Ischia earthquake

https://earthquake.usgs.gov/earthquakes/eventpage/us2000aaae#executive
M 4.3 - 5km NW of Monte di Procida, Italy
2017-08-21 18:57:53 UTC 40.830°N 14.000°E 10.4 km depth

https://earthquake.usgs.gov/earthquakes/eventpage/us2000aaae#dyfi
Two responses from Ischia reporting MMI Intensity of IV.
https://en.wikipedia.org/wiki/Mercalli_intensity_scale

IV. Light Felt indoors by many, outdoors by few during the day. At
night, some awakened. Dishes, windows, doors disturbed; walls make
cracking sound. Sensation like heavy truck striking building. Standing
motor cars rocked noticeably.

Factoid: Giuseppe Mercalli was an Italian volcanologist.

Looks worst than a MMI of IV. I'm wondering if the buildings are unreinforced masonry. CNN reports one fatality:
http://www.cnn.com/2017/08/21/world/italy-earthquake-gulf-of-naples/index.html

One person was killed and rescuers were trying to reach seven people
buried under rubble after an earthquake hit the Italian island of
Ischia, a police official told CNN late Monday.

At least 25 injuries were reported on the resort island, according to
public broadcaster RAI.

The victim, an elderly woman, was hit by debris in the town of
Casamicciola, said Col. Giovanni Salerno of the Finance Police Naples
province unit. The island is in the Gulf of Naples. An infant and a
7-year-old boy were among those trapped in the rubble, police said.

I heard about the earthquake in a news bulletin but haven't seen any details yet. Thankfully it appears to be a small earthquake.

More recent reports:
http://www.telegraph.co.uk/news/2017/08/21/earthquake-strikes-historic-italian-island-ischia-causing-buildings/

Television images showed that about six buildings in the town of
Casamicciola as well as a church had collapsed in the quake, which hit
at 8:57 p.m. (1857 GMT).

Roberto Allocca, a doctor from a local hospital, told Sky TG24
television that about 25 people had been treated for minor injuries.
Most of the hospital had been evacuated and the injured were treated
outside.

Police said all but one of the people known to be trapped were
responding to rescuers and were expected to be extracted alive. One
person, however, wasn't responding, raising worries the death toll
could rise, said Giovanni Salerno of the financial police.

Salerno confirmed one person was killed by falling masonry from a
church.

Italy's National Institute of Geophysics and Vulcanology (INGV) put
the magnitude at 4.0 but both the U.S. Geological Survey (USGS) and
the European quake agency, EMSC, estimated the magnitude at 4.3.

http://www.nbcnews.com/news/world/one-dead-20-injured-after-quake-strikes-italian-tourist-island-n794701

Ischia is literally sitting over a volcano, so earthquakes are always possible. They are a kind of earthquakes somewhat different from the usual ones due to earth faults, not completely understood in their dynamics and this explains why there are different evaluations about the magnitudo of the earthquake. Such earthquakes are very superficial - would you dig five kms. under the surface, you would find hot lava that is elastic and does not fracture - so even light earthquakes can cause damages.

We should also add that South Italy has a culture of raising unlicensed buildings - partly due to inefficiencies in public administration, partly due to tax evasion - so building standards are often low.

Please do not confuse the Richter scale of earthquake measurements, based on the energy generated by the earthquake and the old Mercalli scale, based on the observed damages. The Ischia earthquake was around 4.0 on the Richter scale (that is a logarithmic one, so a one point increase is a big increase in the total energy).

I'm also travelling to Ischia in October with family-including a 4 year old and an 84 year old. Apart from the fear of further earthquakes, I'm afraid, after reading that seismic activity can increase the likelihood of a volcanic eruption in the area. I don't know whether to go, now, or not.

Please do not confuse the Richter scale of earthquake measurements, based on the energy generated by the earthquake and the old Mercalli scale, based on the observed damages.

The American USGS reports Moment Magnitude (computed from seismograph readings) and Modified Mercalli Intensity (by subjective reporting). The USGS reports the event's Moment Magnitude to be M.2 and the three reports from Ischia, Campania average to a MMI of "IV". Ischia, Campania is 9 km from the epicenter.

Moment Magnitude is not the same as a Richter Magnitude but for medium intensity earthquakes, the two are close. Both are logarithmic meaning that the difference between a 4 and a 5 is big (a MM = 5 having some 33 time as much energy as a MM = 4).
https://en.wikipedia.org/wiki/Moment_magnitude_scale

The Modified Mercalli Intensity is keyed to what people on the ground feel and see. The Ischia observers (9 km from the epicenter) reported a MMI = IV or "Light" earthquake. The Naples observer (29 km) reported a MMI = I or "Not Felt".
https://en.wikipedia.org/wiki/Mercalli_intensity_scale

AS previously noted, the EQ event was not a big one yet resulted in at least one fatality and a number of building collapses. This lends credibility to the comment about poor building quality.

Good news.
http://www.newser.com/story/247576/good-news-times-3-in-italy-quake-rescue.html?utm_source=part&utm_medium=uol&utm_campaign=rss_top

A preteen being hailed as a hero in the earthquake that rocked
Italy's Ischia island Monday was yanked out of the rubble Tuesday
afternoon, as were his two little brothers, whom he's credited with
saving. The BBC reports that 11-year-old Ciro was the last of the
three siblings to be pulled out of the debris—his 7-month-old brother,
Pasquale, and 8-year-old brother, Mattias, were rescued earlier
Tuesday, and it's said Ciro may have ensured at least one brother's
survival by pushing Mattias under a bed in the family's home when the
quake started.

Duck and cover also applies to EQs. Running out into the street can be worst than sheltering under a table or deck if the masonry collapses into the street.

https://www.ready.gov/earthquakes

If you are inside a building:

Drop down onto your hands and knees so the earthquake doesn’t knock
you down. Drop to the ground (before the earthquake drops you!)

Cover your head and neck with your arms to protect yourself from
falling debris....

Stay where you are until the shaking stops. Do not run outside. Do not
get in a doorway as this does not provide protection from falling or
flying objects, and you may not be able to remain standing.

and more....

If you are outside when you feel the shaking:

If you are outdoors when the shaking starts, move away from buildings,
streetlights, and utility wires. Once in the open, “Drop, Cover, and
Hold On.” Stay there until the shaking stops.

Most people think of Vesuvius when visiting Naples, never realizing one of the largest calderas in the world is located there. 24 volcanos and vents mostly under water are located by Pozzioli, just west of the city. Seismic activity is measured and reported daily.

Interesting article about what someone said earlier regarding the illegal buildings in the south. From the article:

"But it is Campania -- encompassing Naples and Ischia island -- which is dubbed the "Russian Roulette of Italy" by experts because of its deadly mix of illegal houses, a high-density population and the active volcano Vesuvius."

https://www.thelocal.it/20170823/experts-warn-that-illegal-construction-threatens-lives-of-millions

Rik,
Thanks for the link to the report explaining the amount of damage for a relatively small (MM=4.3) EQ.

The following report has a number of photographs of the rescue effort. It looks like it could take months to recover.
http://www.express.co.uk/news/world/844356/Ischia-earthquake-Naples-Italy-tourists-evacuate-ferry-pay-queue