Jascha Polet @CPPGeophysics Twitter profile

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Jascha Polet

@CPPGeophysics

5 years

This is why climbing a tree to escape a bear is not a good approach...

Dick King-Smith HQ

@DickKingSmith

5 years

Black bear female, possibly weighing up to 70kg, is FAST.

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Jascha Polet

@CPPGeophysics

3 years

Today's M7.0 Guerrero earthquake (purple star) in the context of the three large events of 2017/2018 in the same region and the Guerrero gap. Original map from

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Jascha Polet

@CPPGeophysics

2 years

Updated seismicity map of today's earthquakes in Turkey. Events after the original mainshock (M7.8) are in dark purple, lighter purple for the events since the second larger earthquake (M7.6), which appears to have occurred on a different fault system.

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Jascha Polet

@CPPGeophysics

2 years

Geoscientists at Caltech have used micro-seismicity to chart out the structure of sills at depths of 36-43 km that channel magma laterally and upward to recharge the magma chambers of Kilauea and Mauna Loa, demonstrating that they link the volcanoes:

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Jascha Polet

@CPPGeophysics

4 years

M7.6 earthquake near the Kuril Islands appears to be a deep (~50 km) compressional bending event in the outer rise, where the subducting slab bends before it dives into the mantle, which reduces the likelihood of a significant tsunami

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Jascha Polet

@CPPGeophysics

4 years

USGS focal mechanism for M6.5 Idaho earthquake indicates strike-slip faulting, but has a large non double couple component (50%), so this might be a complex event. Borah Peak sequence to the East was normal faulting.

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Jascha Polet

@CPPGeophysics

4 years

A cool observation, pointed out by Martha Savage on Facebook: first motions measured by a seismic network that is so dense that the map view of those first motions looks like a focal mechanism itself Figure: (Does help that the network forms a circle)

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Jascha Polet

@CPPGeophysics

2 years

Now that some more time has passed after the M7.6 earthquake in Turkey, we can see that the aftershocks after that event (in light purple) delineate a different fault zone (trending EW) from those after the M7.8 earthquake (trending NE-SW) that occurred earlier today.

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Jascha Polet

@CPPGeophysics

6 years

Animation surface ground acceleration measured for M6.7 earthquake near Sapporo, Japan today. The highest PGA measured was over 1 g.

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Jascha Polet

@CPPGeophysics

5 years

Especially relevant given the rooftop swimming pool video from the Manila earthquake

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Jascha Polet

@CPPGeophysics

7 years

Quickly made (disclaimer!) map of lake-bed of Lake Texcoco with crowd-sourced damaged and destroyed buildings map for Mexico City

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Jascha Polet

@CPPGeophysics

3 years

I know we have now seen many videos of the eruption in Iceland, but this one is amazing and includes sound. Take my word for it, you want to watch (and hear) this video!

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Jascha Polet

@CPPGeophysics

4 years

This abstract is very to the point (& scary): "Geological, historical, & geophysical observations show that the entire Himalayan arc is poised to produce a sequence of great earthquakes ... The human catastrophe ... is likely to be unprecedented"

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Jascha Polet

@CPPGeophysics

4 years

Local DART buoy shows significant peak to peak open ocean wave height of 3.5 meters for M7.8 Alaska subduction earthquake (only one preliminary measurement at this point in time)

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Jascha Polet

@CPPGeophysics

5 years

Stromboli looking absolutely beautiful this morning! One of my absolute favorite places in the world. Volcanic islands are the best!

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Jascha Polet

@CPPGeophysics

1 year

M6.6 (preliminary) shallow Baja California earthquake, potentially either normal or strike slip event related to local ridge system

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Jascha Polet

@CPPGeophysics

3 years

Fascinating article about the atmosphere-tsunami coupling effects observed for the tsunami generated by the Tonga eruption. Even a rather crappy translation from Japanese to English still results in understandable & important insights into this mechanism:

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Jascha Polet

@CPPGeophysics

5 years

Historical seismicity map of the region of today's M7.7 quake near Jamaica shows that there have been other M7+ earthquakes on this strike-slip system, but today's event is one of the largest in the past hundred or so years.

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Jascha Polet

@CPPGeophysics

3 years

Please note that the relative large signal on the local DART buoy near the hypocenter of the Alaska M8.2 earthquake may be due to the Rayleigh wave, and not a tsunami signal

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Jascha Polet

@CPPGeophysics

2 years

Final update for today. Dark purple circles are the quakes that occurred between the initial M7.8 & subsequent M7.6 earthquake in Turkey, lighter purple the ones after the M7.6. The M7.8 probably occurred on the main strand of the East Anatolian fault, M7.6 on the Sürgü strand.

