This style adds a few POIS related to Tsunami plus Surface / Roads with damages, obstacles. The surfaces and roads are colored in red. Block nodes are represented with an X. And finally, areas tagged with natural=wetland and wetland=tsunami are represented with the Marsh symbol.

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meta 
{
    title: "Japan Tsunami POIS";
    description: "POIS related to Tsunami plus Surface / Roads with damages, obstacles";
    icon: "icons/hot.16.png";
    version: "1.24_2020-10-31";
    author: "PierZen";
    link: "http://josm.openstreetmap.de/wiki/Styles/JP-Tsunami"; 
}
/*
   Icons source : Lübeck POI Map, Potlatch2 and JOSM.
*/
/* control node size to help vizualise damaged zones at lower zoom levels */
node[note] { icon-size:4; z-index: 1;}
node|z1-17 { symbol-shape: square; symbol-stroke-color: rosybrown; symbol-fill-color: rosybrown; symbol-size: 1; z-index:1}
node|z18 { symbol-shape: square; symbol-stroke-color: navy; symbol-fill-color: rosybrown; symbol-size:5;  z-index:1}
node|z19- { symbol-shape: square; symbol-stroke-color: navy; symbol-fill-color: rosybrown; symbol-size:6;  z-index:1}
node|z1-14[power] { icon-size:8; z-index:21;}
node|z15-[power] { icon-size:16; z-index:21;}
/* icons */
node[amenity=kindergarten] { icon-image: "icons/education_nursery3.n.16.png"; z-index: 20; }
node[amenity=nursing_home] { icon-image: "icons/hot_nurse.16.png"; z-index: 20; }
node[amenity=community_centre],
node[amenity=comunity_centre],
node[amenity=social_facility] { icon-image: "icons/hot_social_facility.16.png"; z-index: 20; }
node[amenity=public_building] { icon-image: "icons/hot_public_building.16.png"; z-index: 20; }
node[leisure=playground] { icon-image: "icons/amenity_playground.n.16.png"; z-index: 20; }
node[amenity=post_office] { icon-image: "icons/amenity_post_box.n.16.png"; z-index: 20; }
node[social_facility=food_bank] { icon-image: "icons/hot_social_food_bank.16.png"; z-index: 20; }
node[amenity=crematorium] { icon-image: "icons/hot_crematorium.16.png"; z-index: 20; }
node[amenity=mortuary] { icon-image: "icons/hot_mortuary.16.png"; z-index: 20; }
node[aeroway=helipad] { icon-image: "icons/hot_helipad.16.png"; z-index: 20; }
node[power=generator] { icon-image: "icons/nuclear.png"; z-index: 20; }
node[power=generator][power_source=nuclear] { icon-image: "icons/hot_nuclear_power.16.png"; z-index: 10; }
node[power=generator]["generator:source"=nuclear] { icon-image: "icons/hot_nuclear_power.16.png"; z-index: 10; }
node[impassable="YES"], node[impassable=yes], node[obstacletype], node[barrier:obstacletype],
node[barrier:obstacle], node[barrier:obstacle_type], node[Barrier:obstacle_type],
node[barrier:damage_type], node[barrier^=debris], node[barrier^="flooded"], node[earthquake:damage], node[tsunami:damage],
node[blocked=yes], node[barrier=obstacle], node[highway][barrier:obstacle_type=debris]
  { icon-image: "icons/hot_obstacle.16.png"; z-index: 22;}
/* priority nodes - showed from zoom level 8 */
node|z8-13[amenity=kindergarten], node|z8-13[amenity=nursing_home],
node|z8-13[amenity=community_centre], node|z8-13[amenity=comunity_centre],
node|z8-13[amenity=social_facility], node|z8-13[amenity=public_building],
node|z8-13[leisure=playground], node|z8-13[amenity=post_office],
node|z8-13[social_facility=food_bank], node|z8-13[amenity=crematorium],
node|z8-13[amenity=mortuary]  { icon-size:8;}
node|z14-16[amenity=kindergarten], node|z14-16[amenity=nursing_home],
node|z14-16[amenity=community_centre], node|z14-16[amenity=comunity_centre],
node|z14-16[amenity=social_facility], node|z14-16[amenity=public_building],
node|z14-16[leisure=playground], node|z14-16[amenity=post_office],
node|z14-16[social_facility=food_bank], node|z14-16[amenity=crematorium],
node|z14-16[amenity=mortuary]  { icon-size:12;}
node|z17-[amenity=kindergarten], node|z17-[amenity=nursing_home],
node|z17-[amenity=community_centre], node|z17-[amenity=comunity_centre],
node|z17-[amenity=social_facility], node|z17-[amenity=public_building],
node|z17-[leisure=playground], node|z17-[amenity=post_office],
node|z17-[social_facility=food_bank], node|z17-[amenity=crematorium],
node|z17-[amenity=mortuary]  { icon-size:16;}
node|z10-[aeroway=helipad], node|z10-[power=generator], node|z10-[power=generator],
node|z10-[impassable="YES"], node|z10-[impassable=yes],
node|z10-[obstacletype], node[barrier:obstacletype],
node|z10-[barrier:obstacle], node[barrier:obstacle_type], node[Barrier:obstacle_type],
node|z10-[barrier:damage_type], node[barrier=debris],
node|z10-[earthquake:damage], node[tsunami:damage],
node|z10-[blocked=yes], node[barrier=obstacle],
node|z10-[highway][barrier:obstacle_type=debris]  { icon-size:16;}
/* wetland */
area[natural=wetland] { fill-image: "icons/marsh.png"; z-index: 19;}
/* debris, damage areas */
area[building=collapsed] {color:red;  width:10; fill-color: red; opacity:1.0; z-index: 21;}
area[landuse=brownfield],
area[obstacletype=debris], area[tsunami]  {color:red;  width:4; fill-color: red; opacity:0.4; z-index: 20;}
area[natural=wetland][wetland=tsunami] { color: red; width:4; opacity:0.3;  fill-color: red; fill-image: "icons/marsh.png"; z-index: 19;}
/* impassable ways */
way[access=closed], way[practicability=no], way[barrier=obstacle],
way[impassable="YES"], way[impassable=yes] { color: orange;  casing-color: red; dashes: 2, 8; z-index: 19;}
way[railway] { casing-color: navy; width: +2; casing-width: 8; color: navy; dashes: 12, 12; z-index: 19;}
way[railway][earthquake:damage], way[railway][tsunami:damage],
way[railway][access=closed], way[railway][practicability=no], way[railway][barrier=obstacle], way[railway][impassable=YES], way[railway][impassable=yes]  { casing-color: red; casing-width: 8; color: orange; dashes: 12, 12; z-index: 19;}

Styles_JP-Tsunami-style.mapcss, Styles_JP-Tsunami.zip