Source: Volcano Discovery

Stromboli (Eolian Islands, Italy): Following a phase of very low activity during most of March-April (often with several hours between small explosions only), activity has picked up again and strombolian-type explosions, mainly from the western and eastern vents in the crater terrace, have been more regular.
According to INGV’s monitoring data, activity of the volcano, internal (seismic) and external (explosions) is at low to moderate levels.

Bardarbunga (Central Iceland): Ever since the large Holuhraun fissure eruption (Aug 2014-Mar 2015), the volcano has remained restless. Over the past months, the volcano’s seismic activity has been showing a slow increase.
The quakes have been concentrated at shallow depths under its central caldera, and the northeastern fissure system (in particular, near Herdubreid volcano). So far, the frequent earthquake swarms have been small and rarely contained quakes above magnitude 3; an eruption in a very near future seems unlikely for now.
However, they indicate that the volcano’s storage system is probably recharging with new shallow magma intrusions; a new eruption of Bardarbunga in a not too distant future (months to years) would certainly not be a big surprise.

Sakurajima (Kyushu, Japan): The activity at the volcano has been irregular. Only few, but sometime relatively strong vulcanian explosions have occurred recently, with ash plumes rising up to 17,000 ft (5 km) altitude.
The Showa crater shows phases of weak continuous degassing (possibly with some ash), suggesting that deep-seated activity might be going on.

During our next visit on location in July we hopefully will find out more details.

Langila (New Britain, Papua New Guinea): A mildly explosive eruption continues at the remote volcano on the western tip of New Britain Island. An ash plume and a thermal hot spot can be seen on satellite imagery.

Sinabung (Sumatra, Indonesia): The explosive / effusive eruption continues with little changes. Rising viscous lava accumulates in the summit crater where as a dome; intermittently, it produces small to moderate explosions (ash plumes rising 1-2 km) and incandescent rockfalls and/or small pyroclastic flows on the eastern side where the crater is breached.
Overall, the activity (which had started in late 2013) seems to be very slowly decreasing over time.

Soputan (North Sulawesi, Indonesia): On 21 April, VSI lowered the alert level from 3 to 2 (on a scale of 1-4), following a decrease in seismic and visible activity from the volcano.

Dukono (Halmahera): Darwin VAAC reported an ash plume at 7,000 ft (2.1 km) altitude drifting SW from the volcano this morning.

Awu (North Sulawesi & Sangihe Islands): VSI raised the alert level of the volcano from 2 (“waspada”) to 3 (“siaga” = eruption warning) yesterday – presumably because of increased seismic activity observed.

Ambrym (Vanuatu): Several lava lakes are currently active in Ambrym (one in Marum, two in Benbow and sometimes one in Mbwelesu craters).
A recent satellite image available through GoogleEarth shows the steam plumes generated by this extraordinary activity.

Ruapehu (North Island): The alert level of the volcano was raised by a notch from 1 to Level 2 (moderate to heightened unrest) last Wednesday, Geonet informed in a special note.
This was triggered by recent measurements that showed an increase in the degassing from Mt Ruapehu’s Crater Lake, a rise in temperature from 25 to 45 deg C since mid April, and ongoing moderate levels of volcanic tremor (reflecting the degassing).
 
The Aviation Color Code was also raised from Green to Yellow.

Turrialba (Costa Rica): A relatively strong explosion (the strongest so far in the ongoing series of intermittent eruptions) occurred yesterday morning at the volcano at 01:18 local time. The eruption only lasted a few minutes, but generating a shower of incandescent fragments and an ash plume that rose 3 km and drifted southeast across the Central Valley.
As a result, the regional Tobías Bolaños Airport in western San José was temporarily closed because of the ash plume, and reopened later in the morning.