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Jascha Polet

@CPPGeophysics

8 months

The data for the tsunami due to the M7.5 earthquake in Japan illustrates that waves may be arriving at the coast for several hours and the first wave does not have to be the highest

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Jascha Polet

@CPPGeophysics

2 years

Quick update of the seismicity map of the Turkey earthquake sequence with today's M6.3 at the southern end. (Dark purple: events that occurred between the M7.8 and M7.6; light purple: events that occurred after the M7.6)

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Jascha Polet

@CPPGeophysics

3 years

Now that the Fagradalsfjall eruption in Iceland has started, the live webcam will be a lot more interesting to watch!

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Jascha Polet

@CPPGeophysics

3 years

The sea level monitoring station at Acapulco shows a peak to peak tsunami signal of almost 1 meter, as a result of the M7.0 Guerrero earthquake

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Jascha Polet

@CPPGeophysics

2 years

Early notifications indicate shallow M7.5 earthquake in Michoacan Mexico, mechanism consistent with shallow subduction megathrust event

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Jascha Polet

@CPPGeophysics

3 years

Map of historical seismicity in the general region of today's M7.0 near Guerrero, Mexico, shows an active subduction zone with many large subduction thrust earthquakes in the last century

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Jascha Polet

@CPPGeophysics

8 months

The aftershock pattern (in purple) suggests that the M7.5 Noto earthquake ruptured bilaterally, with the preliminary NEIC slip model also indicating slip on both sides of the epicenter

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Jascha Polet

@CPPGeophysics

4 years

M7.1 earthquake near Honshu, Japan, is located at intermediate depth of 60 km, and thus unlikely to excite a significant tsunami.

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Jascha Polet

@CPPGeophysics

2 years

Analysis of seismic data from event at Nord Stream gas lines appears to indicate explosions according to scientists quoted in

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Jascha Polet

@CPPGeophysics

4 years

A definite drawback of field seismology. Also: the black widows in the off-campus seismometer vault.

Konza Director

@KonzaDirector

4 years

You never know you'll find when you open a data logger box on the prairie...

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Jascha Polet

@CPPGeophysics

3 years

After the 2010 Haiti earthquake, the Coulomb stress changes resulting from that earthquake, as modelled by Eric Calais, showed that the stress increased in the region surrounding the Enriquillo fault both to the east and the west.

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Jascha Polet

@CPPGeophysics

3 years

Today's M7.2 earthquake in Haiti was located less than 100 km to the West of the devastating M7.0 event in 2010.

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Jascha Polet

@CPPGeophysics

3 years

The lava lake is back! Watch the sun rise over Kilauea’s new eruption with these static webcams.

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Jascha Polet

@CPPGeophysics

3 years

The live view of the Iceland eruption now also includes seismograms and a zoom-in on the cone:

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Jascha Polet

@CPPGeophysics

5 years

Very pretty soft sediment deformation due to shaking/earthquake/eruption close to Mono Lake

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Jascha Polet

@CPPGeophysics

2 years

Updated map of Turkey earthquake sequence, with historical seismicity. The events after the M7.6 (light purple) now more clearly delineate the entire rupture & merge to the East with the events after the M7.8 (dark purple). Quakes have continued on the M7.8 EAF segment as well.

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Jascha Polet

@CPPGeophysics

3 years

Geologist mysteriously abducted by aliens?

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Jascha Polet

@CPPGeophysics

6 years

Like clockwork...

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Jascha Polet

@CPPGeophysics

4 years

This is the standard map to show when there is an earthquake in the eastern US, but it does nicely illustrate the fact that quakes of the same magnitude are felt more widely in the East, due to rocks in the West being younger and broken up by faults

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Jascha Polet

@CPPGeophysics

6 years

After all the rain (unfortunately I missed out on the snow), a nice day to capture downtown LA with the snow capped mountains.

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Jascha Polet

@CPPGeophysics

3 years

USGS now has added a M8.1 earthquake after yesterday's original M7.5 South Sandwich event: "this earthquake is part of a complex seismic sequence. Our current interpretation is that this earthquake is the mainshock to a M7.5 that occurred ~170s earlier"

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Jascha Polet

@CPPGeophysics

3 years

Amazing! Energy from the atmospheric wave from the Tonga eruption reflects back from the Andes mountains!

diego aliaga

@diegoaliaga2

3 years

It is incredible to see how the #Andes bounced back part of the #Tonga atmospheric Lamb wave on its first cross over South America!. Here depicted with signal processed IR data from the GOES 16 geostationary satellite

