storm. NHC gives it a 50% chance of organizing enough to start advisories. Even if they do, nothing much to worry about – even though close to the coast NHC doesn’t bother with “interests should monitor.”

There are now some storms in the Pacific as well – a weak tropical storm is over the Philippines, and a small but powerful typhoon is headed for the South China Sea between the Philippines and Taiwan:

Impacts are estimated at 1.1 Billion, mostly due to the landfall in China, but a wobble either way bringing the small storm over either Taiwan on the PI could greatly increase that estimate, as well as the number of people at risk …

The smell of death (#Haiti), #Grace and #Mexico, #Henri and #Canada

Grace has passed over Yucatan, causing some impacts in the resort areas but damage appears superficial so far. It should be a hurricane again as it makes landfall on the Mexican coast, and looks to pass north of Mexico City as a decaying tropical storm. Key Messages regarding Tropical Storm Grace (en Español: Mensajes Claves). Here is the forecast impact swath:

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In the Atlantic, Henri has started its turn towards the north, but now appears more likely to hit Canada after passing over its southern neighbor …

Key Messages regarding Tropical Storm Henri from the NHC are at this link. Hurricane and tropical storm watches are in place for the US Coast from (and including) New York City to Cape Cod. The main risk is from urban and small stream flooding, and while Henri should be more of an inconvenience than a danger, given the “target rich” environment even a decaying storm can easily run up $1 billion in impacts in light damage, power outages, and economic disruptions.

As for Haiti, the situation continues to be dire. Anyone who has been in a disaster area, particularly earthquakes and war zones, is forever haunted by the smell that starts a day or so afterwards. The official toll is around 2000, but I suspect the true number is closer to 5000, with recovery of the dead and few remaining survivors progressing slowly due to the timing of the earthquake and the delays caused by the passage of Tropical Storm Grace. One of the hospitals was shut down for two days due to the kidnapping of two doctors by the gangs that run the country – including one of the few orthopedic surgeons. The lack of equipment in most of the area means efforts so far have been by hand, and while some rescues are still taking place, they are with dwindling success. It is a truly horrific situation – here is a CBS report. Between Afghanistan, COVID, and general fatigue over the seemingly intractable ongoing political and economic problems in Haiti, I fear this humanitarian catastrophe is being lost in the noise.