Currently erupting:

Alaid (Northern Kuriles): intense thermal signal from summit crater, strong degassing (updated 3 May 2016)
Ambrym (Vanuatu): active lava lakes in several craters (updated 13 May 2016)
Aso (central Kyushu, Japan): degassing, sporadic steam / ash explosions (updated 8 Mar 2016)
Batu Tara (Sunda Islands, Indonesia): strombolian explosions, ash plumes up to 500 m, extrusion of a small lava dome with rockfalls (updated 28 Nov 2015)
Bristol Island (United Kingdom, South Sandwich Is): new eruption since late April 2016 (updated 4 May 2016)
Chikurachki (Paramushir Island): new eruption since end of March 2016 (updated 31 Mar 2016)
Colima (Western Mexico): sporadic small explosions (updated 5 May 2016)
Copahue (Chile/Argentina): seismic unrest, occasional ash venting (updated 22 Mar 2016)
Dukono (Halmahera): mild strombolian activity, continuous intense ash emissions (updated 13 May 2016)
Erebus (Antarctica): active lava lake in summit crater (updated 8 Dec 2014)
Erta Ale (Danakil depression, Ethiopia): overflowing lava lake (updated 2 Mar 2016)
Fuego (Guatemala): lava flows on S and W flanks, lava fountaining from summit vent (updated 8 May 2016)
Ibu (Halmahera, Indonesia): stromolian and phreatomagmatic explosions (updated 29 Oct 2015)
Karymsky (Kamchatka): occasional small explosions, thermal anomaly (updated 5 May 2016)
Kerinci (Sumatra): intermittent ash emissions (updated 1 May 2016)
Kilauea (Hawai’i): new lava flow from vents on NE flank of Pu’u ‘O’o (updated 28 Apr 2015)
Kliuchevskoi (Kamchatka): mild strombolian activity in summit crater (updated 27 Apr 2016)
Langila (New Britain, Papua New Guinea): ash emissions (updated 13 May 2016)
Masaya (Nicaragua): active lava lake ini summit crater (updated 6 May 2016)
Momotombo (Nicaragua): intermittent vulcanian explosions (updated 29 Mar 2016)
Nyiragongo (DRCongo): new vent on crater floor (updated 8 Mar 2016)
Ol Doinyo Lengai (Tanzania): effusion of natrocarbonatite lava inside the crater (updated 8 Jul 2013)
Pacaya (Guatemala): intense spattering from intra-crater cone (updated 29 Mar 2016)
Popocatépetl (Central Mexico): degassing, sporadic explosions, slowly growing lava dome (updated 20 Apr 2016)
Rabaul (Tavurvur) (New Britain, Papua New Guinea): lava fountains, ash emissions from Tavurvur cone (updated 12 Sep 2014)
Reventador (Ecuador): lava flow on SW flank (updated 24 Feb 2016)
Sakurajima (Kyushu, Japan): sporadic vulcanian explosions from Minamidake and Showa crater (updated 13 May 2016)
Sangay (Ecuador): mild strombolian activity in summit crater (updated 6 May 2016)
Santiaguito (Guatemala): increased effusive / explosive activity from Caliente dome (updated 8 May 2016)
Semeru (East Java, Indonesia): growing lava dome, lava flow, strombolian activity (updated 14 Feb 2016)
Shiveluch (Kamchatka): growing lava dome (updated 9 May 2016)
Sinabung (Sumatra, Indonesia): continuing pyroclastic flows (updated 13 May 2016)
Stromboli (Eolian Islands, Italy): weak, intermittent strombolian explosions (updated 13 May 2016)
Suwanose-jima (Ryukyu Islands): strombolian explosions in Ontake crater (updated 20 Apr 2016)
Tungurahua (Ecuador): large and frequent explosions, ash columns rising several km (updated 9 Mar 2016)
Turrialba (Costa Rica): steaming, sporadic ash emissions (updated 13 May 2016)
Ubinas (Peru): sporadic vulcanian explosions (updated 16 Jan 2016)
Villarrica (Central Chile): lava lake in summit crater, spattering, strombolian explosions (updated 4 Apr 2016)
Yasur (Tanna Island, Vanuatu): ash emissions, weak strombolian explosions (updated 13 Nov 2015)
Zhupanovsky (Kamchatka, Russia): steaming / degassing (updated 31 Mar 2016)

Eruption warning / minor activity:

Awu (North Sulawesi & Sangihe Islands): seismic unrest, eruption warning (updated 13 May 2016)
Bagana (Bougainville Island, Papua New Guinea): intermittent mild ash emissions (updated 8 May 2016)
Barren Island (Indian Ocean): weak thermal hot spot (updated 3 Mar 2016)
Bezymianny (Central Kamchatka Depression): steaming, weak seismic activity (updated 3 Jul 2014)
Bromo (East Java, Indonesia): intermittent weak ash emissions (updated 6 May 2016)
Bulusan (Luzon Island, Philippines): occasional sporadic explosions (updated 23 Feb 2016)
Canlaon (Central Philippines): occasional sporadic explosions (updated 30 Mar 2016)
Cerro Negro (Nicaragua): increased earthquake activity (updated 16 Feb 2016)
Chirinkotan (Northern Kuriles, Russia): sporadic ash emissions (updated 28 Jul 2015)
Chirpoi (Kurile Islands, Russia): thermal hot spot visible on satellite imagery (updated 14 Apr 2016)
Cleveland (Aleutian Islands, Alaska): sporadic explosions (updated 6 May 2016)
Cotopaxi (Ecuador): vulcanian explosions (updated 16 Aug 2015)
Etna (Sicily, Italy): weak, dilute ash emissions from NE crater (updated 19 Apr 2014)
Heard (Australia, Southern Indian Ocean): strombolian activity, lava flow from Mawson Peak summit crater (updated 1 Feb 2016)
Karangetang (Siau Island, Sangihe Islands, Indonesia): rockfalls, glowing lava dome (updated 13 Jan 2016)
Kavachi (Solomon Islands): no eruption since 2007 (updated 16 Jun 2014)
Kick ’em Jenny (West Indies, Grenada): volcanic unrest, eruption warning (updated 24 Jul 2015)
Krakatau (Sunda Strait, Indonesia): steaming, seismic unrest (updated 15 Nov 2015)
Kuchinoerabu-jima (Ryukyu Islands): large explosive eruption on 29 May 2015 (updated 27 Mar 2015)
Lascar (Northern Chile): sudden explosion on 30 Oct 2015 (updated 31 Oct 2015)
Lokon-Empung (North Sulawesi, Indonesia): seismic unrest, eruption warning (updated 9 Mar 2016)
Lopevi (Vanuatu): eruption warning (updated 16 Dec 2014)
MacDonald (Austral Islands,  ): steaming observed (updated 6 Feb 2016)
Manam (Papua New Guinea): large explosion on 31 July 2015 (updated 4 Mar 2016)
Mayon (Luzon Island, Philippines): steaming (updated 18 Dec 2014)
Merapi (Central Java, Indonesia): sporadic phreatic explosions (updated 21 Aug 2015)
Michael (United Kingdom, South Sandwich Is): unspecified activity detected as hot spot on satellite data (updated 3 Oct 2015)
Nevado del Ruiz (Colombia): intermittent explosions, steaming, ash venting (updated 3 May 2016)
Nevados de Chillán (Central Chile): sporadic ash emissions, seismic unrest (updated 9 May 2016)
Niigata-Yake-yama (Honshu): sporadic explosions, seismic unrest (updated 8 May 2016)
Nyamuragira (DRCongo): lava lake in summit crater disappeared in early April 2016 (updated 16 Apr 2016)
Ontake-san (Honshu): steaming, low seismic activity (updated 18 Dec 2014)
Papandayan (West Java): steaming (updated 6 May 2013)
Poas (Costa Rica): phreatic explosions (updated 14 Oct 2014)
Rasshua (Central Kuriles)
Raung (East Java): intra-caldera eruption with lava flow and strombolian activity (updated 27 Aug 2015)
Rincón de la Vieja (Costa Rica): sproadic hydrothermal explosions (updated 3 May 2016)
Sabancaya (Peru): steaming, elevated seismic activity (updated 11 Oct 2015)
Sacabaya (Northern Chile, Bolivia and Argentina)
San Cristobal (Nicaragua): intermittent ash explosions (updated 24 Apr 2016)
San Miguel (El Salvador): intermittent ash emissions (updated 15 Jan 2016)
Sangeang Api (Indonesia): weak lava extrusion from summit crater (updated 11 Nov 2015)
Sirung (Pantar Island, Indonesia ): degassing (updated 10 Jul 2015)
Slamet (Central Java): steam emissions (updated 12 Jan 2015)
Telica (Nicaragua): lava glow from crater, degassing, occasional light ash emissions (updated 9 May 2016)
Ulawun (New Britain, Papua New Guinea): degassing, ash venting (updated 5 Aug 2013)

More continued coverage and updates at Volcano Discovery: Volcanic Activity Worldwide 6 May 2016