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Jascha Polet

@CPPGeophysics

3 years

A geophysicist’s dream, or how to eliminate three items on a bucket list in one photo

Erika 

@ExploreCosmos_

3 years

BIG THREE!! #Iceland 's Geldingadalur volcano is turning into a must-stop destination for aurora photographers. The latest photo combining geothermal & geomagnetic activity comes from Wioleta Gorecka standing on the banks of the iconic Blue Lagoon. @ThePhotoHour @StormHour

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Jascha Polet

@CPPGeophysics

2 years

Map of seismicity around today's M7.6 Michoacan earthquake, a very active megathrust

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Jascha Polet

@CPPGeophysics

5 years

Photos of the scarp of the M7.1 Ridgecrest earthquake! (The desert is a beautiful place to measure surface offsets.)

Bryan Castillo

@Earthquake_Dude

5 years

Fault Scarp! #RidgecrestEarthquake

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Jascha Polet

@CPPGeophysics

3 years

Just look at those little ants attracted by the heat of the lava...

Brian Emfinger

@brianemfinger

3 years

Wow! Iceland knows how to volcano. From tonight! #icelanderuption #icelandvolcano #iceland

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Jascha Polet

@CPPGeophysics

7 years

Updated solution for North Korea event by Doug Dreger from UCB indicates significant tectonic release in addition to explosive moment

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Jascha Polet

@CPPGeophysics

4 years

Historical earthquake map of the area of today's M6.5 in Idaho from White et al. (2009) with "new" event in purple. West of the Borah Peak sequence.

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Jascha Polet

@CPPGeophysics

5 years

USGS posted a photo on Facebook of a seismometer melted in a fire caused by encroaching lava during the eruption of 2018. “One of the closest monitoring stations to Fissure 8, it sent its last pieces of valuable data as it was being consumed by flames on July 31st, 2018.”

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Jascha Polet

@CPPGeophysics

1 year

M5.6 earthquake in Alberta, Canada, in November, which was the largest earthquake in its recorded history, was “caused by wastewater disposal produced by nearby fracking” and

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Jascha Polet

@CPPGeophysics

2 years

A significant sequence of earthquakes occurred this week in the Tonga-Fiji subduction zone. First several events at great depths (600+ km) within the subducted slab, then today a very different type of event: a deep compressional outer rise earthquake.

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Jascha Polet

@CPPGeophysics

4 years

The M7.8 earthquake in Alaska is now confirmed to be a shallow reverse faulting event, likely on the subduction interface. The epicenter plots very close to or in the Shumagin gap (I added the red dot to a map from )

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Jascha Polet

@CPPGeophysics

1 year

M6.7 earthquake near coast of Ecuador: based on prelim depth, mechanism & location could be intraplate event within subducting slab. This would mean tsunamigenic potential may be relatively low, but significant damage may still be generated by shaking.

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Jascha Polet

@CPPGeophysics

8 months

Significant tsunami waves appear to be incoming (peak to peak waveheight of 1.5 m) at Toyama sea level station due to M7.5 earthquake near west coast of Japan

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Jascha Polet

@CPPGeophysics

2 years

Based on preliminary depth of 60 km and mechanism, M7.3 earthquake near Japan possibly occurred within the subducting slab

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Jascha Polet

@CPPGeophysics

1 year

The M6.9 earthquake in Morocco occurred in a region with mapped faults, but with relatively low historical seismicity. Current reports indicate at least 600 people have been killed in this event and the city of Marrakesh has been badly damaged.

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Jascha Polet

@CPPGeophysics

5 years

USGS animation of relocation of Ridgecrest earthquake sequence, including foreshock sequence & first ~20 hours after M7.1 mainshock. Lots of gaps, which may correspond to areas of large slip in two main events.

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Jascha Polet

@CPPGeophysics

5 years

This video from Stromboli today is a good reminder that pyroclastic flows can travel across water

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Jascha Polet

@CPPGeophysics

3 years

These tide gauge records from Samoa and Kauai from the Tonga eruption illustrate two important points: the first wave may not be the highest and significant waves may continue for hours (Both records show a peak to peak amplitude of around 1 m.)

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Jascha Polet

@CPPGeophysics

6 years

M6.6 reverse faulting earthquake in Japan, which appears to be a lower crustal event based on ~40km depth, and not on the subduction zone interface, followed by a M5.3 aftershock

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Jascha Polet

@CPPGeophysics

8 years

The sights and sounds of a Salton Sea mudvolcano

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Jascha Polet

@CPPGeophysics

5 years

86-floor building in Kuwait was shaken by M7.3 quake at Iran-Iraq border. GPS sites show ground shook with amplitudes of ~40 mm, while building shook up to 160 mm. Motion lasted ~15 minutes after event. 2 amplitude peaks show fundamental modes of building:

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Jascha Polet

@CPPGeophysics

6 years

Unusual chemistry: "flow from Fissure 17 is andesite, unusual for Kilauea, suggesting magma has been sitting in rift for long time. Different than earlier samples, attributed to 1955 magma. Possible magma feeding 17 has been in rift since 1924. (USGS Volcanoes Facebook comment)

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Jascha Polet

@CPPGeophysics

5 years

File under "what not to do during an earthquake"

𝕏𝓐𝓷𝓰𝓮𝓵 𝓔𝓵𝓮𝓶𝓲𝓪𝓱𝕏

@MaximoSPQR

5 years

#caymanislands store during 7.7 #earthquake #Terremoto #Temblor #Sismo #Temblorpr #tsunami 🌊🚨

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Jascha Polet

@CPPGeophysics

2 years

The Palos Verdes fault zone previously was thought to be a segmented network of smaller faults, but a new study suggests it’s a system of interconnected, closely spaced planar fractures from the Santa Monica Bay to Dana Point, capable of a M7.8 earthquake:

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Jascha Polet

@CPPGeophysics

8 months

Today’s M7.5 earthquake in Japan was located at or near the site of a recent intense seismic swarm and transient deformation at Noto Peninsula, which is a non-volcanic/geothermal area far from major plate boundaries.

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Jascha Polet

@CPPGeophysics

11 months

And now a fourth shallow M6.3 earthquake in western Afghanistan with a similar mechanism, a bit to the East of the previous three. I cannot remember ever seeing a sequence like this one.

Jascha Polet

@CPPGeophysics

11 months

After two M6.3 earthquakes a few days ago in the same region killed over 2000 people, a third M6.3 #earthquake hit western #Afghanistan today. Initial locations place this event even closer to the city of Herat.

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Jascha Polet

@CPPGeophysics

7 years

M7.6 Honduras quake is a left lateral strike-slip quake on the Swan Islands Transform Fault

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Jascha Polet

@CPPGeophysics

6 years

The before and after photos showing the landslides after the Hokkaido M6.7 earthquake are amazing

よんます

@yonmas

6 years

今、NHKでも中継見てるけど、信じられない光景……。

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Jascha Polet

@CPPGeophysics

9 months

Significant earthquake offshore in Philippines, early magnitude estimates ~M7.5, depths range from intermediate to shallow. Based on early locations, could be a subduction thrust event.

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Jascha Polet

@CPPGeophysics

5 years

Previous month of Ridgecrest earthquake activity compared to the first few weeks. Clearly activity is decreasing rapidly with time, as expected. Most (larger) quakes in the last month occurred at Northern and Southern end of sequence, maybe a bit closer to the Garlock fault.

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Jascha Polet

@CPPGeophysics

6 years

For those of you teaching Mohr Circles, I recommend Rick Allmendinger's MohrPlotter software, a great tool for lab exercises! (I now remember why I enjoyed structural geology so much as an undergrad..)

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Jascha Polet

@CPPGeophysics

4 years

Active source wave propagation! (Sound on!)

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Jascha Polet

@CPPGeophysics

4 years

A nice map of the tectonics of the area around today's M6.5 Idaho earthquake from a Berkeley Seismo blog post about an earlier sequence a few years ago

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Jascha Polet

@CPPGeophysics

6 years

Bathymetry of Anak Krakatau shows how this center of current eruptive activity is located on the rim of the old crater, near the steep wall of the 1883 caldera, in what is probably an unstable site (Deplus et al., 1995)

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Jascha Polet

@CPPGeophysics

3 years

Amazing rainbow rocks! (And this is not even inside a national park)

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Jascha Polet

@CPPGeophysics

3 years

M7.5 intermediate depth earthquake in Peru shows extension within the subducting slab, which is flat in this region (Flat slab subduction image from )

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Jascha Polet

@CPPGeophysics

4 years

Long period motions due to Mexico earthquake, likely at some distance. Reminds me of a video that was recorded in a park in Tokyo after the Tohoku earthquake.

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Jascha Polet

@CPPGeophysics

1 year

No aftershock of the M6.9 Morocco earthquake has (as of yet) exceeded a magnitude 5. Most aftershocks (purple stars) are located in a cluster towards the NE from the mainshock epicenter.

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Jascha Polet

@CPPGeophysics

8 months

Historical seismicity map of region of today’s M7.5 earthquake in Japan (today’s events in purple). Noto peninsula shows NE-SW alignment of previous reverse faulting seismicity, along trend of mapped faults.

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Jascha Polet

@CPPGeophysics

5 years

This Salton Sea mud volcano had just produced a fresh mud flow from an eruption, similar to a lava flow

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Jascha Polet

@CPPGeophysics

1 year

Map of M7.4 Alaska shallow thrust earthquake today (approximate location with green star) in tectonic context using a figure from the 2021 Chignik earthquake paper from Ye et al. (2022). Today’s event appears to be located in Shumagin gap area.

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Jascha Polet

@CPPGeophysics

4 years

This earthquake really shook me up... possibly due to its depth, it felt very intense, and I actually had time to drop, cover and hold on, while watching the large windows in my living room flex...

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Jascha Polet

@CPPGeophysics

3 years

Updated cross-section of the projected Kermadec seismicity with today's events with thicker outlines, the M8.1 most recent quake is located updip from the earlier M7.4 event, both indicate slip on the subduction zone interface

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Jascha Polet

@CPPGeophysics

6 years

Must admit that I am a bit late with my admiration of this truly awesome NASA Juno Flyby movie of Jupiter, but in my defense, I only had seen it on my iPhone while at AGU, & it is so much better on a bigger screen! More images at

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Jascha Polet

@CPPGeophysics

3 years

The USGS slip map for the M8.2 earthquake indicates that the slip did not reach the trench and therefore this event did not produce a large tsunami.

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Jascha Polet

@CPPGeophysics

4 years

M5.1 earthquake in Carolina is a shallow reverse faulting earthquake with strike slip component in a region of very low historical seismicity

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Jascha Polet

@CPPGeophysics

5 years

Field trip goal! Who’s joining me?

Miguel García Álvarez

@Milhaud

5 years

Cañón Stuðlagil, Islandia. Un monumento a la geología. Fuente:

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Jascha Polet

@CPPGeophysics

1 year

Interesting observation of potential slow slip precursors before larger earthquakes in new Science paper but Dr. Lucy Jones is making some excellent points in this article

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Jascha Polet

@CPPGeophysics

2 years

Also, this map from Duman and Emre (2013) shows some useful background on the local tectonics and fault systems involved, as well as when the last large ruptures occurred in the area of today's Turkey earthquakes.

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Jascha Polet

@CPPGeophysics

3 years

A national park ranger once explained to me what a seismometer was while pointing to the one at our feet, which I had just installed before he got there

Your OG 🐩

@LRNROSE

3 years

whats the funniest thing a man has ever mansplained to you?

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Jascha Polet

@CPPGeophysics

4 years

Shallow M7.8 earthquake in Alaska, no mechanism yet, but hypocentral location would fit with interface thrust event, which would mean that there may be potential for a significant tsunami

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Jascha Polet

@CPPGeophysics

4 years

Map of historical seismicity for today's M7.1 earthquake near Honshu & cross-section with projected mechanisms. M9.1 Tohoku quake is directly up-dip. Based on orientation of mechanism compared to seismicity, this quake may have occurred within subducting slab, not on interface.

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Jascha Polet

@CPPGeophysics

6 years

This screenshot from a USGS drone video over the Kilauea flows is just very.. surreal.. and beautiful(?) and scary

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Jascha Polet

@CPPGeophysics

1 year

Based on the current pattern of aftershocks (from IPMA), it appears the M6.9 Morocco earthquake may have ruptured towards the NE. This directivity could have increased the ground motion (and damage) in Marrakesh.

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@CPPGeophysics

1 year

I generate a quick map and cross-section of the historical seismicity in the region of the M6.8 intraplate earthquake in Ecuador, showing the flat slab subduction in this area.

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Jascha Polet

@CPPGeophysics

5 years

Students had to find the length of the San Andreas fault to use in a lab exercise and Google says... 1 hour and 54 minutes!

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Jascha Polet

@CPPGeophysics

3 years

A tale of two tsunami: looks like tsunami waves from the M8.1 quake are now arriving at a tide gauge station on North Island; the earlier signal is due to the M7.3 earthquake that was located much closer to the area. Both show amplitudes on the order of tens of centimeters.

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Jascha Polet

@CPPGeophysics

5 years

Today's M8.0 earthquake in Northern Peru, a normal faulting event within the subducting plate at ~130 km depth is similar to an M7.5 quake in Ecuador a few months ago at a similar depth and tectonic setting

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Jascha Polet

@CPPGeophysics

4 years

Looks like resonance, similar to the legendary B&W Tacoma bridge video (via @cbdawson )

Global Times

@globaltimesnews

4 years

Authorities have suspended the Humen Bridge in South China's #Guangdong Province. The bridge is reported to be experiencing unusual vibrations: reports.

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